Emacs is the extensible, customizable, self-documenting real-time display editor. This Info file describes how to edit with Emacs and some of how to customize it; it corresponds to GNU Emacs version 22.0.50.
For information on extending Emacs, see Emacs Lisp.
Indexes (nodes containing large menus)
Important General Concepts
Fundamental Editing Commands
Important Text-Changing Commands
Major Structures of Emacs
Advanced Features
Recovery from Problems
Detailed Node Listing ---------------------
Here are some other nodes which are really inferiors of the ones already listed, mentioned here so you can get to them in one step:
The Organization of the Screen
Basic Editing Commands
The Minibuffer
Help
The Mark and the Region
Killing and Moving Text
Yanking
Registers
Controlling the Display
Searching and Replacement
Replacement Commands
Commands for Fixing Typos
Keyboard Macros
File Handling
Saving Files
Version Control
Using Multiple Buffers
Multiple Windows
Frames and X Windows
International Character Set Support
Major Modes
Indentation
Commands for Human Languages
Filling Text
Editing Programs
Top-Level Definitions, or Defuns
Indentation for Programs
Commands for Editing with Parentheses
Manipulating Comments
Documentation Lookup
C and Related Modes
Fortran Mode
Compiling and Testing Programs
Running Debuggers Under Emacs
Maintaining Programs
Tags Tables
Merging Files with Emerge
Abbrevs
Editing Pictures
Sending Mail
Reading Mail with Rmail
Dired, the Directory Editor
The Calendar and the Diary
Movement in the Calendar
Conversion To and From Other Calendars
The Diary
Gnus
Running Shell Commands from Emacs
Using Emacs as a Server
Hyperlinking and Navigation Features
Customization
Variables
Customizing Key Bindings
The Init File, ~/.emacs
Dealing with Emacs Trouble
Reporting Bugs
Command Line Arguments for Emacs Invocation
Environment Variables
X Options and Resources
Emacs and Mac OS
MS-DOS and Windows 95/98/NT
GNU Emacs is free software; this means that everyone is free to use it and free to redistribute it on certain conditions. GNU Emacs is not in the public domain; it is copyrighted and there are restrictions on its distribution, but these restrictions are designed to permit everything that a good cooperating citizen would want to do. What is not allowed is to try to prevent others from further sharing any version of GNU Emacs that they might get from you. The precise conditions are found in the GNU General Public License that comes with Emacs and also appears in this manual1. See Copying.
One way to get a copy of GNU Emacs is from someone else who has it. You need not ask for our permission to do so, or tell any one else; just copy it. If you have access to the Internet, you can get the latest distribution version of GNU Emacs by anonymous FTP; see http://www.gnu.org/software/emacs on our website for more information.
You may also receive GNU Emacs when you buy a computer. Computer manufacturers are free to distribute copies on the same terms that apply to everyone else. These terms require them to give you the full sources, including whatever changes they may have made, and to permit you to redistribute the GNU Emacs received from them under the usual terms of the General Public License. In other words, the program must be free for you when you get it, not just free for the manufacturer.
You can also order copies of GNU Emacs from the Free Software Foundation. This is a convenient and reliable way to get a copy; it is also a good way to help fund our work. We also sell hardcopy versions of this manual and An Introduction to Programming in Emacs Lisp, by Robert J. Chassell. You can find an order form on our web site at http://www.gnu.org/order/order.html. For further information, write to
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You are reading about GNU Emacs, the GNU incarnation of the advanced, self-documenting, customizable, extensible real-time display editor Emacs. (The `G' in `GNU' is not silent.)
We say that Emacs is a display editor because normally the text being edited is visible on the screen and is updated automatically as you type your commands. See Display.
We call it a real-time editor because the display is updated very frequently, usually after each character or pair of characters you type. This minimizes the amount of information you must keep in your head as you edit. See Real-time.
We call Emacs advanced because it provides facilities that go beyond simple insertion and deletion: controlling subprocesses; automatic indentation of programs; viewing two or more files at once; editing formatted text; and dealing in terms of characters, words, lines, sentences, paragraphs, and pages, as well as expressions and comments in several different programming languages.
Self-documenting means that at any time you can type a special character, Control-h, to find out what your options are. You can also use it to find out what any command does, or to find all the commands that pertain to a topic. See Help.
Customizable means that you can change the definitions of Emacs commands in little ways. For example, if you use a programming language in which comments start with ‘<**’ and end with ‘**>’, you can tell the Emacs comment manipulation commands to use those strings (see Comments). Another sort of customization is rearrangement of the command set. For example, if you prefer the four basic cursor motion commands (up, down, left and right) on keys in a diamond pattern on the keyboard, you can rebind the keys that way. See Customization.
Extensible means that you can go beyond simple customization and write entirely new commands, programs in the Lisp language to be run by Emacs's own Lisp interpreter. Emacs is an “on-line extensible” system, which means that it is divided into many functions that call each other, any of which can be redefined in the middle of an editing session. Almost any part of Emacs can be replaced without making a separate copy of all of Emacs. Most of the editing commands of Emacs are written in Lisp; the few exceptions could have been written in Lisp but are written in C for efficiency. Although only a programmer can write an extension, anybody can use it afterward. See Emacs Lisp Intro, if you want to learn Emacs Lisp programming.
When run under the X Window System, Emacs provides its own menus and convenient bindings to mouse buttons. But Emacs can provide many of the benefits of a window system on a text-only terminal. For instance, you can look at or edit several files at once, move text between files, and edit files while running shell commands.
On a text-only terminal, the Emacs display occupies the whole screen. On the X Window System, Emacs creates its own X windows to use. We use the term frame to mean an entire text-only screen or an entire X window used by Emacs. Emacs uses both kinds of frames in the same way to display your editing. Emacs normally starts out with just one frame, but you can create additional frames if you wish. See Frames.
When you start Emacs, the entire frame except for the top and bottom is devoted to the text you are editing. This area is called the window. At the top there is normally a menu bar where you can access a series of menus; then there may be a tool bar, a row of icons that perform editing commands if you click on them. Below this, the window begins. The last line is a special echo area or minibuffer window, where prompts appear and where you enter information when Emacs asks for it. See below for more information about these special lines.
You can subdivide the large text window horizontally or vertically into multiple text windows, each of which can be used for a different file (see Windows). In this manual, the word “window” always refers to the subdivisions of a frame within Emacs.
At any time, one window is the selected window. On graphical terminals, the selected window normally shows a more prominent cursor (solid and blinking) while other windows show a weaker cursor (such as a hollow box). On text terminals, which have just one cursor, that cursor appears in the selected window.
Most Emacs commands implicitly apply to the text in the selected window (though mouse commands generally operate on whatever window you click them in, whether selected or not). The other windows display text for reference only, unless/until you select them. If you use multiple frames under the X Window System, then giving the input focus to a particular frame selects a window in that frame.
Each window's last line is a mode line, which describes what is going on in that window. It appears in different color and/or a “3D” box, if the terminal supports that; its contents normally begin with ‘--:-- *scratch*’ when Emacs starts. The mode line displays status information such as what buffer is being displayed above it in the window, what major and minor modes are in use, and whether the buffer contains unsaved changes.
Within Emacs, the active cursor shows the location at which editing commands will take effect. This location is called point. Many Emacs commands move point through the text, so that you can edit at different places in it. You can also place point by clicking mouse button 1.
While the cursor appears to point at a character, you should think of point as between two characters; it points before the character that appears under the cursor. For example, if your text looks like ‘frob’ with the cursor over the ‘b’, then point is between the ‘o’ and the ‘b’. If you insert the character ‘!’ at that position, the result is ‘fro!b’, with point between the ‘!’ and the ‘b’. Thus, the cursor remains over the ‘b’, as before.
Sometimes people speak of “the cursor” when they mean “point,” or speak of commands that move point as “cursor motion” commands.
If you are editing several files in Emacs, each in its own buffer, each buffer has its own point location. A buffer that is not currently displayed remembers its point location in case you display it again later. When Emacs displays multiple windows, each window has its own point location. If the same buffer appears in more than one window, each window has its own position for point in that buffer, and (when possible) its own cursor.
A text-only terminal has just one cursor, so Emacs puts it in the selected window. The other windows do not show a cursor, even though they do have a location of point. When Emacs updates the screen on a text-only terminal, it has to put the cursor temporarily at the place the output goes. This doesn't mean point is there, though. Once display updating finishes, Emacs puts the cursor where point is.
On graphical terminals, Emacs shows a cursor in each window; the selected window's cursor is solid and blinking, and the other cursors are just hollow. Thus, the most prominent cursor always shows you the selected window, on all kinds of terminals.
See Cursor Display, for customizable variables that control display of the cursor or cursors.
The term “point” comes from the character ‘.’, which was the command in TECO (the language in which the original Emacs was written) for accessing the value now called “point.”
The line at the bottom of the frame (below the mode line) is the echo area. It is used to display small amounts of text for various purposes.
Echoing means displaying the characters that you type. At the command line, the operating system normally echoes all your input. Emacs handles echoing differently.
Single-character commands do not echo in Emacs, and multi-character commands echo only if you pause while typing them. As soon as you pause for more than a second in the middle of a command, Emacs echoes all the characters of the command so far. This is to prompt you for the rest of the command. Once echoing has started, the rest of the command echoes immediately as you type it. This behavior is designed to give confident users fast response, while giving hesitant users maximum feedback. You can change this behavior by setting a variable (see Display Custom).
If a command cannot be executed, it may display an error message in the echo area. Error messages are accompanied by beeping or by flashing the screen. The error also discards any input you have typed ahead.
Some commands display informative messages in the echo area. These messages look much like error messages, but they are not announced with a beep and do not throw away input. Sometimes the message tells you what the command has done, when this is not obvious from looking at the text being edited. Sometimes the sole purpose of a command is to show you a message giving you specific information—for example, C-x = (hold down <CTRL> and type x, then let go of <CTRL> and type =) displays a message describing the character position of point in the text and its current column in the window. Commands that take a long time often display messages ending in ‘...’ while they are working, and add ‘done’ at the end when they are finished.
Echo-area informative messages are saved in an editor buffer named ‘*Messages*’. (We have not explained buffers yet; see Buffers, for more information about them.) If you miss a message that appears briefly on the screen, you can switch to the ‘*Messages*’ buffer to see it again. (Successive progress messages are often collapsed into one in that buffer.)
The size of ‘*Messages*’ is limited to a certain number of lines.
The variable message-log-max specifies how many lines. Once the
buffer has that many lines, each line added at the end deletes one line
from the beginning. See Variables, for how to set variables such as
message-log-max.
The echo area is also used to display the minibuffer, a window that is used for reading arguments to commands, such as the name of a file to be edited. When the minibuffer is in use, the echo area begins with a prompt string that usually ends with a colon; also, the cursor appears in that line because it is the selected window. You can always get out of the minibuffer by typing C-g. See Minibuffer.
Each text window's last line is a mode line, which describes what is going on in that window. When there is only one text window, the mode line appears right above the echo area; it is the next-to-last line in the frame. The mode line starts and ends with dashes. On a text-mode display, the mode line is in inverse video if the terminal supports that; on a graphics display, the mode line has a 3D box appearance to help it stand out. The mode line of the selected window has a slightly different appearance than those of other windows; see Optional Mode Line, for more about this.
Normally, the mode line looks like this:
-cs:ch buf pos line (major minor)------
This gives information about the buffer being displayed in the window: the buffer's name, what major and minor modes are in use, whether the buffer's text has been changed, and how far down the buffer you are currently looking.
ch contains two stars ‘**’ if the text in the buffer has been edited (the buffer is “modified”), or ‘--’ if the buffer has not been edited. For a read-only buffer, it is ‘%*’ if the buffer is modified, and ‘%%’ otherwise.
buf is the name of the window's buffer. In most cases this is the same as the name of a file you are editing. See Buffers.
The buffer displayed in the selected window (the window that the cursor is in) is also Emacs's current buffer, the one that editing takes place in. When we speak of what some command does to “the buffer,” we are talking about the current buffer.
pos tells you whether there is additional text above the top of the window, or below the bottom. If your buffer is small and it is all visible in the window, pos is ‘All’. Otherwise, it is ‘Top’ if you are looking at the beginning of the buffer, ‘Bot’ if you are looking at the end of the buffer, or ‘nn%’, where nn is the percentage of the buffer above the top of the window. With Size Indication mode, you can display the size of the buffer as well. See Optional Mode Line.
line is ‘L’ followed by the current line number of point. This is present when Line Number mode is enabled (which it normally is). You can optionally display the current column number too, by turning on Column Number mode (which is not enabled by default because it is somewhat slower). See Optional Mode Line.
major is the name of the major mode in effect in the buffer. At any time, each buffer is in one and only one of the possible major modes. The major modes available include Fundamental mode (the least specialized), Text mode, Lisp mode, C mode, Texinfo mode, and many others. See Major Modes, for details of how the modes differ and how to select one.
Some major modes display additional information after the major mode name. For example, Rmail buffers display the current message number and the total number of messages. Compilation buffers and Shell buffers display the status of the subprocess.
minor is a list of some of the minor modes that are turned on at the moment in the window's chosen buffer. For example, ‘Fill’ means that Auto Fill mode is on. ‘Abbrev’ means that Word Abbrev mode is on. ‘Ovwrt’ means that Overwrite mode is on. See Minor Modes, for more information. ‘Narrow’ means that the buffer being displayed has editing restricted to only a portion of its text. This is not really a minor mode, but is like one. See Narrowing. ‘Def’ means that a keyboard macro is being defined. See Keyboard Macros.
In addition, if Emacs is currently inside a recursive editing level, square brackets (‘[...]’) appear around the parentheses that surround the modes. If Emacs is in one recursive editing level within another, double square brackets appear, and so on. Since recursive editing levels affect Emacs globally, not just one buffer, the square brackets appear in every window's mode line or not in any of them. See Recursive Edit.
Non-windowing terminals can only show a single Emacs frame at a time (see Frames). On such terminals, the mode line displays the name of the selected frame, after ch. The initial frame's name is ‘F1’.
cs states the coding system used for the file you are editing. A dash indicates the default state of affairs: no code conversion, except for end-of-line translation if the file contents call for that. ‘=’ means no conversion whatsoever. Nontrivial code conversions are represented by various letters—for example, ‘1’ refers to ISO Latin-1. See Coding Systems, for more information. If you are using an input method, a string of the form ‘i>’ is added to the beginning of cs; i identifies the input method. (Some input methods show ‘+’ or ‘@’ instead of ‘>’.) See Input Methods.
When you are using a character-only terminal (not a window system), cs uses three characters to describe, respectively, the coding system for keyboard input, the coding system for terminal output, and the coding system used for the file you are editing.
When multibyte characters are not enabled, cs does not appear at all. See Enabling Multibyte.
The colon after cs can change to another string in certain circumstances. Emacs uses newline characters to separate lines in the buffer. Some files use different conventions for separating lines: either carriage-return linefeed (the MS-DOS convention) or just carriage-return (the Macintosh convention). If the buffer's file uses carriage-return linefeed, the colon changes to either a backslash (‘\’) or ‘(DOS)’, depending on the operating system. If the file uses just carriage-return, the colon indicator changes to either a forward slash (‘/’) or ‘(Mac)’. On some systems, Emacs displays ‘(Unix)’ instead of the colon even for files that use newline to separate lines.
You can customize the mode line display for each of the end-of-line
formats by setting each of the variables eol-mnemonic-unix,
eol-mnemonic-dos, eol-mnemonic-mac, and
eol-mnemonic-undecided to any string you find appropriate.
See Variables, for an explanation of how to set variables.
See Optional Mode Line, for features that add other handy information to the mode line, such as the size of the buffer, the current column number of point, the current time, and whether new mail for you has arrived.
The mode line is mouse-sensitive; when you move the mouse across various parts of it, Emacs displays help text to say what a click in that place will do. See Mode Line Mouse.
Each Emacs frame normally has a menu bar at the top which you can use to perform certain common operations. There's no need to list them here, as you can more easily see for yourself.
When you are using a window system, you can use the mouse to choose a command from the menu bar. An arrow pointing right, after the menu item, indicates that the item leads to a subsidiary menu; ‘...’ at the end means that the command will read arguments (further input from you) before it actually does anything.
To view the full command name and documentation for a menu item, type C-h k, and then select the menu bar with the mouse in the usual way (see Key Help).
On text-only terminals with no mouse, you can use the menu bar by
typing M-` or <F10> (these run the command
tmm-menubar). This command enters a mode in which you can select
a menu item from the keyboard. A provisional choice appears in the echo
area. You can use the up and down arrow keys to move through the
menu to different choices. When you have found the choice you want,
type <RET> to select it.
Each menu item also has an assigned letter or digit which designates that item; it is usually the initial of some word in the item's name. This letter or digit is separated from the item name by ‘=>’. You can type the item's letter or digit to select the item.
Some of the commands in the menu bar have ordinary key bindings as well; if so, the menu lists one equivalent key binding in parentheses after the item itself.
GNU Emacs uses an extension of the ASCII character set for keyboard input; it also accepts non-character input events including function keys and mouse button actions.
ASCII consists of 128 character codes. Some of these codes are assigned graphic symbols such as ‘a’ and ‘=’; the rest are control characters, such as Control-a (usually written C-a for short). C-a gets its name from the fact that you type it by holding down the <CTRL> key while pressing a.
Some ASCII control characters have special names, and most terminals have special keys you can type them with: for example, <RET>, <TAB>, <DEL> and <ESC>. The space character is usually referred to below as <SPC>, even though strictly speaking it is a graphic character whose graphic happens to be blank. Some keyboards have a key labeled “linefeed” which is an alias for C-j.
Emacs extends the ASCII character set with thousands more printing characters (see International), additional control characters, and a few more modifiers that can be combined with any character.
On ASCII terminals, there are only 32 possible control characters. These are the control variants of letters and ‘@[]\^_’. In addition, the shift key is meaningless with control characters: C-a and C-A are the same character, and Emacs cannot distinguish them.
But the Emacs character set has room for control variants of all printing characters, and for distinguishing between C-a and C-A. The X Window System makes it possible to enter all these characters. For example, C-- (that's Control-Minus) and C-5 are meaningful Emacs commands under X.
Another Emacs character-set extension is additional modifier bits. Only one modifier bit is commonly used; it is called Meta. Every character has a Meta variant; examples include Meta-a (normally written M-a, for short), M-A (not the same character as M-a, but those two characters normally have the same meaning in Emacs), M-<RET>, and M-C-a. For reasons of tradition, we usually write C-M-a rather than M-C-a; logically speaking, the order in which the modifier keys <CTRL> and <META> are mentioned does not matter.
Some terminals have a <META> key, and allow you to type Meta characters by holding this key down. Thus, Meta-a is typed by holding down <META> and pressing a. The <META> key works much like the <SHIFT> key. Such a key is not always labeled <META>, however, as this function is often a special option for a key with some other primary purpose. Sometimes it is labeled <ALT> or <EDIT>; on a Sun keyboard, it may have a diamond on it.
If there is no <META> key, you can still type Meta characters using two-character sequences starting with <ESC>. Thus, you can enter M-a by typing <ESC> a. You can enter C-M-a by typing <ESC> C-a. Unlike <META>, which modifies other characters, <ESC> is a separate character. You don't hold down <ESC> while typing the next character; instead, you press it and release it, then you enter the next character. <ESC> is allowed on terminals with <META> keys, too, in case you have formed a habit of using it.
The X Window System provides several other modifier keys that can be applied to any input character. These are called <SUPER>, <HYPER> and <ALT>. We write ‘s-’, ‘H-’ and ‘A-’ to say that a character uses these modifiers. Thus, s-H-C-x is short for Super-Hyper-Control-x. Not all X terminals actually provide keys for these modifier flags—in fact, many terminals have a key labeled <ALT> which is really a <META> key. The standard key bindings of Emacs do not include any characters with these modifiers. But you can assign them meanings of your own by customizing Emacs.
If your keyboard lacks one of these modifier keys, you can enter it using C-x @: C-x @ h adds the “hyper” flag to the next character, C-x @ s adds the “super” flag, and C-x @ a adds the “alt” flag. For instance, C-x @ h C-a is a way to enter Hyper-Control-a. (Unfortunately there is no way to add two modifiers by using C-x @ twice for the same character, because the first one goes to work on the C-x.)
Keyboard input includes keyboard keys that are not characters at all: for example function keys and arrow keys. Mouse buttons are also outside the gamut of characters. You can modify these events with the modifier keys <CTRL>, <META>, <SUPER>, <HYPER> and <ALT>, just like keyboard characters.
Input characters and non-character inputs are collectively called input events. See Input Events, for more information. If you are not doing Lisp programming, but simply want to redefine the meaning of some characters or non-character events, see Customization.
ASCII terminals cannot really send anything to the computer except ASCII characters. These terminals use a sequence of characters to represent each function key. But that is invisible to the Emacs user, because the keyboard input routines recognize these special sequences and convert them to function key events before any other part of Emacs gets to see them.
A key sequence (key, for short) is a sequence of input events that are meaningful as a unit—as “a single command.” Some Emacs command sequences are just one character or one event; for example, just C-f is enough to move forward one character in the buffer. But Emacs also has commands that take two or more events to invoke.
If a sequence of events is enough to invoke a command, it is a complete key. Examples of complete keys include C-a, X, <RET>, <NEXT> (a function key), <DOWN> (an arrow key), C-x C-f, and C-x 4 C-f. If it isn't long enough to be complete, we call it a prefix key. The above examples show that C-x and C-x 4 are prefix keys. Every key sequence is either a complete key or a prefix key.
Most single characters constitute complete keys in the standard Emacs command bindings. A few of them are prefix keys. A prefix key combines with the following input event to make a longer key sequence, which may itself be complete or a prefix. For example, C-x is a prefix key, so C-x and the next input event combine to make a two-event key sequence. Most of these key sequences are complete keys, including C-x C-f and C-x b. A few, such as C-x 4 and C-x r, are themselves prefix keys that lead to three-event key sequences. There's no limit to the length of a key sequence, but in practice people rarely use sequences longer than four events.
By contrast, you can't add more events onto a complete key. For example, the two-event sequence C-f C-k is not a key, because the C-f is a complete key in itself. It's impossible to give C-f C-k an independent meaning as a command. C-f C-k is two key sequences, not one.
All told, the prefix keys in Emacs are C-c, C-h, C-x, C-x <RET>, C-x @, C-x a, C-x n, C-x r, C-x v, C-x 4, C-x 5, C-x 6, <ESC>, M-o and M-g. (<F1> and <F2> are aliases for C-h and C-x 6.) But this list is not cast in concrete; it is just a matter of Emacs's standard key bindings. If you customize Emacs, you can make new prefix keys, or eliminate these. See Key Bindings.
If you do make or eliminate prefix keys, that changes the set of possible key sequences. For example, if you redefine C-f as a prefix, C-f C-k automatically becomes a key (complete, unless you define that too as a prefix). Conversely, if you remove the prefix definition of C-x 4, then C-x 4 f (or C-x 4 anything) is no longer a key.
Typing the help character (C-h or <F1>) after a prefix key displays a list of the commands starting with that prefix. There are a few prefix keys for which C-h does not work—for historical reasons, they have other meanings for C-h which are not easy to change. But <F1> should work for all prefix keys.
This manual is full of passages that tell you what particular keys do. But Emacs does not assign meanings to keys directly. Instead, Emacs assigns meanings to named commands, and then gives keys their meanings by binding them to commands.
Every command has a name chosen by a programmer. The name is usually
made of a few English words separated by dashes; for example,
next-line or forward-word. A command also has a
function definition which is a Lisp program; this is what makes
the command do what it does. In Emacs Lisp, a command is actually a
special kind of Lisp function; one which specifies how to read arguments
for it and call it interactively. For more information on commands and
functions, see What Is a Function. (The definition we use in this manual is
simplified slightly.)
The bindings between keys and commands are recorded in various tables called keymaps. See Keymaps.
When we say that “C-n moves down vertically one line” we are
glossing over a distinction that is irrelevant in ordinary use but is vital
in understanding how to customize Emacs. It is the command
next-line that is programmed to move down vertically. C-n has
this effect because it is bound to that command. If you rebind
C-n to the command forward-word then C-n will move
forward by words instead. Rebinding keys is a common method of
customization.
In the rest of this manual, we usually ignore this distinction to
keep things simple. We will often speak of keys like C-n as
commands, even though strictly speaking a key is bound to some
command. To give the information needed for customization, we state
the name of the command which really does the work in parentheses
after mentioning the key that runs it. For example, we will say that
“The command C-n (next-line) moves point vertically
down,” meaning that next-line is a command that moves
vertically down, and C-n is a key that is normally bound to it.
While we are on the subject of information for customization only,
it's a good time to tell you about variables. Often the
description of a command will say, “To change this, set the variable
mumble-foo.” A variable is a name used to remember a value.
Most of the variables documented in this manual exist just to facilitate
customization: some command or other part of Emacs examines the variable
and behaves differently according to the value that you set. Until you
are interested in customizing, you can ignore the information about
variables. When you are ready to be interested, read the basic
information on variables, and then the information on individual
variables will make sense. See Variables.
Text in Emacs buffers is a sequence of 8-bit bytes. Each byte can hold a single ASCII character. Both ASCII control characters (octal codes 000 through 037, and 0177) and ASCII printing characters (codes 040 through 0176) are allowed; however, non-ASCII control characters cannot appear in a buffer. The other modifier flags used in keyboard input, such as Meta, are not allowed in buffers either.
Some ASCII control characters serve special purposes in text, and have special names. For example, the newline character (octal code 012) is used in the buffer to end a line, and the tab character (octal code 011) is used for indenting to the next tab stop column (normally every 8 columns). See Text Display.
Non-ASCII printing characters can also appear in buffers. When multibyte characters are enabled, you can use any of the non-ASCII printing characters that Emacs supports. They have character codes starting at 256, octal 0400, and each one is represented as a sequence of two or more bytes. See International. Single-byte characters with codes 128 through 255 can also appear in multibyte buffers.
If you disable multibyte characters, then you can use only one alphabet of non-ASCII characters, but they all fit in one byte. They use codes 0200 through 0377. See Single-Byte Character Support.
The usual way to invoke Emacs is with the shell command emacs. Emacs clears the screen and then displays an initial help message and copyright notice. Some operating systems discard all type-ahead when Emacs starts up; they give Emacs no way to prevent this. Therefore, it is advisable to wait until Emacs clears the screen before typing your first editing command.
If you run Emacs from a shell window under the X Window System, run it in the background with emacs&. This way, Emacs does not tie up the shell window, so you can use that to run other shell commands while Emacs operates its own X windows. You can begin typing Emacs commands as soon as you direct your keyboard input to the Emacs frame.
When Emacs starts up, it creates a buffer named ‘*scratch*’.
That's the buffer you start out in. The ‘*scratch*’ buffer uses Lisp
Interaction mode; you can use it to type Lisp expressions and evaluate
them, or you can ignore that capability and simply doodle. (You can
specify a different major mode for this buffer by setting the variable
initial-major-mode in your init file. See Init File.)
It is possible to specify files to be visited, Lisp files to be loaded, and functions to be called, by giving Emacs arguments in the shell command line. See Emacs Invocation. But we don't recommend doing this. The feature exists mainly for compatibility with other editors.
Many other editors are designed to be started afresh each time you want to edit. You edit one file and then exit the editor. The next time you want to edit either another file or the same one, you must run the editor again. With these editors, it makes sense to use a command-line argument to say which file to edit.
But starting a new Emacs each time you want to edit a different file does not make sense. This would fail to take advantage of Emacs's ability to visit more than one file in a single editing session, and it would lose the other accumulated context, such as the kill ring, registers, undo history, and mark ring, that are useful for operating on multiple files.
The recommended way to use GNU Emacs is to start it only once, just after you log in, and do all your editing in the same Emacs session. Each time you want to edit a different file, you visit it with the existing Emacs, which eventually comes to have many files in it ready for editing. Usually you do not kill the Emacs until you are about to log out. See Files, for more information on visiting more than one file.
If you want to edit a file from another program and already have Emacs running, you can use the emacsclient program to open a file in the already running Emacs. See Emacs Server, for more information on editing files with Emacs from other programs.
There are two commands for exiting Emacs because there are three kinds of exiting: suspending Emacs, Iconifying Emacs, and killing Emacs.
Suspending means stopping Emacs temporarily and returning control to its parent process (usually a shell), allowing you to resume editing later in the same Emacs job, with the same buffers, same kill ring, same undo history, and so on. This is the usual way to exit Emacs when running on a text terminal.
Iconifying means replacing the Emacs frame with a small box somewhere on the screen. This is the usual way to exit Emacs when you're using a graphics terminal.
Killing Emacs means destroying the Emacs job. You can run Emacs again later, but you will get a fresh Emacs; there is no way to resume the same editing session after it has been killed.
suspend-emacs) or iconify a frame
(iconify-or-deiconify-frame).
save-buffers-kill-emacs).
To suspend or iconify Emacs, type C-z (suspend-emacs).
On text terminals, this suspends Emacs. On graphics terminals,
it iconifies the Emacs frame.
Suspending Emacs takes you back to the shell from which you invoked Emacs. You can resume Emacs with the shell command %emacs in most common shells. On systems that don't support suspending programs, C-z starts an inferior shell that communicates directly with the terminal. Emacs waits until you exit the subshell. (The way to do that is probably with C-d or exit, but it depends on which shell you use.) The only way on these systems to get back to the shell from which Emacs was run (to log out, for example) is to kill Emacs.
Suspending can fail if you run Emacs under a shell that doesn't
support suspending programs, even if the system itself does support
it. In such a case, you can set the variable cannot-suspend to
a non-nil value to force C-z to start an inferior shell.
(One might also describe Emacs's parent shell as “inferior” for
failing to support job control properly, but that is a matter of
taste.)
On graphics terminals, C-z has a different meaning: it runs
the command iconify-or-deiconify-frame, which temporarily
iconifies (or “minimizes”) the selected Emacs frame
(see Frames). Then you can use the window manager to get back to
a shell window.
To exit and kill Emacs, type C-x C-c
(save-buffers-kill-emacs). A two-character key is used for
this to make it harder to type by accident. This command first offers
to save any modified file-visiting buffers. If you do not save them
all, it asks for reconfirmation with yes before killing Emacs,
since any changes not saved will be lost forever. Also, if any
subprocesses are still running, C-x C-c asks for confirmation
about them, since killing Emacs will also kill the subprocesses.
If the value of the variable confirm-kill-emacs is
non-nil, C-x C-c assumes that its value is a predicate
function, and calls that function. If the result is non-nil, the
session is killed, otherwise Emacs continues to run. One convenient
function to use as the value of confirm-kill-emacs is the
function yes-or-no-p. The default value of
confirm-kill-emacs is nil.
There is no way to resume an Emacs session once you have killed it. You can, however, arrange for Emacs to record certain session information when you kill it, such as which files are visited, so that the next time you start Emacs it will try to visit the same files and so on. See Saving Emacs Sessions.
The operating system usually listens for certain special characters whose meaning is to kill or suspend the program you are running. This operating system feature is turned off while you are in Emacs. The meanings of C-z and C-x C-c as keys in Emacs were inspired by the use of C-z and C-c on several operating systems as the characters for stopping or killing a program, but that is their only relationship with the operating system. You can customize these keys to run any commands of your choice (see Keymaps).
We now give the basics of how to enter text, make corrections, and
save the text in a file. If this material is new to you, you might
learn it more easily by running the Emacs learn-by-doing tutorial. To
use the tutorial, run Emacs and type Control-h t
(help-with-tutorial).
To clear the screen and redisplay, type C-l (recenter).
To insert printing characters into the text you are editing, just type them. This inserts the characters you type into the buffer at the cursor (that is, at point; see Point). The cursor moves forward, and any text after the cursor moves forward too. If the text in the buffer is ‘FOOBAR’, with the cursor before the ‘B’, then if you type XX, you get ‘FOOXXBAR’, with the cursor still before the ‘B’.
To delete text you have just inserted, use the large key labeled <DEL>, <BACKSPACE> or <DELETE> which is a short distance above the <RET> or <ENTER> key. This is the key you normally use, outside Emacs, for erasing the last character that you typed. Regardless of the label on that key, Emacs thinks of it as <DEL>, and that's what we call it in this manual.
The <DEL> key deletes the character before the cursor. As a consequence, the cursor and all the characters after it move backwards. If you type a printing character and then type <DEL>, they cancel out.
On most computers, Emacs recognizes automatically which key ought to be <DEL>, and sets it up that way. But in some cases, especially with text-only terminals, you will need to tell Emacs which key to use for that purpose. If the large key not far above the <RET> or <ENTER> key doesn't delete backwards, you need to do this. See DEL Does Not Delete, for an explanation of how.
Most PC keyboards have both a <BACKSPACE> key a short ways above <RET> or <ENTER>, and a <DELETE> key elsewhere. On these keyboards, Emacs supports when possible the usual convention that the <BACKSPACE> key deletes backwards (it is <DEL>), while the <DELETE> key deletes “forwards,” deleting the character after point, the one underneath the cursor, like C-d (see below).
To end a line and start typing a new one, type <RET>. This inserts a newline character in the buffer. If point is in the middle of a line, the effect is to split the line. Typing <DEL> when the cursor is at the beginning of a line deletes the preceding newline, thus joining the line with the preceding line.
Emacs can split lines automatically when they become too long, if you turn on a special minor mode called Auto Fill mode. See Filling, for how to use Auto Fill mode.
If you prefer to have text characters replace (overwrite) existing text rather than shove it to the right, you can enable Overwrite mode, a minor mode. See Minor Modes.
Direct insertion works for printing characters and <SPC>, but other
characters act as editing commands and do not insert themselves. If you
need to insert a control character or a character whose code is above 200
octal, you must quote it by typing the character Control-q
(quoted-insert) first. (This character's name is normally written
C-q for short.) There are two ways to use C-q:
The use of octal sequences is disabled in ordinary non-binary Overwrite mode, to give you a convenient way to insert a digit instead of overwriting with it.
When multibyte characters are enabled, if you specify a code in the range 0200 through 0377 octal, C-q assumes that you intend to use some ISO 8859-n character set, and converts the specified code to the corresponding Emacs character code. See Enabling Multibyte. You select which of the ISO 8859 character sets to use through your choice of language environment (see Language Environments).
To use decimal or hexadecimal instead of octal, set the variable
read-quoted-char-radix to 10 or 16. If the radix is greater than
10, some letters starting with a serve as part of a character
code, just like digits.
A numeric argument to C-q specifies how many copies of the quoted character should be inserted (see Arguments).
Customization information: <DEL> in most modes runs the command
delete-backward-char; <RET> runs the command newline, and
self-inserting printing characters run the command self-insert,
which inserts whatever character was typed to invoke it. Some major modes
rebind <DEL> to other commands.
To do more than insert characters, you have to know how to move point (see Point). The simplest way to do this is with arrow keys, or by clicking the left mouse button where you want to move to.
There are also control and meta characters for cursor motion. Some are equivalent to the arrow keys (these date back to the days before terminals had arrow keys, and are usable on terminals which don't have them). Others do more sophisticated things.
move-beginning-of-line).
move-end-of-line).
forward-char). The right-arrow key
does the same thing.
backward-char). The left-arrow
key has the same effect.
forward-word).
backward-word).
next-line). This command
attempts to keep the horizontal position unchanged, so if you start in
the middle of one line, you end in the middle of the next. The
down-arrow key does the same thing.
previous-line). The up-arrow key
has the same effect.
move-to-window-line). Text does not move on the screen.
A numeric argument says which screen line to place point on. It counts
screen lines down from the top of the window (zero for the top line). A
negative argument counts lines from the bottom (−1 for the bottom
line).
beginning-of-buffer). With
numeric argument n, move to n/10 of the way from the top.
See Arguments, for more information on numeric arguments.
end-of-buffer).
scroll-up). This doesn't always move
point, but it is commonly used to do so. If your keyboard has a
<PAGEDOWN> or <PRIOR> key, it does the same thing.
Scrolling commands are further described in Scrolling.
scroll-down). This doesn't always move point, but
it is commonly used to do so. If your keyboard has a <PAGEUP> or
<NEXT> key, it does the same thing.
set-goal-column). Henceforth, those
commands always move to this column in each line moved into, or as
close as possible given the contents of the line. This goal column remains
in effect until canceled.
If you set the variable track-eol to a non-nil value,
then C-n and C-p, when starting at the end of the line, move
to the end of another line. Normally, track-eol is nil.
See Variables, for how to set variables such as track-eol.
C-n normally stops at the end of the buffer when you use it on
the last line of the buffer. But if you set the variable
next-line-add-newlines to a non-nil value, C-n on
the last line of a buffer creates an additional line at the end and
moves down onto it.
delete-backward-char).
delete-char).
kill-line).
kill-word).
backward-kill-word).
You already know about the <DEL> key which deletes the character before point (that is, before the cursor). Another key, Control-d (C-d for short), deletes the character after point (that is, the character that the cursor is on). This shifts the rest of the text on the line to the left. If you type C-d at the end of a line, it joins together that line and the next line.
To erase a larger amount of text, use the C-k key, which kills a line at a time. If you type C-k at the beginning or middle of a line, it kills all the text up to the end of the line. If you type C-k at the end of a line, it joins that line and the next line.
See Killing, for more flexible ways of killing text.
You can undo all the recent changes in the buffer text, up to a
certain point. Each buffer records changes individually, and the undo
command always applies to the current buffer. Usually each editing
command makes a separate entry in the undo records, but some commands
such as query-replace make many entries, and very simple commands
such as self-inserting characters are often grouped to make undoing less
tedious.
undo).
The command C-x u (or C-_ or C-/) is how you undo. The first time you give this command, it undoes the last change. Point moves back to where it was before the command that made the change.
Consecutive repetitions of C-_ or C-x u undo earlier and earlier changes, back to the limit of the undo information available. If all recorded changes have already been undone, the undo command displays an error message and does nothing.
Any command other than an undo command breaks the sequence of undo
commands. Starting from that moment, the previous undo commands become
ordinary changes that you can undo. Thus, to redo changes you have
undone, type C-f or any other command that will harmlessly break
the sequence of undoing, then type more undo commands. On the other
hand, if you want to ignore previous undo commands, use M-x
undo-only. This is like undo, but will not redo changes
you have just undone.
Ordinary undo applies to all changes made in the current buffer. You
can also perform selective undo, limited to the current region
(see Mark).
To do this, specify the region you want, then run the undo
command with a prefix argument (the value does not matter): C-u C-x
u or C-u C-_. This undoes the most recent change in the region.
To undo further changes in the same region, repeat the undo
command (no prefix argument is needed). In Transient Mark mode
(see Transient Mark), any use of undo when there is an
active region performs selective undo; you do not need a prefix
argument.
If you notice that a buffer has been modified accidentally, the easiest way to recover is to type C-_ repeatedly until the stars disappear from the front of the mode line. At this time, all the modifications you made have been canceled. Whenever an undo command makes the stars disappear from the mode line, it means that the buffer contents are the same as they were when the file was last read in or saved.
If you do not remember whether you changed the buffer deliberately, type C-_ once. When you see the last change you made undone, you will see whether it was an intentional change. If it was an accident, leave it undone. If it was deliberate, redo the change as described above.
Not all buffers record undo information. Buffers whose names start with spaces don't; these buffers are used internally by Emacs and its extensions to hold text that users don't normally look at or edit.
You cannot undo mere cursor motion; only changes in the buffer contents save undo information. However, some cursor motion commands set the mark, so if you use these commands from time to time, you can move back to the neighborhoods you have moved through by popping the mark ring (see Mark Ring).
When the undo information for a buffer becomes too large, Emacs
discards the oldest undo information from time to time (during garbage
collection). You can specify how much undo information to keep by
setting three variables: undo-limit, undo-strong-limit,
and undo-outer-limit. Their values are expressed in units of
bytes of space.
The variable undo-limit sets a soft limit: Emacs keeps undo
data for enough commands to reach this size, and perhaps exceed it,
but does not keep data for any earlier commands beyond that. Its
default value is 20000. The variable undo-strong-limit sets a
stricter limit: a previous command (not the most recent one) which
pushes the size past this amount is itself forgotten. The default
value of undo-strong-limit is 30000.
Regardless of the values of those variables, the most recent change
is never discarded unless it gets bigger than undo-outer-limit
(normally 3,000,000). At that point, Emacs discards the undo data and
warns you about it. This is the only situation in which you cannot
undo the last command. If this happens, you can increase the value of
undo-outer-limit to make it even less likely to happen in the
future. But if you didn't expect the command to create such large
undo data, then it is probably a bug and you should report it.
See Reporting Bugs.
The reason the undo command has three key bindings, C-x
u, C-_ and C-/, is that it is worthy of a
single-character key, but C-x u is more straightforward for
beginners to type.
The commands described above are sufficient for creating and altering text in an Emacs buffer; the more advanced Emacs commands just make things easier. But to keep any text permanently you must put it in a file. Files are named units of text which are stored by the operating system for you to retrieve later by name. To look at or use the contents of a file in any way, including editing the file with Emacs, you must specify the file name.
Consider a file named /usr/rms/foo.c. In Emacs, to begin editing this file, type
C-x C-f /usr/rms/foo.c <RET>
Here the file name is given as an argument to the command C-x
C-f (find-file). That command uses the minibuffer to
read the argument, and you type <RET> to terminate the argument
(see Minibuffer).
Emacs obeys the command by visiting the file: creating a buffer,
copying the contents of the file into the buffer, and then displaying
the buffer for you to edit. If you alter the text, you can save
the new text in the file by typing C-x C-s (save-buffer).
This makes the changes permanent by copying the altered buffer contents
back into the file /usr/rms/foo.c. Until you save, the changes
exist only inside Emacs, and the file foo.c is unaltered.
To create a file, just visit the file with C-x C-f as if it already existed. This creates an empty buffer in which you can insert the text you want to put in the file. The file is actually created when you save this buffer with C-x C-s.
Of course, there is a lot more to learn about using files. See Files.
If you forget what a key does, you can find out with the Help
character, which is C-h (or <F1>, which is an alias for
C-h). Type C-h k followed by the key you want to know
about; for example, C-h k C-n tells you all about what C-n
does. C-h is a prefix key; C-h k is just one of its
subcommands (the command describe-key). The other subcommands of
C-h provide different kinds of help. Type C-h twice to get
a description of all the help facilities. See Help.
Here are special commands and techniques for putting in and taking out blank lines.
open-line).
delete-blank-lines).
When you want to insert a new line of text before an existing line, you
can do it by typing the new line of text, followed by <RET>.
However, it may be easier to see what you are doing if you first make a
blank line and then insert the desired text into it. This is easy to do
using the key C-o (open-line), which inserts a newline
after point but leaves point in front of the newline. After C-o,
type the text for the new line. C-o F O O has the same effect as
F O O <RET>, except for the final location of point.
You can make several blank lines by typing C-o several times, or by giving it a numeric argument to tell it how many blank lines to make. See Arguments, for how. If you have a fill prefix, the C-o command inserts the fill prefix on the new line, when you use it at the beginning of a line. See Fill Prefix.
The easy way to get rid of extra blank lines is with the command
C-x C-o (delete-blank-lines). C-x C-o in a run of
several blank lines deletes all but one of them. C-x C-o on a
solitary blank line deletes that blank line. When point is on a
nonblank line, C-x C-o deletes any blank lines following that
nonblank line.
If you add too many characters to one line without breaking it with <RET>, the line grows to occupy two (or more) lines on the screen. On graphical displays, Emacs indicates line wrapping with small bent arrows in the fringes to the left and right of the window. On text-only terminals, Emacs displays a ‘\’ character at the right margin of a screen line if it is not the last in its text line. This ‘\’ character says that the following screen line is not really a distinct line in the text, just a continuation of a line too long to fit the screen. Continuation is also called line wrapping.
When line wrapping occurs before a character that is wider than one column, some columns at the end of the previous screen line may be “empty.” In this case, Emacs displays additional ‘\’ characters in the “empty” columns, just before the ‘\’ character that indicates continuation.
Sometimes it is nice to have Emacs insert newlines automatically when a line gets too long. Continuation on the screen does not do that. Use Auto Fill mode (see Filling) if that's what you want.
As an alternative to continuation, Emacs can display long lines by truncation. This means that all the characters that do not fit in the width of the screen or window do not appear at all. ‘$’ in the last column or a small straight arrow in the fringe to the right of the window indicates a truncated line.
See Display Custom, for more information about line truncation, and other variables that affect how text is displayed.
Here are commands to get information about the size and position of parts of the buffer, and to count lines.
count-lines-region).
See Mark, for information about the region.
what-cursor-position).
M-x what-line computes the current line number and displays it
in the echo area. You can also see the current line number in the
mode line; see Mode Line. If you narrow the buffer, then the
line number in the mode line is relative to the accessible portion
(see Narrowing). By contrast, what-line shows both the
line number relative to the narrowed region and the line number
relative to the whole buffer.
M-x what-page counts pages from the beginning of the file, and counts lines within the page, showing both numbers in the echo area. See Pages.
While on this subject, we might as well mention M-= (count-lines-region),
which displays the number of lines in the region (see Mark).
See Pages, for the command C-x l which counts the lines in the
current page.
The command C-x = (what-cursor-position) shows what
column the cursor is in, and other miscellaneous information about
point and the character after it. It displays a line in the echo area
that looks like this:
Char: c (99, #o143, #x63) point=28062 of 36168 (78%) column=53
The four values after ‘Char:’ describe the character that follows point, first by showing it and then by giving its character code in decimal, octal and hex. For a non-ASCII multibyte character, these are followed by ‘file’ and the character's representation, in hex, in the buffer's coding system, if that coding system encodes the character safely and with a single byte (see Coding Systems). If the character's encoding is longer than one byte, Emacs shows ‘file ...’.
However, if the character displayed is in the range 0200 through 0377 octal, it may actually stand for an invalid UTF-8 byte read from a file. In Emacs, that byte is represented as a sequence of 8-bit characters, but all of them together display as the original invalid byte, in octal code. In this case, C-x = shows ‘part of display ...’ instead of ‘file’.
‘point=’ is followed by the position of point expressed as a character count. The front of the buffer counts as position 1, one character later as 2, and so on. The next, larger, number is the total number of characters in the buffer. Afterward in parentheses comes the position expressed as a percentage of the total size.
‘column=’ is followed by the horizontal position of point, in columns from the left edge of the window.
If the buffer has been narrowed, making some of the text at the beginning and the end temporarily inaccessible, C-x = displays additional text describing the currently accessible range. For example, it might display this:
Char: C (67, #o103, #x43) point=252 of 889 (28%) <231-599> column=0
where the two extra numbers give the smallest and largest character position that point is allowed to assume. The characters between those two positions are the accessible ones. See Narrowing.
If point is at the end of the buffer (or the end of the accessible part), the C-x = output does not describe a character after point. The output might look like this:
point=36169 of 36168 (EOB) column=0
C-u C-x = displays the following additional information about a character.
ascii character set.
Here's an example showing the Latin-1 character A with grave accent,
in a buffer whose coding system is iso-latin-1, whose
terminal coding system is iso-latin-1 (so the terminal actually
displays the character as ‘À’), and which has font-lock-mode
(see Font Lock) enabled:
character: À (2240, #o4300, #x8c0, U+00C0)
charset: [latin-iso8859-1]
(Right-Hand Part of Latin Alphabet 1...
code point: [64]
syntax: w which means: word
category: l:Latin
to input: type "`A" with [latin-1-prefix]
buffer code: #x81 #xC0
file code: ESC #x2C #x41 #x40 (encoded by coding system iso-2022-7bit)
display: terminal code #xC0
There are text properties here:
fontified t
In mathematics and computer usage, the word argument means “data provided to a function or operation.” You can give any Emacs command a numeric argument (also called a prefix argument). Some commands interpret the argument as a repetition count. For example, C-f with an argument of ten moves forward ten characters instead of one. With these commands, no argument is equivalent to an argument of one. Negative arguments tell most such commands to move or act in the opposite direction.
If your terminal keyboard has a <META> key (labeled <ALT> on PC keyboards), the easiest way to specify a numeric argument is to type digits and/or a minus sign while holding down the <META> key. For example,
M-5 C-n
would move down five lines. The characters Meta-1, Meta-2,
and so on, as well as Meta--, do this because they are keys bound
to commands (digit-argument and negative-argument) that
are defined to contribute to an argument for the next command.
Meta-- without digits normally means −1. Digits and
- modified with Control, or Control and Meta, also specify numeric
arguments.
Another way of specifying an argument is to use the C-u
(universal-argument) command followed by the digits of the
argument. With C-u, you can type the argument digits without
holding down modifier keys; C-u works on all terminals. To type a
negative argument, type a minus sign after C-u. Just a minus sign
without digits normally means −1.
C-u followed by a character which is neither a digit nor a minus sign has the special meaning of “multiply by four.” It multiplies the argument for the next command by four. C-u twice multiplies it by sixteen. Thus, C-u C-u C-f moves forward sixteen characters. This is a good way to move forward “fast,” since it moves about 1/5 of a line in the usual size screen. Other useful combinations are C-u C-n, C-u C-u C-n (move down a good fraction of a screen), C-u C-u C-o (make “a lot” of blank lines), and C-u C-k (kill four lines).
Some commands care only about whether there is an argument, and not about
its value. For example, the command M-q (fill-paragraph) with
no argument fills text; with an argument, it justifies the text as well.
(See Filling, for more information on M-q.) Plain C-u is a
handy way of providing an argument for such commands.
Some commands use the value of the argument as a repeat count, but do
something peculiar when there is no argument. For example, the command
C-k (kill-line) with argument n kills n lines,
including their terminating newlines. But C-k with no argument is
special: it kills the text up to the next newline, or, if point is right at
the end of the line, it kills the newline itself. Thus, two C-k
commands with no arguments can kill a nonblank line, just like C-k
with an argument of one. (See Killing, for more information on
C-k.)
A few commands treat a plain C-u differently from an ordinary argument. A few others may treat an argument of just a minus sign differently from an argument of −1. These unusual cases are described when they come up; they are always for reasons of convenience of use of the individual command, and they are documented in the command's documentation string.
You can use a numeric argument to insert multiple copies of a character. This is straightforward unless the character is a digit; for example, C-u 6 4 a inserts 64 copies of the character ‘a’. But this does not work for inserting digits; C-u 6 4 1 specifies an argument of 641, rather than inserting anything. To separate the digit to insert from the argument, type another C-u; for example, C-u 6 4 C-u 1 does insert 64 copies of the character ‘1’.
We use the term “prefix argument” as well as “numeric argument” to emphasize that you type the argument before the command, and to distinguish these arguments from minibuffer arguments that come after the command.
Many simple commands, such as those invoked with a single key or with M-x command-name <RET>, can be repeated by invoking them with a numeric argument that serves as a repeat count (see Arguments). However, if the command you want to repeat prompts for some input, or uses a numeric argument in another way, repetition using a numeric argument might be problematical.
The command C-x z (repeat) provides another way to repeat
an Emacs command many times. This command repeats the previous Emacs
command, whatever that was. Repeating a command uses the same arguments
that were used before; it does not read new arguments each time.
To repeat the command more than once, type additional z's: each z repeats the command one more time. Repetition ends when you type a character other than z, or press a mouse button.
For example, suppose you type C-u 2 0 C-d to delete 20 characters. You can repeat that command (including its argument) three additional times, to delete a total of 80 characters, by typing C-x z z z. The first C-x z repeats the command once, and each subsequent z repeats it once again.
The minibuffer is the facility used by Emacs commands to read arguments more complicated than a single number. Minibuffer arguments can be file names, buffer names, Lisp function names, Emacs command names, Lisp expressions, and many other things, depending on the command reading the argument. You can use the usual Emacs editing commands in the minibuffer to edit the argument text.
When the minibuffer is in use, it appears in the echo area, and the terminal's cursor moves there. The beginning of the minibuffer line displays a prompt in a special color, to say what kind of input you should supply and how it will be used. Often this prompt is derived from the name of the command that the argument is for. The prompt normally ends with a colon.
Sometimes a default argument appears in parentheses before the colon; it too is part of the prompt. The default will be used as the argument value if you enter an empty argument (that is, just type <RET>). For example, commands that read buffer names always show a default, which is the name of the buffer that will be used if you type just <RET>.
The simplest way to enter a minibuffer argument is to type the text you want, terminated by <RET> which exits the minibuffer. You can cancel the command that wants the argument, and get out of the minibuffer, by typing C-g.
Since the minibuffer uses the screen space of the echo area, it can conflict with other ways Emacs customarily uses the echo area. Here is how Emacs handles such conflicts:
Sometimes the minibuffer starts out with text in it. For example, when you are supposed to give a file name, the minibuffer starts out containing the default directory, which ends with a slash. This is to inform you which directory the file will be found in if you do not specify a directory.
For example, the minibuffer might start out with these contents:
Find File: /u2/emacs/src/
where ‘Find File: ’ is the prompt. Typing buffer.c as input specifies the file /u2/emacs/src/buffer.c. To find files in nearby directories, use ..; thus, if you type ../lisp/simple.el, you will get the file named /u2/emacs/lisp/simple.el. Alternatively, you can kill with M-<DEL> the directory names you don't want (see Words).
If you don't want any of the default, you can kill it with C-a C-k. But you don't need to kill the default; you can simply ignore it. Insert an absolute file name, one starting with a slash or a tilde, after the default directory. For example, to specify the file /etc/termcap, just insert that name, giving these minibuffer contents:
Find File: /u2/emacs/src//etc/termcap
GNU Emacs gives a special meaning to a double slash (which is not
normally a useful thing to write): it means, “ignore everything
before the second slash in the pair.” Thus, ‘/u2/emacs/src/’ is
ignored in the example above, and you get the file
/etc/termcap. The ignored part of the file name is dimmed if
the terminal allows it; to disable this, turn off
file-name-shadow-mode minor mode.
If you set insert-default-directory to nil, the default
directory is not inserted in the minibuffer. This way, the minibuffer
starts out empty. But the name you type, if relative, is still
interpreted with respect to the same default directory.
The minibuffer is an Emacs buffer (albeit a peculiar one), and the usual Emacs commands are available for editing the text of an argument you are entering.
Since <RET> in the minibuffer is defined to exit the minibuffer, you can't use it to insert a newline in the minibuffer. To do that, type C-o or C-q C-j. (On text terminals, newline is really the ASCII character control-J.)
The minibuffer has its own window which always has space on the screen but acts as if it were not there when the minibuffer is not in use. When the minibuffer is in use, its window is just like the others; you can switch to another window with C-x o, edit text in other windows and perhaps even visit more files, before returning to the minibuffer to submit the argument. You can kill text in another window, return to the minibuffer window, and then yank the text to use it in the argument. See Windows.
There are some restrictions on the use of the minibuffer window, however. You cannot switch buffers in it—the minibuffer and its window are permanently attached. Also, you cannot split or kill the minibuffer window. But you can make it taller in the normal fashion with C-x ^.
The minibuffer window expands vertically as necessary to hold the
text that you put in the minibuffer. If resize-mini-windows is
t (the default), the window is always resized to fit the size
of the text it displays. If its value is the symbol grow-only,
the window grows when the size of displayed text increases, but
shrinks (back to the normal size) only when the minibuffer becomes
inactive. If its value is nil, you have to adjust the height
yourself.
The variable max-mini-window-height controls the maximum
height for resizing the minibuffer window: a floating-point number
specifies a fraction of the frame's height; an integer specifies the
maximum number of lines; nil means do not resize the minibuffer
window automatically. The default value is 0.25.
If, while in the minibuffer, you issue a command that displays help text of any sort in another window, you can use the C-M-v command while in the minibuffer to scroll the help text. (M-<PAGEUP> and M-<PAGEDOWN> also operate on that help text.) This lasts until you exit the minibuffer. This feature is especially useful when you display a buffer listing possible completions. See Other Window.
Emacs normally disallows most commands that use the minibuffer while
the minibuffer is active. This rule is to prevent recursive minibuffers
from confusing novice users. If you want to be able to use such
commands in the minibuffer, set the variable
enable-recursive-minibuffers to a non-nil value.
For certain kinds of arguments, you can use completion to enter the argument value. Completion means that you type part of the argument, then Emacs visibly fills in the rest, or as much as can be determined from the part you have typed.
When completion is available, certain keys—<TAB>, <RET>, and <SPC>—are rebound to complete the text in the minibuffer before point into a longer string that it stands for, by matching it against a set of completion alternatives provided by the command reading the argument. ? is defined to display a list of possible completions of what you have inserted.
For example, when M-x uses the minibuffer to read the name of a command, it provides a list of all available Emacs command names to complete against. The completion keys match the minibuffer text against all the command names, find any additional name characters implied by the ones already present in the minibuffer, and add those characters to the ones you have given. This is what makes it possible to type M-x ins <SPC> b <RET> instead of M-x insert-buffer <RET> (for example). (<SPC> does not do completion in reading file names, because it is common to use spaces in file names on some systems.)
Case is normally significant in completion, because it is significant in most of the names that you can complete (buffer names, file names and command names). Thus, ‘fo’ does not complete to ‘Foo’. Completion does ignore case distinctions for certain arguments in which case does not matter.
Completion acts only on the text before point. If there is text in the minibuffer after point—i.e., if you move point backward after typing some text into the minibuffer—it remains unchanged.
A concrete example may help here. If you type M-x au <TAB>,
the <TAB> looks for alternatives (in this case, command names) that
start with ‘au’. There are several, including
auto-fill-mode and auto-save-mode—but they are all the
same as far as auto-, so the ‘au’ in the minibuffer changes
to ‘auto-’.
If you type <TAB> again immediately, there are multiple possibilities for the very next character—it could be any of ‘cfilrs’—so no more characters are added; instead, <TAB> displays a list of all possible completions in another window.
If you go on to type f <TAB>, this <TAB> sees
‘auto-f’. The only command name starting this way is
auto-fill-mode, so completion fills in the rest of that. You now
have ‘auto-fill-mode’ in the minibuffer after typing just au
<TAB> f <TAB>. Note that <TAB> has this effect because in
the minibuffer it is bound to the command minibuffer-complete
when completion is available.
Here is a list of the completion commands defined in the minibuffer when completion is available.
minibuffer-complete).
minibuffer-complete-word). <SPC> for completion is
not available when entering a file name, since some users often put
spaces in filenames.
minibuffer-complete-and-exit). See Strict Completion.
minibuffer-completion-help).
<SPC> completes much like <TAB>, but never goes beyond the
next hyphen or space. If you have ‘auto-f’ in the minibuffer and
type <SPC>, it finds that the completion is ‘auto-fill-mode’,
but it stops completing after ‘fill-’. This gives
‘auto-fill-’. Another <SPC> at this point completes all the
way to ‘auto-fill-mode’. The command that implements this
behavior is called minibuffer-complete-word.
Here are some commands you can use to choose a completion from a window that displays a list of completions:
mouse-choose-completion).
You normally use this command while point is in the minibuffer, but you
must click in the list of completions, not in the minibuffer itself.
switch-to-completions). This paves the way for using the
commands below. (Selecting that window in the usual ways has the same
effect, but this way is more convenient.)
choose-completion). To
use this command, you must first switch windows to the window that shows
the list of completions.
next-completion).
previous-completion).
There are three different ways that <RET> can work in completing minibuffers, depending on how the argument will be used.
Cautious completion is used for reading file names for files that must already exist.
The completion commands display a list of all possible completions in a window whenever there is more than one possibility for the very next character. Also, typing ? explicitly requests such a list. If the list of completions is long, you can scroll it with C-M-v (see Other Window).
When completion is done on file names, certain file names are usually
ignored. The variable completion-ignored-extensions contains a
list of strings; a file whose name ends in any of those strings is
ignored as a possible completion. The standard value of this variable
has several elements including ".o", ".elc", ".dvi"
and "~". The effect is that, for example, ‘foo’ can
complete to ‘foo.c’ even though ‘foo.o’ exists as well.
However, if all the possible completions end in “ignored”
strings, then they are not ignored. Ignored extensions do not apply to
lists of completions—those always mention all possible completions.
If an element of the list in completion-ignored-extensions ends
in a slash /, it indicates a subdirectory that should be ignored
when completing file names. (Elements of
completion-ignored-extensions which do not end in a slash are
never considered when a completion candidate is a directory; thus,
completion returns directories whose names end in .elc even
though there's an element ".elc" in the list.)
Normally, a completion command that cannot determine even one
additional character automatically displays a list of all possible
completions. If the variable completion-auto-help is set to
nil, this automatic display is disabled, so you must type
? to display the list of completions.
Partial Completion mode implements a more powerful kind of
completion that can complete multiple words in parallel. For example,
it can complete the command name abbreviation p-b into
print-buffer, because no other command starts with two words
whose initials are ‘p’ and ‘b’.
Partial completion of directories in file names uses ‘*’ to indicate the places for completion; thus, /u*/b*/f* might complete to /usr/bin/foo.
To enable this mode, use the command M-x
partial-completion-mode, or customize the variable
partial-completion-mode. This binds the partial completion
commands to <TAB>, <SPC>, <RET>, and ?. The usual
completion commands are available on M-<TAB> (or
C-M-i), M-<SPC>, M-<RET> and M-?.
Another feature of Partial Completion mode is to extend
find-file so that ‘<include>’ stands for the
file named include in some directory in the path
PC-include-file-path. If you set PC-disable-includes to
non-nil, this feature is disabled.
Icomplete mode presents a constantly-updated display that tells you what completions are available for the text you've entered so far. The command to enable or disable this minor mode is M-x icomplete-mode.
Every argument that you enter with the minibuffer is saved on a minibuffer history list so that you can use it again later in another argument. Special commands load the text of an earlier argument in the minibuffer. They discard the old minibuffer contents, so you can think of them as moving through the history of previous arguments.
previous-history-element).
next-history-element).
previous-matching-history-element).
next-matching-history-element).
The simplest way to reuse the saved arguments in the history list is
to move through the history list one element at a time. While in the
minibuffer, use M-p or up-arrow
(previous-history-element) to “move to” the next earlier
minibuffer input, and use M-n or down-arrow
(next-history-element) to “move to” the next later input.
These commands don't move the cursor, they bring different saved
strings into the minibuffer. But you can think of them as “moving”
through the history list.
The previous input that you fetch from the history entirely replaces the contents of the minibuffer. To use it as the argument, exit the minibuffer as usual with <RET>. You can also edit the text before you reuse it; this does not change the history element that you “moved” to, but your new argument does go at the end of the history list in its own right.
For many minibuffer arguments there is a “default” value. In some cases, the minibuffer history commands know the default value. Then you can insert the default value into the minibuffer as text by using M-n to move “into the future” in the history. Eventually we hope to make this feature available whenever the minibuffer has a default value.
There are also commands to search forward or backward through the
history; they search for history elements that match a regular
expression that you specify with the minibuffer. M-r
(previous-matching-history-element) searches older elements in
the history, while M-s (next-matching-history-element)
searches newer elements. By special dispensation, these commands can
use the minibuffer to read their arguments even though you are already
in the minibuffer when you issue them. As with incremental searching,
an upper-case letter in the regular expression makes the search
case-sensitive (see Search Case).
All uses of the minibuffer record your input on a history list, but there are separate history lists for different kinds of arguments. For example, there is a list for file names, used by all the commands that read file names. (As a special feature, this history list records the absolute file name, no more and no less, even if that is not how you entered the file name.)
There are several other very specific history lists, including one for
command names read by M-x, one for buffer names, one for arguments
of commands like query-replace, and one for compilation commands
read by compile. Finally, there is one “miscellaneous” history
list that most minibuffer arguments use.
The variable history-length specifies the maximum length of a
minibuffer history list; once a list gets that long, the oldest element
is deleted each time an element is added. If the value of
history-length is t, though, there is no maximum length
and elements are never deleted.
The variable history-delete-duplicates specifies whether to
delete duplicates in history. If the value of history-delete-duplicates
is t, that means when adding a new history element, all
previous identical elements are deleted.
Every command that uses the minibuffer at least once is recorded on a special history list, together with the values of its arguments, so that you can repeat the entire command. In particular, every use of M-x is recorded there, since M-x uses the minibuffer to read the command name.
repeat-complex-command).
C-x <ESC> <ESC> is used to re-execute a recent minibuffer-using command. With no argument, it repeats the last such command. A numeric argument specifies which command to repeat; one means the last one, and larger numbers specify earlier ones.
C-x <ESC> <ESC> works by turning the previous command into a Lisp expression and then entering a minibuffer initialized with the text for that expression. If you type just <RET>, the command is repeated as before. You can also change the command by editing the Lisp expression. Whatever expression you finally submit is what will be executed. The repeated command is added to the front of the command history unless it is identical to the most recently executed command already there.
Even if you don't understand Lisp syntax, it will probably be obvious which command is displayed for repetition. If you do not change the text, it will repeat exactly as before.
Once inside the minibuffer for C-x <ESC> <ESC>, you can use the minibuffer history commands (M-p, M-n, M-r, M-s; see Minibuffer History) to move through the history list of saved entire commands. After finding the desired previous command, you can edit its expression as usual and then resubmit it by typing <RET> as usual.
Incremental search does not, strictly speaking, use the minibuffer,
but it does something similar. Although it behaves like a complex command,
it normally does not appear in the history list for C-x
<ESC> <ESC>. You can make it appear in the history by
setting isearch-resume-in-command-history to a non-nil
value. See Incremental Search.
The list of previous minibuffer-using commands is stored as a Lisp
list in the variable command-history. Each element is a Lisp
expression which describes one command and its arguments. Lisp programs
can re-execute a command by calling eval with the
command-history element.
Every Emacs command has a name that you can use to run it. Commands that are used often, or that must be quick to type, are also bound to keys—short sequences of characters—for convenient use. You can run them by name if you don't remember the keys. Other Emacs commands that do not need to be quick are not bound to keys; the only way to run them is by name. See Key Bindings, for the description of how to bind commands to keys.
By convention, a command name consists of one or more words,
separated by hyphens; for example, auto-fill-mode or
manual-entry. The use of English words makes the command name
easier to remember than a key made up of obscure characters, even
though it is more characters to type.
The way to run a command by name is to start with M-x, type the command name, and finish it with <RET>. M-x uses the minibuffer to read the command name. <RET> exits the minibuffer and runs the command. The string ‘M-x’ appears at the beginning of the minibuffer as a prompt to remind you to enter the name of a command to be run. See Minibuffer, for full information on the features of the minibuffer.
You can use completion to enter the command name. For example, you
can invoke the command forward-char by name by typing either
M-x forward-char <RET>
or
M-x forw <TAB> c <RET>
Note that forward-char is the same command that you invoke with
the key C-f. You can run any Emacs command by name using
M-x, whether or not any keys are bound to it.
If you type C-g while the command name is being read, you cancel the M-x command and get out of the minibuffer, ending up at command level.
To pass a numeric argument to the command you are invoking with M-x, specify the numeric argument before the M-x. M-x passes the argument along to the command it runs. The argument value appears in the prompt while the command name is being read.
If the command you type has a key binding of its own, Emacs mentions
this in the echo area. For example, if you type M-x
forward-word, the message says that you can run the same command more
easily by typing M-f. You can turn off these messages by
setting suggest-key-bindings to nil.
Normally, when describing in this manual a command that is run by name, we omit the <RET> that is needed to terminate the name. Thus we might speak of M-x auto-fill-mode rather than M-x auto-fill-mode <RET>. We mention the <RET> only when there is a need to emphasize its presence, such as when we show the command together with following arguments.
M-x works by running the command
execute-extended-command, which is responsible for reading the
name of another command and invoking it.
Emacs provides extensive help features accessible through a single character, C-h. C-h is a prefix key that is used for commands that display documentation. The characters that you can type after C-h are called help options. One help option is C-h; that is how you ask for help about using C-h. To cancel, type C-g. The function key <F1> is equivalent to C-h.
C-h C-h (help-for-help) displays a list of the possible
help options, each with a brief description. Before you type a help
option, you can use <SPC> or <DEL> to scroll through the list.
C-h or <F1> means “help” in various other contexts as well. After a prefix key, it displays a list of the alternatives that can follow the prefix key. (A few prefix keys don't support C-h, because they define other meanings for it, but they all support <F1>.)
Most help buffers use a special major mode, Help mode, which lets you scroll conveniently with <SPC> and <DEL>. It also offers hyperlinks to URLs and further help regarding cross-referenced names, Info nodes, customization buffers and the like. See Help Mode.
If you are looking for a certain feature, but don't know where exactly it is documented, and aren't sure of the name of a related command or variable, we recommend trying these methods. Usually it is best to start with an apropos command, then try searching the manual index, then finally look in the FAQ and the package keywords.
To find the documentation of a key sequence or a menu item, type C-h K and then type that key sequence or select the menu item. This looks up the description of the command invoked by the key or the menu in the appropriate manual (not necessarily the Emacs manual). Likewise, use C-h F for reading documentation of a command.
Here is a summary of the Emacs interactive help commands. See Help Files, for other help commands that just display a pre-written file of information.
apropos-command; see Apropos).
describe-bindings).
describe-key-briefly). Here c stands for “character.”
For more extensive information on key, use C-h k.
apropos-documentation).
*Messages* buffer
(view-echo-area-messages).
describe-function). Since commands are Lisp functions,
a command name may be used.
info).
The complete Emacs manual is available on-line in Info.
describe-key).
view-lossage).
describe-mode).
finder-by-keyword).
describe-syntax). See Syntax.
help-with-tutorial).
describe-variable).
where-is).
describe-coding-system).
describe-input-method).
describe-language-environment).
Info-goto-emacs-command-node).
Info-goto-emacs-key-command-node).
info-lookup-symbol).
display-local-help).
The most basic C-h options are C-h c
(describe-key-briefly) and C-h k (describe-key).
C-h c key displays in the echo area the name of the command
that key is bound to. For example, C-h c C-f displays
‘forward-char’. Since command names are chosen to describe what
the commands do, this is a good way to get a very brief description of
what key does.
C-h k key is similar but gives more information: it displays the documentation string of the command as well as its name. This is too big for the echo area, so a window is used for the display.
C-h c and C-h k work for any sort of key sequences, including function keys and mouse events.
C-h w command <RET> tells you what keys are bound to
command. It displays a list of the keys in the echo area. If it
says the command is not on any key, you must use M-x to run it.
C-h w runs the command where-is.
C-h f (describe-function) reads the name of a Lisp function
using the minibuffer, then displays that function's documentation string
in a window. Since commands are Lisp functions, you can use this to get
the documentation of a command that you know by name. For example,
C-h f auto-fill-mode <RET>
displays the documentation of auto-fill-mode. This is the only
way to get the documentation of a command that is not bound to any key
(one which you would normally run using M-x).
C-h f is also useful for Lisp functions that you are planning
to use in a Lisp program. For example, if you have just written the
expression (make-vector len) and want to check that you are
using make-vector properly, type C-h f make-vector
<RET>. Because C-h f allows all function names, not just
command names, you may find that some of your favorite completion
abbreviations that work in M-x don't work in C-h f. An
abbreviation may be unique among command names, yet fail to be unique
when other function names are allowed.
The default function name for C-h f to describe, if you type
just <RET>, is the name of the function called by the innermost Lisp
expression in the buffer around point, provided that is a valid,
defined Lisp function name. For example, if point is located following
the text ‘(make-vector (car x)’, the innermost list containing
point is the one that starts with ‘(make-vector’, so the default is
to describe the function make-vector.
C-h f is often useful just to verify that you have the right spelling for the function name. If C-h f mentions a name from the buffer as the default, that name must be defined as a Lisp function. If that is all you want to know, just type C-g to cancel the C-h f command, then go on editing.
C-h v (describe-variable) is like C-h f but describes
Lisp variables instead of Lisp functions. Its default is the Lisp symbol
around or before point, but only if that is the name of a known Lisp
variable. See Variables.
Help buffers describing Emacs variables and functions normally have hyperlinks to the definition, if you have the source files installed. (See Hyperlinking.) If you know Lisp (or C), this provides the ultimate documentation. If you don't know Lisp, you should learn it. If you are just using Emacs, treating Emacs as an object (file), then you don't really love it. For true intimacy with your editor, you need to read the source code.
A more sophisticated sort of question to ask is, “What are the commands for working with files?” The apropos commands ask such questions—they look for things whose names match an apropos pattern, which means either a word, a list of words, or a regular expression. Each apropos command displays a list of matching items in a special buffer.
To find the commands that work on files, type C-h a file
<RET>. This displays a list of all command names that contain
‘file’, including copy-file, find-file, and so on.
With each command name appears a brief description of how to use the
command, and what keys you can currently invoke it with. For example,
it would say that you can invoke find-file by typing C-x
C-f. The a in C-h a stands for “Apropos”; C-h a
runs the command apropos-command. This command normally checks
only commands (interactive functions); if you specify a prefix
argument, it checks noninteractive functions as well.
If you want more information about a function definition, variable or symbol property listed in the Apropos buffer, you can click on it with Mouse-1 or Mouse-2, or move there and type <RET>.
C-h a with a single word can find too many matches. Don't just give up; you can give Apropos a list of words to search for. When you specify more than one word in the apropos pattern, a name must contain at least two of the words in order to match. Thus, if you are looking for commands to kill a chunk of text before point, you could try C-h a kill back backward behind before <RET>.
For even greater flexibility, you can specify a regular expression (see Regexps). An apropos pattern is interpreted as a regular expression if it contains any of the regular expression special characters, ‘^$*+?.\[’.
Here is a set of arguments to give to C-h a that covers many classes of Emacs commands, since there are strong conventions for naming the standard Emacs commands. By giving you a feel for the naming conventions, this set should also serve to aid you in developing a technique for picking Apropos keywords.
char, line, word, sentence, paragraph, region, page, sexp, list, defun, rect, buffer, frame, window, face, file, dir, register, mode, beginning, end, forward, backward, next, previous, up, down, search, goto, kill, delete, mark, insert, yank, fill, indent, case, change, set, what, list, find, view, describe, default.
To list all Lisp symbols that contain a match for an Apropos pattern, not just the ones that are defined as commands, use the command M-x apropos instead of C-h a. This command does not check key bindings by default; specify a numeric argument if you want it to check them.
To list user-customizable variables that match an apropos pattern, use the command M-x apropos-variable. If you specify a prefix argument, it checks all variables.
The apropos-documentation command is like apropos
except that it searches documentation strings instead of symbol names
for matches for the specified Apropos pattern.
The apropos-value command is like apropos except that
it searches variables' values for matches for the pattern. With a
prefix argument, it also checks symbols' function definitions and
property lists.
If the variable apropos-do-all is non-nil, the commands
above all behave as if they had been given a prefix argument.
By default, Apropos lists the search results in alphabetical order.
If the variable apropos-sort-by-scores is non-nil,
Apropos tries to guess the relevance of each result, and displays the
most relevant ones first.
By default, Apropos lists the search results for
apropos-documentation in order of relevance of the match. If
the variable apropos-documentation-sort-by-scores is
nil, Apropos lists the symbols found in alphabetical order.
The C-h p command lets you search the standard Emacs Lisp libraries by topic keywords. Here is a partial list of keywords you can use:
| abbrev | abbreviation handling, typing shortcuts, macros.
|
| bib | code related to the bib bibliography processor.
|
| c | support for the C language and related languages.
|
| calendar | calendar and time management support.
|
| comm | communications, networking, remote access to files.
|
| convenience | convenience features for faster editing.
|
| data | support for editing files of data.
|
| docs | support for Emacs documentation.
|
| emulations | emulations of other editors.
|
| extensions | Emacs Lisp language extensions.
|
| faces | support for multiple fonts.
|
| files | support for editing and manipulating files.
|
| frames | support for Emacs frames and window systems.
|
| games | games, jokes and amusements.
|
| hardware | support for interfacing with exotic hardware.
|
| help | support for on-line help systems.
|
| hypermedia | support for links between text or other media types.
|
| i18n | internationalization and alternate character-set support.
|
| internal | code for Emacs internals, build process, defaults.
|
| languages | specialized modes for editing programming languages.
|
| lisp | Lisp support, including Emacs Lisp.
|
| local | code local to your site.
|
| maint | maintenance aids for the Emacs development group.
|
| modes for electronic-mail handling.
| |
| matching | various sorts of searching and matching.
|
| mouse | mouse support.
|
| multimedia | images and sound support.
|
| news | support for netnews reading and posting.
|
| oop | support for object-oriented programming.
|
| outlines | support for hierarchical outlining.
|
| processes | process, subshell, compilation, and job control support.
|
| terminals | support for terminal types.
|
| tex | supporting code for the TeX formatter.
|
| tools | programming tools.
|
| unix | front-ends/assistants for, or emulators of, UNIX-like features.
|
| wp | word processing.
|
You can use the command C-h L
(describe-language-environment) to find out information about
the support for a specific language environment. See Language Environments. This tells you which languages this language
environment is useful for, and lists the character sets, coding
systems, and input methods that go with it. It also shows some sample
text to illustrate scripts.
The command C-h h (view-hello-file) displays the file
etc/HELLO, which shows how to say “hello” in many languages.
The command C-h I (describe-input-method) describes
information about input methods—either a specified input method, or by
default the input method in use. See Input Methods.
The command C-h C (describe-coding-system) describes
information about coding systems—either a specified coding system, or
the ones currently in use. See Coding Systems.
Help buffers provide the same commands as View mode (see Misc File Ops), plus a few special commands of their own.
When a function name (see Running Commands by Name) or variable name (see Variables) appears in the documentation, it normally appears inside paired single-quotes. You can click on the name with Mouse-1 or Mouse-2, or move point there and type <RET>, to view the documentation of that command or variable. Use C-c C-b to retrace your steps.
You can follow cross references to URLs (web pages) as well. When
you follow a cross reference that is a URL, the browse-url
command is used to view the web page in a browser of your choosing.
See Browse-URL.
There are convenient commands for moving point to cross references in
the help text. <TAB> (help-next-ref) moves point down to the
next cross reference. Use S-<TAB> to move point up to the
previous cross reference (help-previous-ref).
C-h i (info) runs the Info program, which is used for
browsing through structured documentation files. The entire Emacs manual
is available within Info. Eventually all the documentation of the GNU
system will be available. Type h after entering Info to run
a tutorial on using Info.
With a numeric argument, C-h i selects an Info buffer with the number appended to the default ‘*info*’ buffer name (e.g. ‘*info*<2>’). This is useful if you want to browse multiple Info manuals simultaneously. If you specify just C-u as the prefix argument, C-h i prompts for the name of a documentation file. This way, you can browse a file which doesn't have an entry in the top-level Info menu. It is also handy when you need to get to the documentation quickly, and you know the exact name of the file.
There are two special help commands for accessing Emacs
documentation through Info. C-h F function <RET>
enters Info and goes straight to the documentation of the Emacs
function function. C-h K key enters Info and goes
straight to the documentation of the key key. These two keys
run the commands Info-goto-emacs-command-node and
Info-goto-emacs-key-command-node. You can use C-h K to
find the documentation of a menu item: just select that menu item when
C-h K prompts for a key.
C-h F and C-h K know about commands and keys described in manuals other than the Emacs manual. Thus, they make it easier to find the documentation of commands and keys when you are not sure which manual describes them, like when using some specialized mode.
When editing a program, if you have an Info version of the manual
for the programming language, you can use the command C-h S
(info-lookup-symbol) to refer to the manual documentation for a
symbol (keyword, function or variable). The details of how this
command works depend on the major mode.
If something surprising happens, and you are not sure what commands you
typed, use C-h l (view-lossage). C-h l displays the last
100 command characters you typed in. If you see commands that you don't
know, you can use C-h c to find out what they do.
To review messages that recently appeared in the echo area, use
C-h e (view-echo-area-messages). This displays the
buffer *Messages*, where those messages are kept.
Emacs has numerous major modes, each of which redefines a few keys and
makes a few other changes in how editing works. C-h m
(describe-mode) displays documentation on the current major mode,
which normally describes all the commands that are changed in this
mode.
C-h b (describe-bindings) and C-h s
(describe-syntax) present other information about the current
Emacs mode. C-h b displays a list of all the key bindings now in
effect, showing the local bindings defined by the current minor modes first,
then the local bindings defined by the current major mode, and finally
the global bindings (see Key Bindings). C-h s displays the
contents of the syntax table, with explanations of each character's
syntax (see Syntax).
You can get a similar list for a particular prefix key by typing C-h after the prefix key. (There are a few prefix keys for which this does not work—those that provide their own bindings for C-h. One of these is <ESC>, because <ESC> C-h is actually C-M-h, which marks a defun.)
The Emacs help commands described above display the state of data bases within Emacs. Emacs has a few other help commands that display pre-written help files. These commands all have the form C-h C-char; that is, C-h followed by a control character.
The other C-h options display various files containing useful information.
describe-copying).
These are the rules under which you can copy and redistribute Emacs.
describe-distribution).
view-emacs-problems).
view-emacs-FAQ).
view-emacs-news).
describe-project).
view-todo).
describe-no-warranty).
When a region of text is “active,” so that you can select it with the mouse or a key like RET, it often has associated help text. Areas of the mode line are examples. On most window systems, the help text is displayed as a “tooltip” (sometimes known as “balloon help”), when you move the mouse over the active text. See Tooltips. On some systems, it is shown in the echo area. On text-only terminals, Emacs may not be able to follow the mouse and hence will not show the help text on mouse-over.
You can also access text region help info using the keyboard. The
command C-h . (display-local-help) displays any help text
associated with the text at point, using the echo area. If you want
help text to be displayed automatically whenever it is available at
point, set the variable help-at-pt-display-when-idle to
t.
Many Emacs commands operate on an arbitrary contiguous part of the current buffer. To specify the text for such a command to operate on, you set the mark at one end of it, and move point to the other end. The text between point and the mark is called the region. Emacs highlights the region whenever there is one, if you enable Transient Mark mode (see Transient Mark).
Certain Emacs commands set the mark; other editing commands do not affect it, so the mark remains where you set it last. Each Emacs buffer has its own mark, and setting the mark in one buffer has no effect on other buffers' marks. When you return to a buffer that was current earlier, its mark is at the same place as before.
The ends of the region are always point and the mark. It doesn't matter which of them was put in its current place first, or which one comes earlier in the text—the region starts from point or the mark (whichever comes first), and ends at point or the mark (whichever comes last). Every time you move point, or set the mark in a new place, the region changes.
Many commands that insert text, such as C-y (yank) and
M-x insert-buffer, position point and the mark at opposite ends
of the inserted text, so that the region consists of the text just
inserted.
Aside from delimiting the region, the mark is also useful for remembering a spot that you may want to go back to. To make this feature more useful, each buffer remembers 16 previous locations of the mark in the mark ring.
Here are some commands for setting the mark:
set-mark-command).
exchange-point-and-mark).
mouse-save-then-kill).
For example, suppose you wish to convert part of the buffer to
upper case, using the C-x C-u (upcase-region) command,
which operates on the text in the region. You can first go to the
beginning of the text to be capitalized, type C-<SPC> to put
the mark there, move to the end, and then type C-x C-u. Or, you
can set the mark at the end of the text, move to the beginning, and then
type C-x C-u.
The most common way to set the mark is with the C-<SPC> command
(set-mark-command). This sets the mark where point is. Then you
can move point away, leaving the mark behind.
There are two ways to set the mark with the mouse. You can drag mouse button one across a range of text; that puts point where you release the mouse button, and sets the mark at the other end of that range. Or you can click mouse button three, which sets the mark at point (like C-<SPC>) and then moves point where you clicked (like Mouse-1). Both of these methods copy the region into the kill ring in addition to setting the mark; that gives behavior consistent with other window-driven applications, but if you don't want to modify the kill ring, you must use keyboard commands to set the mark. See Mouse Commands.
When Emacs was developed, terminals had only one cursor, so Emacs does not show where the mark is located–you have to remember. If you enable Transient Mark mode (see below), then the region is highlighted when it is active; you can tell mark is at the other end of the highlighted region. But this only applies when the mark is active.
The usual solution to this problem is to set the mark and then use
it soon, before you forget where it is. Alternatively, you can see
where the mark is with the command C-x C-x
(exchange-point-and-mark) which puts the mark where point was
and point where the mark was. The extent of the region is unchanged,
but the cursor and point are now at the previous position of the mark.
In Transient Mark mode, this command also reactivates the mark.
C-x C-x is also useful when you are satisfied with the position of point but want to move the other end of the region (where the mark is); do C-x C-x to put point at that end of the region, and then move it. Using C-x C-x a second time, if necessary, puts the mark at the new position with point back at its original position.
For more facilities that allow you to go to previously set marks, see Mark Ring.
There is no such character as C-<SPC> in ASCII;
when you type <SPC> while holding down <CTRL> on a text
terminal, what you get is the character C-@. This key is also
bound to set-mark-command–so unless you are unlucky enough to
have a text terminal where typing C-<SPC> does not produce
C-@, you might as well think of this character as
C-<SPC>.
On a terminal that supports colors, Emacs has the ability to highlight the current region. But normally it does not. Why not?
Once you have set the mark in a buffer, there is always a region in that buffer. This is because every command that sets the mark also activates it, and nothing ever deactivates it. Highlighting the region all the time would be a nuisance. So normally Emacs highlights the region only immediately after you have selected one with the mouse.
If you want region highlighting, you can use Transient Mark mode. This is a more rigid mode of operation in which the region always “lasts” only until you use it; you explicitly must set up a region for each command that uses one. In Transient Mark mode, most of the time there is no region; therefore, highlighting the region when it exists is useful and not annoying. When Transient Mark mode is enabled, Emacs always highlights the region whenever there is a region.
To enable Transient Mark mode, type M-x transient-mark-mode. This command toggles the mode; you can use the same command to turn the mode off again.
Here are the details of Transient Mark mode:
set-mark-command).
This makes the mark active and thus begins highlighting of the region.
As you move point, you will see the highlighted region grow and
shrink.
exchange-point-and-mark).
The highlighting of the region uses the region face; you can
customize the appearance of the highlighted region by changing this
face. See Face Customization.
When multiple windows show the same buffer, they can have different
regions, because they can have different values of point (though they
all share one common mark position). Ordinarily, only the selected
window highlights its region (see Windows). However, if the
variable highlight-nonselected-windows is non-nil, then
each window highlights its own region (provided that Transient Mark mode
is enabled and the mark in the window's buffer is active).
If the variable mark-even-if-inactive is non-nil in
Transient Mark mode, then commands can use the mark and the region
even when it is inactive. Region highlighting appears and disappears
just as it normally does in Transient Mark mode, but the mark doesn't
really go away when the highlighting disappears, so you can still use
region commands.
Transient Mark mode is also sometimes known as “Zmacs mode” because the Zmacs editor on the MIT Lisp Machine handled the mark in a similar way.
If you don't like Transient Mark mode in general, you might still want to use it once in a while. To do this, type C-<SPC> C-<SPC> or C-u C-x C-x. These commands set or activate the mark, and enable Transient Mark mode only until the mark is deactivated.
exchange-point-and-mark, with a prefix argument.)
One of the secondary features of Transient Mark mode is that certain commands operate only on the region, when there is an active region. If you don't use Transient Mark mode, the region once set never becomes inactive, so there is no way for these commands to make such a distinction. Enabling Transient Mark mode momentarily gives you a way to use these commands on the region.
Momentary use of Transient Mark mode is also a way to highlight the region for the time being.
Once you have a region and the mark is active, here are some of the ways you can operate on the region:
Most commands that operate on the text in the region have the word
region in their names.
Here are the commands for placing point and the mark around a textual object such as a word, list, paragraph or page.
mark-word). This command and
the following one do not move point.
mark-sexp).
mark-paragraph).
mark-defun).
mark-whole-buffer).
mark-page).
M-@ (mark-word) puts the mark at the end of the next
word, while C-M-@ (mark-sexp) puts it at the end of the
next balanced expression (see Expressions). These commands handle
arguments just like M-f and C-M-f. If you repeat these
commands, that extends the region. For example, you can type either
C-u 2 M-@ or M-@ M-@ to mark the next two words. This
command also extends the region when the mark is active in Transient
Mark mode, regardless of the last command.
Other commands set both point and mark, to delimit an object in the
buffer. For example, M-h (mark-paragraph) moves point to
the beginning of the paragraph that surrounds or follows point, and
puts the mark at the end of that paragraph (see Paragraphs). It
prepares the region so you can indent, case-convert, or kill a whole
paragraph. With prefix argument, if the argument's value is positive,
M-h marks that many paragraphs starting with the one surrounding
point. If the prefix argument is −n, M-h also
marks n paragraphs, running back form the one surrounding point.
In that last case, point moves forward to the end of that paragraph,
and the mark goes at the start of the region. Repeating the M-h
command extends the region, just as with M-@ and C-M-@.
C-M-h (mark-defun) similarly puts point before, and the
mark after, the current (or following) major top-level definition, or
defun (see Moving by Defuns). Repeating C-M-h also extends
the region.
C-x C-p (mark-page) puts point before the current page,
and mark at the end (see Pages). The mark goes after the
terminating page delimiter (to include it in the region), while point
goes after the preceding page delimiter (to exclude it). A numeric
argument specifies a later page (if positive) or an earlier page (if
negative) instead of the current page.
Finally, C-x h (mark-whole-buffer) sets up the entire
buffer as the region, by putting point at the beginning and the mark at
the end.
In Transient Mark mode, all of these commands activate the mark.
Aside from delimiting the region, the mark is also useful for
remembering a spot that you may want to go back to. To make this
feature more useful, each buffer remembers 16 previous locations of the
mark, in the mark ring. Commands that set the mark also push the
old mark onto this ring. To return to a marked location, use C-u
C-<SPC> (or C-u C-@); this is the command
set-mark-command given a numeric argument. It moves point to
where the mark was, and restores the mark from the ring of former
marks.
If you set set-mark-command-repeat-pop to non-nil,
then when you repeat the character C-<SPC> after typing
C-u C-<SPC>, each repetition moves point to a previous mark
position from the ring. The mark positions you move through in this
way are not lost; they go to the end of the ring.
Each buffer has its own mark ring. All editing commands use the current buffer's mark ring. In particular, C-u C-<SPC> always stays in the same buffer.
Many commands that can move long distances, such as M-<
(beginning-of-buffer), start by setting the mark and saving the
old mark on the mark ring. This is to make it easier for you to move
back later. Searches set the mark if they move point. However, in
Transient Mark mode, these commands do not set the mark when the mark
is already active. You can tell when a command sets the mark because
it displays ‘Mark set’ in the echo area.
If you want to move back to the same place over and over, the mark ring may not be convenient enough. If so, you can record the position in a register for later retrieval (see Saving Positions in Registers).
The variable mark-ring-max specifies the maximum number of
entries to keep in the mark ring. If that many entries exist and
another one is pushed, the earliest one in the list is discarded. Repeating
C-u C-<SPC> cycles through the positions currently in the
ring.
The variable mark-ring holds the mark ring itself, as a list of
marker objects, with the most recent first. This variable is local in
every buffer.
In addition to the ordinary mark ring that belongs to each buffer, Emacs has a single global mark ring. It records a sequence of buffers in which you have recently set the mark, so you can go back to those buffers.
Setting the mark always makes an entry on the current buffer's mark ring. If you have switched buffers since the previous mark setting, the new mark position makes an entry on the global mark ring also. The result is that the global mark ring records a sequence of buffers that you have been in, and, for each buffer, a place where you set the mark.
The command C-x C-<SPC> (pop-global-mark) jumps to
the buffer and position of the latest entry in the global ring. It also
rotates the ring, so that successive uses of C-x C-<SPC> take
you to earlier and earlier buffers.
Killing means erasing text and copying it into the kill ring, from which you can bring it back into the buffer by yanking it. (Some systems use the terms “cutting” and “pasting” for these operations.) This is the most common way of moving or copying text within Emacs. Killing and yanking is very safe because Emacs remembers several recent kills, not just the last one. It is versatile, because the many commands for killing syntactic units can also be used for moving those units. But there are other ways of copying text for special purposes.
Most commands which erase text from the buffer save it in the kill
ring. These commands are known as kill commands. The commands
that erase text but do not save it in the kill ring are known as
delete commands. The C-x u (undo) command
(see Undo) can undo both kill and delete commands; the importance
of the kill ring is that you can also yank the text in a different
place or places. Emacs has only one kill ring for all buffers, so you
can kill text in one buffer and yank it in another buffer.
The delete commands include C-d (delete-char) and
<DEL> (delete-backward-char), which delete only one
character at a time, and those commands that delete only spaces or
newlines. Commands that can erase significant amounts of nontrivial
data generally do a kill operation instead. The commands' names and
individual descriptions use the words ‘kill’ and ‘delete’ to
say which kind of operation they perform.
You cannot kill read-only text, since such text does not allow any
kind of modification. But some users like to use the kill commands to
copy read-only text into the kill ring, without actually changing it.
Therefore, the kill commands work specially in a read-only buffer:
they move over text, and copy it to the kill ring, without actually
deleting it from the buffer. Normally, kill commands beep and display
an error message when this happens. But if you set the variable
kill-read-only-ok to a non-nil value, they just print a
message in the echo area to explain why the text has not been erased.
Deletion means erasing text and not saving it in the kill ring. For the most part, the Emacs commands that delete text are those that erase just one character or only whitespace.
delete-char). If your keyboard has a
<Delete> function key (usually located in the edit keypad), Emacs
binds it to delete-char as well.
delete-backward-char). Some keyboards
refer to this key as a “backspace key” and label it with a left arrow.
delete-horizontal-space).
just-one-space).
delete-blank-lines).
delete-indentation).
The most basic delete commands are C-d (delete-char) and
<DEL> (delete-backward-char). C-d deletes the
character after point, the one the cursor is “on top of.” This
doesn't move point. <DEL> deletes the character before the cursor,
and moves point back. You can delete newlines like any other characters
in the buffer; deleting a newline joins two lines. Actually, C-d
and <DEL> aren't always delete commands; when given arguments, they
kill instead, since they can erase more than one character this way.
Every keyboard has a large key, labeled <DEL>, <BACKSPACE>, <BS> or <DELETE>, which is a short distance above the <RET> or <ENTER> key and is normally used for erasing what you have typed. Regardless of the actual name on the key, in Emacs it is equivalent to <DEL>—or it should be.
Many keyboards (including standard PC keyboards) have a <BACKSPACE> key a short ways above <RET> or <ENTER>, and a <DELETE> key elsewhere. In that case, the <BACKSPACE> key is <DEL>, and the <DELETE> key is equivalent to C-d—or it should be.
Why do we say “or it should be”? When Emacs starts up using a window system, it determines automatically which key or keys should be equivalent to <DEL>. As a result, <BACKSPACE> and/or <DELETE> keys normally do the right things. But in some unusual cases Emacs gets the wrong information from the system. If these keys don't do what they ought to do, you need to tell Emacs which key to use for <DEL>. See DEL Does Not Delete, for how to do this.
On most text-only terminals, Emacs cannot tell which keys the keyboard really has, so it follows a uniform plan which may or may not fit your keyboard. The uniform plan is that the ASCII <DEL> character deletes, and the ASCII <BS> (backspace) character asks for help (it is the same as C-h). If this is not right for your keyboard, such as if you find that the key which ought to delete backwards enters Help instead, see DEL Does Not Delete.
The other delete commands are those which delete only whitespace
characters: spaces, tabs and newlines. M-\
(delete-horizontal-space) deletes all the spaces and tab
characters before and after point. M-<SPC>
(just-one-space) does likewise but leaves a single space after
point, regardless of the number of spaces that existed previously (even
if there were none before). With a numeric argument n, it
leaves n spaces after point.
C-x C-o (delete-blank-lines) deletes all blank lines
after the current line. If the current line is blank, it deletes all
blank lines preceding the current line as well (leaving one blank line,
the current line). On a solitary blank line, it deletes that line.
M-^ (delete-indentation) joins the current line and the
previous line, by deleting a newline and all surrounding spaces, usually
leaving a single space. See M-^.
kill-line).
kill-whole-line)
The simplest kill command is C-k. If given at the beginning of a line, it kills all the text on the line, leaving it blank. When used on a blank line, it kills the whole line including its newline. To kill an entire non-blank line, go to the beginning and type C-k twice.
More generally, C-k kills from point up to the end of the line, unless it is at the end of a line. In that case it kills the newline following point, thus merging the next line into the current one. Spaces and tabs that you can't see at the end of the line are ignored when deciding which case applies, so if point appears to be at the end of the line, you can be sure C-k will kill the newline.
When C-k is given a positive argument, it kills that many lines and the newlines that follow them (however, text on the current line before point is not killed). With a negative argument −n, it kills n lines preceding the current line (together with the text on the current line before point). Thus, C-u - 2 C-k at the front of a line kills the two previous lines.
C-k with an argument of zero kills the text before point on the current line.
If the variable kill-whole-line is non-nil, C-k at
the very beginning of a line kills the entire line including the
following newline. This variable is normally nil.
C-S-backspace (kill-whole-line) will kill a whole line
including its newline regardless of the position of point within the
line. Note that many character terminals will prevent you from typing
the key sequence C-S-backspace.
kill-region).
kill-word). See Words.
backward-kill-word).
backward-kill-sentence).
See Sentences.
kill-sentence).
kill-sexp). See Expressions.
zap-to-char).
The most general kill command is C-w (kill-region),
which kills everything between point and the mark. With this command,
you can kill any contiguous sequence of characters, if you first set
the region around them.
A convenient way of killing is combined with searching: M-z
(zap-to-char) reads a character and kills from point up to (and
including) the next occurrence of that character in the buffer. A
numeric argument acts as a repeat count. A negative argument means to
search backward and kill text before point.
Other syntactic units can be killed: words, with M-<DEL> and M-d (see Words); balanced expressions, with C-M-k (see Expressions); and sentences, with C-x <DEL> and M-k (see Sentences).
On multi-window terminals, the most recent kill done in Emacs is also the primary selection, if it is more recent than any selection you made in another program. This means that the paste commands of other applications with separate windows copy the text that you killed in Emacs. In addition, Emacs yank commands treat other applications' selections as part of the kill ring, so you can yank them into Emacs.
Many window systems follow the convention that insertion while text is selected deletes the selected text. You can make Emacs behave this way by enabling Delete Selection mode, with M-x delete-selection-mode, or using Custom. Another effect of this mode is that <DEL>, C-d and some other keys, when a selection exists, will kill the whole selection. It also enables Transient Mark mode (see Transient Mark).
Yanking means reinserting text previously killed. This is what some systems call “pasting.” The usual way to move or copy text is to kill it and then yank it elsewhere one or more times. This is very safe because Emacs remembers many recent kills, not just the last one.
yank).
yank-pop).
kill-ring-save). Some systems call this “copying”.
append-next-kill).
On window systems, if there is a current selection in some other application, and you selected it more recently than you killed any text in Emacs, C-y copies the selection instead of text killed within Emacs.
All killed text is recorded in the kill ring, a list of blocks of text that have been killed. There is only one kill ring, shared by all buffers, so you can kill text in one buffer and yank it in another buffer. This is the usual way to move text from one file to another. (See Accumulating Text, for some other ways.)
The command C-y (yank) reinserts the text of the most recent
kill. It leaves the cursor at the end of the text. It sets the mark at
the beginning of the text. See Mark.
C-u C-y leaves the cursor in front of the text, and sets the mark after it. This happens only if the argument is specified with just a C-u, precisely. Any other sort of argument, including C-u and digits, specifies an earlier kill to yank (see Earlier Kills).
The yank commands discard certain text properties from the text that
is yanked, those that might lead to annoying results. For instance,
they discard text properties that respond to the mouse or specify key
bindings. The variable yank-excluded-properties specifies the
properties to discard. Yanking of register contents and rectangles
also discard these properties.
To copy a block of text, you can use M-w
(kill-ring-save), which copies the region into the kill ring
without removing it from the buffer. This is approximately equivalent
to C-w followed by C-x u, except that M-w does not
alter the undo history and does not temporarily change the screen.
Normally, each kill command pushes a new entry onto the kill ring. However, two or more kill commands in a row combine their text into a single entry, so that a single C-y yanks all the text as a unit, just as it was before it was killed.
Thus, if you want to yank text as a unit, you need not kill all of it with one command; you can keep killing line after line, or word after word, until you have killed it all, and you can still get it all back at once.
Commands that kill forward from point add onto the end of the previous killed text. Commands that kill backward from point add text onto the beginning. This way, any sequence of mixed forward and backward kill commands puts all the killed text into one entry without rearrangement. Numeric arguments do not break the sequence of appending kills. For example, suppose the buffer contains this text:
This is a line -!-of sample text.
with point shown by -!-. If you type M-d M-<DEL> M-d M-<DEL>, killing alternately forward and backward, you end up with ‘a line of sample’ as one entry in the kill ring, and ‘This is text.’ in the buffer. (Note the double space between ‘is’ and ‘text’, which you can clean up with M-<SPC> or M-q.)
Another way to kill the same text is to move back two words with M-b M-b, then kill all four words forward with C-u M-d. This produces exactly the same results in the buffer and in the kill ring. M-f M-f C-u M-<DEL> kills the same text, all going backward; once again, the result is the same. The text in the kill ring entry always has the same order that it had in the buffer before you killed it.
If a kill command is separated from the last kill command by other
commands (not just numeric arguments), it starts a new entry on the kill
ring. But you can force it to append by first typing the command
C-M-w (append-next-kill) right before it. The C-M-w
tells the following command, if it is a kill command, to append the text
it kills to the last killed text, instead of starting a new entry. With
C-M-w, you can kill several separated pieces of text and
accumulate them to be yanked back in one place.
A kill command following M-w does not append to the text that M-w copied into the kill ring.
To recover killed text that is no longer the most recent kill, use the
M-y command (yank-pop). It takes the text previously
yanked and replaces it with the text from an earlier kill. So, to
recover the text of the next-to-the-last kill, first use C-y to
yank the last kill, and then use M-y to replace it with the
previous kill. M-y is allowed only after a C-y or another
M-y.
You can understand M-y in terms of a “last yank” pointer which points at an entry in the kill ring. Each time you kill, the “last yank” pointer moves to the newly made entry at the front of the ring. C-y yanks the entry which the “last yank” pointer points to. M-y moves the “last yank” pointer to a different entry, and the text in the buffer changes to match. Enough M-y commands can move the pointer to any entry in the ring, so you can get any entry into the buffer. Eventually the pointer reaches the end of the ring; the next M-y loops back around to the first entry again.
M-y moves the “last yank” pointer around the ring, but it does not change the order of the entries in the ring, which always runs from the most recent kill at the front to the oldest one still remembered.
M-y can take a numeric argument, which tells it how many entries to advance the “last yank” pointer by. A negative argument moves the pointer toward the front of the ring; from the front of the ring, it moves “around” to the last entry and continues forward from there.
Once the text you are looking for is brought into the buffer, you can stop doing M-y commands and it will stay there. It's just a copy of the kill ring entry, so editing it in the buffer does not change what's in the ring. As long as no new killing is done, the “last yank” pointer remains at the same place in the kill ring, so repeating C-y will yank another copy of the same previous kill.
If you know how many M-y commands it would take to find the text you want, you can yank that text in one step using C-y with a numeric argument. C-y with an argument restores the text from the specified kill ring entry, counting back from the most recent as 1. Thus, C-u 2 C-y gets the next-to-the-last block of killed text—it is equivalent to C-y M-y. C-y with a numeric argument starts counting from the “last yank” pointer, and sets the “last yank” pointer to the entry that it yanks.
The length of the kill ring is controlled by the variable
kill-ring-max; no more than that many blocks of killed text are
saved.
The actual contents of the kill ring are stored in a variable named
kill-ring; you can view the entire contents of the kill ring with
the command C-h v kill-ring.
Usually we copy or move text by killing it and yanking it, but there are other convenient methods for copying one block of text in many places, or for copying many scattered blocks of text into one place. To copy one block to many places, store it in a register (see Registers). Here we describe the commands to accumulate scattered pieces of text into a buffer or into a file.
To accumulate text into a buffer, use M-x append-to-buffer.
This reads a buffer name, then inserts a copy of the region into the
buffer specified. If you specify a nonexistent buffer,
append-to-buffer creates the buffer. The text is inserted
wherever point is in that buffer. If you have been using the buffer for
editing, the copied text goes into the middle of the text of the buffer,
starting from wherever point happens to be at that moment.
Point in that buffer is left at the end of the copied text, so
successive uses of append-to-buffer accumulate the text in the
specified buffer in the same order as they were copied. Strictly
speaking, append-to-buffer does not always append to the text
already in the buffer—it appends only if point in that buffer is at the end.
However, if append-to-buffer is the only command you use to alter
a buffer, then point is always at the end.
M-x prepend-to-buffer is just like append-to-buffer
except that point in the other buffer is left before the copied text, so
successive prependings add text in reverse order. M-x
copy-to-buffer is similar, except that any existing text in the other
buffer is deleted, so the buffer is left containing just the text newly
copied into it.
To retrieve the accumulated text from another buffer, use the command M-x insert-buffer; this too takes buffername as an argument. It inserts a copy of the whole text in buffer buffername into the current buffer at point, and sets the mark after the inserted text. Alternatively, you can select the other buffer for editing, then copy text from it by killing. See Buffers, for background information on buffers.
Instead of accumulating text within Emacs, in a buffer, you can append text directly into a file with M-x append-to-file, which takes filename as an argument. It adds the text of the region to the end of the specified file. The file is changed immediately on disk.
You should use append-to-file only with files that are
not being visited in Emacs. Using it on a file that you are
editing in Emacs would change the file behind Emacs's back, which
can lead to losing some of your editing.
The rectangle commands operate on rectangular areas of the text: all the characters between a certain pair of columns, in a certain range of lines. Commands are provided to kill rectangles, yank killed rectangles, clear them out, fill them with blanks or text, or delete them. Rectangle commands are useful with text in multicolumn formats, and for changing text into or out of such formats.
When you must specify a rectangle for a command to work on, you do it by putting the mark at one corner and point at the opposite corner. The rectangle thus specified is called the region-rectangle because you control it in much the same way as the region is controlled. But remember that a given combination of point and mark values can be interpreted either as a region or as a rectangle, depending on the command that uses them.
If point and the mark are in the same column, the rectangle they delimit is empty. If they are in the same line, the rectangle is one line high. This asymmetry between lines and columns comes about because point (and likewise the mark) is between two columns, but within a line.
kill-rectangle).
delete-rectangle).
yank-rectangle).
open-rectangle). This pushes the previous contents of the
region-rectangle rightward.
clear-rectangle).
string-rectangle).
The rectangle operations fall into two classes: commands for deleting and inserting rectangles, and commands for blank rectangles.
There are two ways to get rid of the text in a rectangle: you can
discard the text (delete it) or save it as the “last killed”
rectangle. The commands for these two ways are C-x r d
(delete-rectangle) and C-x r k (kill-rectangle). In
either case, the portion of each line that falls inside the rectangle's
boundaries is deleted, causing any following text on the line to
move left into the gap.
Note that “killing” a rectangle is not killing in the usual sense; the rectangle is not stored in the kill ring, but in a special place that can only record the most recent rectangle killed. This is because yanking a rectangle is so different from yanking linear text that different yank commands have to be used and yank-popping is hard to make sense of.
To yank the last killed rectangle, type C-x r y
(yank-rectangle). Yanking a rectangle is the opposite of killing
one. Point specifies where to put the rectangle's upper left corner.
The rectangle's first line is inserted there, the rectangle's second
line is inserted at the same horizontal position, but one line
vertically down, and so on. The number of lines affected is determined
by the height of the saved rectangle.
You can convert single-column lists into double-column lists using rectangle killing and yanking; kill the second half of the list as a rectangle and then yank it beside the first line of the list. See Two-Column, for another way to edit multi-column text.
You can also copy rectangles into and out of registers with C-x r r r and C-x r i r. See Rectangle Registers.
There are two commands you can use for making blank rectangles:
C-x r c (clear-rectangle) which blanks out existing text,
and C-x r o (open-rectangle) which inserts a blank
rectangle. Clearing a rectangle is equivalent to deleting it and then
inserting a blank rectangle of the same size.
The command M-x delete-whitespace-rectangle deletes horizontal whitespace starting from a particular column. This applies to each of the lines in the rectangle, and the column is specified by the left edge of the rectangle. The right edge of the rectangle does not make any difference to this command.
The command C-x r t (string-rectangle) replaces the
contents of a region-rectangle with a string on each line. The
string's width need not be the same as the width of the rectangle. If
the string's width is less, the text after the rectangle shifts left;
if the string is wider than the rectangle, the text after the
rectangle shifts right.
The command M-x string-insert-rectangle is similar to
string-rectangle, but inserts the string on each line,
shifting the original text to the right.
The command M-x cua-mode sets up key bindings that are
compatible with the Common User Access (CUA) system used in many other
applications. C-x means cut (kill), C-c copy, C-v
paste (yank), and C-z undo. Standard Emacs commands like
C-x C-c still work, because C-x and C-c only take
effect when the mark is active (and the region is highlighted).
However, if you don't want these bindings at all, set
cua-enable-cua-keys to nil.
In CUA mode, using Shift together with the movement keys activates and highlights the region over which they move. The standard (unshifted) movement keys deactivate the mark, and typed text replaces the active region as in Delete-Selection mode (see Graphical Kill).
To run a command like C-x C-f while the mark is active, use one of the following methods: either hold Shift together with the prefix key, e.g. S-C-x C-f, or quickly type the prefix key twice, e.g. C-x C-x C-f.
CUA mode provides enhanced rectangle support with visible rectangle highlighting. Use C-RET to start a rectangle, extend it using the movement commands, and cut or copy it using C-x or C-c. RET moves the cursor to the next (clockwise) corner of the rectangle, so you can easily expand it in any direction. Normal text you type is inserted to the left or right of each line in the rectangle (on the same side as the cursor).
With CUA you can easily copy text and rectangles into and out of
registers by providing a one-digit numeric prefix the the kill, copy,
and yank commands, e.g. C-1 C-c copies the region into register
1, and C-2 C-v yanks the contents of register 2.
CUA mode also has a global mark feature which allows easy moving and copying of text between buffers. Use C-S-SPC to toggle the global mark on and off. When the global mark is on, all text that you kill or copy is automatically inserted at the global mark, and text you type is inserted at the global mark rather than at the current position.
For example, to copy words from various buffers into a word list in a given buffer, set the global mark in the target buffer, then navigate to each of the words you want in the list, mark it (e.g. with S-M-f), copy it to the list with C-c or M-w, and insert a newline after the word in the target list by pressing <RET>.
Emacs registers are compartments where you can save text, rectangles, positions, and other things for later use. Once you save text or a rectangle in a register, you can copy it into the buffer once, or many times; you can move point to a position saved in a register once, or many times.
Each register has a name, which consists of a single character. A register can store a number, a piece of text, a rectangle, a position, a window configuration, or a file name, but only one thing at any given time. Whatever you store in a register remains there until you store something else in that register. To see what a register r contains, use M-x view-register.
Saving a position records a place in a buffer so that you can move back there later. Moving to a saved position switches to that buffer and moves point to that place in it.
point-to-register).
jump-to-register).
To save the current position of point in a register, choose a name r and type C-x r <SPC> r. The register r retains the position thus saved until you store something else in that register.
The command C-x r j r moves point to the position recorded in register r. The register is not affected; it continues to hold the same position. You can jump to the saved position any number of times.
If you use C-x r j to go to a saved position, but the buffer it was saved from has been killed, C-x r j tries to create the buffer again by visiting the same file. Of course, this works only for buffers that were visiting files.
When you want to insert a copy of the same piece of text several times, it may be inconvenient to yank it from the kill ring, since each subsequent kill moves that entry further down the ring. An alternative is to store the text in a register and later retrieve it.
copy-to-register).
insert-register).
C-x r s r stores a copy of the text of the region into the register named r. C-u C-x r s r, the same command with a numeric argument, deletes the text from the buffer as well; you can think of this as “moving” the region text into the register.
M-x append-to-register <RET> r appends the copy of
the text in the region to the text already stored in the register
named r. If invoked with a numeric argument, it deletes the
region after appending it to the register. The command
prepend-to-register is similar, except that it prepends
the region text to the text in the register, rather than
appending it.
C-x r i r inserts in the buffer the text from register r. Normally it leaves point before the text and places the mark after, but with a numeric argument (C-u) it puts point after the text and the mark before.
A register can contain a rectangle instead of linear text. The rectangle is represented as a list of strings. See Rectangles, for basic information on how to specify a rectangle in the buffer.
copy-rectangle-to-register). With numeric argument, delete it as
well.
insert-register).
The C-x r i r command inserts a text string if the register contains one, and inserts a rectangle if the register contains one.
See also the command sort-columns, which you can think of
as sorting a rectangle. See Sorting.
You can save the window configuration of the selected frame in a register, or even the configuration of all windows in all frames, and restore the configuration later.
window-configuration-to-register).
frame-configuration-to-register).
Use C-x r j r to restore a window or frame configuration. This is the same command used to restore a cursor position. When you restore a frame configuration, any existing frames not included in the configuration become invisible. If you wish to delete these frames instead, use C-u C-x r j r.
There are commands to store a number in a register, to insert the number in the buffer in decimal, and to increment it. These commands can be useful in keyboard macros (see Keyboard Macros).
number-to-register).
increment-register).
C-x r i is the same command used to insert any other sort of register contents into the buffer. C-x r + with no numeric argument increments the register value by 1; C-x r n with no numeric argument stores zero in the register.
If you visit certain file names frequently, you can visit them more conveniently if you put their names in registers. Here's the Lisp code used to put a file name in a register:
(set-register ?r '(file . name))
For example,
(set-register ?z '(file . "/gd/gnu/emacs/19.0/src/ChangeLog"))
puts the file name shown in register ‘z’.
To visit the file whose name is in register r, type C-x r j r. (This is the same command used to jump to a position or restore a frame configuration.)
Bookmarks are somewhat like registers in that they record positions you can jump to. Unlike registers, they have long names, and they persist automatically from one Emacs session to the next. The prototypical use of bookmarks is to record “where you were reading” in various files.
bookmark-set).
bookmark-jump).
list-bookmarks).
The prototypical use for bookmarks is to record one current position in each of several files. So the command C-x r m, which sets a bookmark, uses the visited file name as the default for the bookmark name. If you name each bookmark after the file it points to, then you can conveniently revisit any of those files with C-x r b, and move to the position of the bookmark at the same time.
To display a list of all your bookmarks in a separate buffer, type
C-x r l (list-bookmarks). If you switch to that buffer,
you can use it to edit your bookmark definitions or annotate the
bookmarks. Type C-h m in the bookmark buffer for more
information about its special editing commands.
When you kill Emacs, Emacs offers to save your bookmark values in your default bookmark file, ~/.emacs.bmk, if you have changed any bookmark values. You can also save the bookmarks at any time with the M-x bookmark-save command. The bookmark commands load your default bookmark file automatically. This saving and loading is how bookmarks persist from one Emacs session to the next.
If you set the variable bookmark-save-flag to 1, then each
command that sets a bookmark will also save your bookmarks; this way,
you don't lose any bookmark values even if Emacs crashes. (The value,
if a number, says how many bookmark modifications should go by between
saving.)
Bookmark position values are saved with surrounding context, so that
bookmark-jump can find the proper position even if the file is
modified slightly. The variable bookmark-search-size says how
many characters of context to record on each side of the bookmark's
position.
Here are some additional commands for working with bookmarks:
bookmark-write, to
work with other files of bookmark values in addition to your default
bookmark file.
Since only part of a large buffer fits in the window, Emacs tries to show a part that is likely to be interesting. Display-control commands allow you to specify which part of the text you want to see, and how to display it.
You can specify various styles for displaying text using faces. Each face can specify various face attributes, such as the font family, the height, weight and slant of the characters, the foreground and background color, and underlining or overlining. A face does not have to specify all of these attributes; often it inherits most of them from another face.
On a window system, all the Emacs face attributes are meaningful. On a character terminal, only some of them work. Some character terminals support inverse video, bold, and underline attributes; some support colors. Character terminals generally do not support changing the height and width or the font family.
The easiest way to use faces is to turn on Font Lock mode.
See Font Lock, for more information about Font Lock mode and
syntactic highlighting. You can print out the buffer with the
highlighting that appears on your screen using the command
ps-print-buffer-with-faces. See PostScript.
Features which rely on text in multiple faces (such as Font Lock mode)
will also work on non-windowed terminals that can display more than one
face, whether by colors or underlining and emboldening. This includes
the console on GNU/Linux, an xterm which supports colors, the
MS-DOS display (see MS-DOS), and the MS-Windows version invoked with
the -nw option. Emacs determines automatically whether the
terminal has this capability.
You control the appearance of a part of the text in the buffer by
specifying the face or faces to use for it. The style of display used
for any given character is determined by combining the attributes of
all the applicable faces specified for that character. Any attribute
that isn't specified by these faces is taken from the default face,
whose attributes reflect the default settings of the frame itself.
Enriched mode, the mode for editing formatted text, includes several commands and menus for specifying faces for text in the buffer. See Format Faces, for how to specify the font for text in the buffer. See Format Colors, for how to specify the foreground and background color.
To alter the appearance of a face, use the customization buffer.
See Face Customization. You can also use X resources to specify
attributes of particular faces (see Resources). Alternatively,
you can change the foreground and background colors of a specific face
with M-x set-face-foreground and M-x set-face-background.
These commands prompt in the minibuffer for a face name and a color
name, with completion, and then set that face to use the specified
color. Changing the colors of the default face also changes
the foreground and background colors on all frames, both existing and
those to be created in the future. (You can also set foreground and
background colors for the current frame only; see Frame Parameters.)
Emacs can correctly display variable-width fonts, but Emacs commands that calculate width and indentation do not know how to calculate variable widths. This can sometimes lead to incorrect results when you use variable-width fonts. In particular, indentation commands can give inconsistent results, so we recommend you avoid variable-width fonts for editing program source code. Filling will sometimes make lines too long or too short. We plan to address these issues in future Emacs versions.
To see what faces are currently defined, and what they look like, type M-x list-faces-display. It's possible for a given face to look different in different frames; this command shows the appearance in the frame in which you type it.
Here are the standard faces for specifying text appearance. You can use them on specific text, when you want the effects they produce.
defaultbolditalicbold-italicunderlinefixed-pitchvariable-pitchshadowHere's an incomplete list of faces used to highlight parts of the text temporarily for specific purposes. (Many other modes define their own faces for this purpose.)
highlightmode-line-highlighthighlight, but used for portions of text on mode lines.
isearchlazy-highlightregionsecondary-selectiontrailing-whitespaceshow-trailing-whitespace is non-nil; see
Useless Whitespace.
nobreak-spaceescape-glyph When Transient Mark mode is enabled, the text of the region is
highlighted when the mark is active. This uses the face named
region; you can control the style of highlighting by changing the
style of this face (see Face Customization). See Transient Mark,
for more information about Transient Mark mode and activation and
deactivation of the mark.
These faces control the appearance of parts of the Emacs frame. They exist as faces to provide a consistent way to customize the appearance of these parts of the frame.
mode-linemodelinemodeline is an alias for the mode-line face, for
compatibility with old Emacs versions.
mode-line-inactivemode-line, but used for mode lines of the windows other
than the selected one (if mode-line-in-non-selected-windows is
non-nil). This face inherits from mode-line, so changes
in that face affect mode lines in all windows.
header-linemode-line for a window's header line. Most modes
don't use the header line, but some special modes, such the Info mode, do.
vertical-bordermode-line-inactive face
on character terminals. On window systems the foreground color of
this face is used for the vertical line between windows without
scrollbars.
minibuffer-promptminibuffer-prompt-properties, which is a list of text
properties used to display the prompt text.
fringescroll-barbordercursormousetool-bartooltipmenuFont Lock mode is a minor mode, always local to a particular buffer, which highlights (or “fontifies”) the buffer contents according to the syntax of the text you are editing. It can recognize comments and strings in most languages; in several languages, it can also recognize and properly highlight various other important constructs—for example, names of functions being defined or reserved keywords. Some special modes, such as Occur mode and Info mode, have completely specialized ways of assigning fonts for Font Lock mode.
Font Lock mode is turned on by default in all modes which support it. You can toggle font-lock for each buffer with the command M-x font-lock-mode. Using a positive argument unconditionally turns Font Lock mode on, and a negative or zero argument turns it off.
If you do not wish Font Lock mode to be turned on by default,
customize the variable global-font-lock-mode using the Customize
interface (see Easy Customization), or use the function
global-font-lock-mode in your .emacs file, like this:
(global-font-lock-mode 0)
If you have disabled Global Font Lock mode, you can still enable font
lock for specific major modes by adding the function
turn-on-font-lock to the mode hooks (see Hooks). For
example, to enable Font Lock mode for editing C files, you can do this:
(add-hook 'c-mode-hook 'turn-on-font-lock)
Font Lock mode uses several specifically named faces to do its job,
including font-lock-string-face, font-lock-comment-face,
and others. The easiest way to find them all is to use
M-x customize-group <RET> font-lock-faces <RET>.
To change the colors or the fonts used by Font Lock mode to fontify different parts of text, just change these faces. There are two ways to do it:
The variable font-lock-maximum-decoration specifies the
preferred level of fontification, for modes that provide multiple
levels. Level 1 is the least amount of fontification; some modes
support levels as high as 3. The normal default is “as high as
possible.” You can specify an integer, which applies to all modes, or
you can specify different numbers for particular major modes; for
example, to use level 1 for C/C++ modes, and the default level
otherwise, use this:
(setq font-lock-maximum-decoration
'((c-mode . 1) (c++-mode . 1)))
Fontification can be too slow for large buffers, so you can suppress
it. The variable font-lock-maximum-size specifies a buffer size,
beyond which buffer fontification is suppressed.
Comment and string fontification (or “syntactic” fontification) relies on analysis of the syntactic structure of the buffer text. For the sake of speed, some modes, including C mode and Lisp mode, rely on a special convention: an open-parenthesis or open-brace in the leftmost column always defines the beginning of a defun, and is thus always outside any string or comment. (See Left Margin Paren.) If you don't follow this convention, Font Lock mode can misfontify the text that follows an open-parenthesis or open-brace in the leftmost column that is inside a string or comment.
The variable font-lock-beginning-of-syntax-function (always
buffer-local) specifies how Font Lock mode can find a position
guaranteed to be outside any comment or string. In modes which use the
leftmost column parenthesis convention, the default value of the variable
is beginning-of-defun—that tells Font Lock mode to use the
convention. If you set this variable to nil, Font Lock no longer
relies on the convention. This avoids incorrect results, but the price
is that, in some cases, fontification for a changed text must rescan
buffer text from the beginning of the buffer. This can considerably
slow down redisplay while scrolling, particularly if you are close to
the end of a large buffer.
Font Lock highlighting patterns already exist for many modes, but you
may want to fontify additional patterns. You can use the function
font-lock-add-keywords, to add your own highlighting patterns for
a particular mode. For example, to highlight ‘FIXME:’ words in C
comments, use this:
(font-lock-add-keywords
'c-mode
'(("\\<\\(FIXME\\):" 1 font-lock-warning-face t)))
To remove keywords from the font-lock highlighting patterns, use the
function font-lock-remove-keywords. See Search-based Fontification, for
documentation of the format of this list.
Fontifying large buffers can take a long time. To avoid large delays when a file is visited, Emacs fontifies only the visible portion of a buffer. As you scroll through the buffer, each portion that becomes visible is fontified as soon as it is displayed. The parts of the buffer that are not displayed are fontified “stealthily,” in the background, i.e. when Emacs is idle. You can control this background fontification, also called Just-In-Time (or JIT) Lock, by customizing variables in the customization group ‘jit-lock’. See Specific Customization.
It is sometimes useful to temporarily highlight text that matches a certain regular expression. For example, you might wish to see all the references to a certain variable in a program source file, highlight certain parts in a voluminous output of some program, or make certain names stand out in an article.
Use the M-x hi-lock-mode command to turn on a minor mode that
allows you to interactively add and remove regular expressions
specifying text to be highlighted. Hi Lock mode works like Font Lock
mode (see Font Lock), except that it lets you easily add and
remove regular expressions while you are editing a buffer. To enable
Hi Lock mode for all buffers use M-x global-hi-lock-mode or
place (global-hi-lock-mode 1) in your .emacs file.
You control Hi Lock mode with these commands:
highlight-regexp). By using this command more than once, you
can highlight various parts of the text in different ways. The
highlighting will remain as long as the buffer is loaded. For
example, to highlight all occurrences of the word “whim” using the
default face (a yellow background) C-x w h whim <RET>
<RET>. Any face can be used for highlighting, Hi Lock provides
several of its own and these are pre-loaded into a history list. While
being prompted for a face use M-p and M-n to cycle through
them.
unhighlight-regexp).
When activated from the menu select the expression to unhighlight from
a list. When activated from the keyboard the most recently added
expression will be shown. Use M-p to show the next older
expression and M-n to select the next newer expression. When
the expression to unhighlight appears press <RET> to unhighlight
it. The expression can also be typed and completion is available.
highlight-lines-matching-regexp).
hi-lock-write-interactive-patterns command.
These patterns will be read the next time you visit the file while
Hi Lock mode is enabled, or whenever you use the M-x
hi-lock-find-patterns command.
hi-lock-write-interactive-patterns). Users familiar with Font
Lock keywords might interactively enter patterns
(highlight-regexp), write them into the file
(hi-lock-write-interactive-patterns), edit them, perhaps
including different faces for different parenthesized parts of the
match, and finally use this command
(hi-lock-write-interactive-patterns) to have Hi Lock highlight
them.
This command does nothing if the major mode is a member of the list
hi-lock-exclude-modes.
Use M-x highlight-changes-mode to enable a minor mode that uses faces (colors, typically) to indicate which parts of the buffer were changed most recently.
If a buffer contains text that is too large to fit entirely within a window that is displaying the buffer, Emacs shows a contiguous portion of the text. The portion shown always contains point.
Scrolling means moving text up or down in the window so that different parts of the text are visible. Scrolling forward means that text moves up, and new text appears at the bottom. Scrolling backward moves text down and new text appears at the top.
Scrolling happens automatically if you move point past the bottom or top of the window. You can also explicitly request scrolling with the commands in this section.
recenter).
scroll-up).
scroll-down).
recenter).
reposition-window).
The most basic scrolling command is C-l (recenter) with
no argument. It scrolls the selected window so that point is halfway
down from the top of the window. On a text terminal, it also clears
the screen and redisplays all windows. That is useful in case the
screen is garbled (see Screen Garbled).
To read the buffer a windowful at a time, use C-v
(scroll-up) with no argument. This scrolls forward by nearly
the whole window height. The effect is to take the two lines at the
bottom of the window and put them at the top, followed by nearly a
whole windowful of lines that were not previously visible. If point
was in the text that scrolled off the top, it ends up at the new top
of the window.
M-v (scroll-down) with no argument scrolls backward in
a similar way, also with overlap. The number of lines of overlap
across a C-v or M-v is controlled by the variable
next-screen-context-lines; by default, it is 2. The function
keys <NEXT> and <PRIOR>, or <PAGEDOWN> and <PAGEUP>,
are equivalent to C-v and M-v.
The commands C-v and M-v with a numeric argument scroll the text in the selected window up or down a few lines. C-v with an argument moves the text and point up, together, that many lines; it brings the same number of new lines into view at the bottom of the window. M-v with numeric argument scrolls the text downward, bringing that many new lines into view at the top of the window. C-v with a negative argument is like M-v and vice versa.
The names of scroll commands are based on the direction that the
text moves in the window. Thus, the command to scroll forward is
called scroll-up because it moves the text upward on the
screen. The keys <PAGEDOWN> and <PAGEUP> derive their names
and customary meanings from a different convention that developed
elsewhere; hence the strange result that <PAGEDOWN> runs
scroll-up.
Some users like the full-screen scroll commands to keep point at the
same screen line. To enable this behavior, set the variable
scroll-preserve-screen-position to a non-nil value. In
this mode, when scrolling shifts point off the screen, or into the
scrolling margins, Emacs moves point to keep the same vertical
position within the window. This mode is convenient for browsing
through a file by scrolling by screenfuls; if you come back to the
screen where you started, point goes back to the line where it
started. However, this mode is inconvenient when you move to the next
screen in order to move point to the text there.
Another way to do scrolling is with C-l with a numeric argument. C-l does not clear the screen when given an argument; it only scrolls the selected window. With a positive argument n, it repositions text to put point n lines down from the top. An argument of zero puts point on the very top line. Point does not move with respect to the text; rather, the text and point move rigidly on the screen. C-l with a negative argument puts point that many lines from the bottom of the window. For example, C-u - 1 C-l puts point on the bottom line, and C-u - 5 C-l puts it five lines from the bottom. C-u C-l scrolls to put point at the center (vertically) of the selected window.
The C-M-l command (reposition-window) scrolls the current
window heuristically in a way designed to get useful information onto
the screen. For example, in a Lisp file, this command tries to get the
entire current defun onto the screen if possible.
Scrolling happens automatically when point moves out of the visible
portion of the text. Normally, automatic scrolling centers point
vertically within the window. However, if you set
scroll-conservatively to a small number n, then if you
move point just a little off the screen—less than n
lines—then Emacs scrolls the text just far enough to bring point
back on screen. By default, scroll-conservatively is 0.
When the window does scroll by a longer distance, you can control
how aggressively it scrolls, by setting the variables
scroll-up-aggressively and scroll-down-aggressively.
The value of scroll-up-aggressively should be either
nil, or a fraction f between 0 and 1. A fraction
specifies where on the screen to put point when scrolling upward.
More precisely, when a window scrolls up because point is above the
window start, the new start position is chosen to put point f
part of the window height from the top. The larger f, the more
aggressive the scrolling.
nil, which is the default, scrolls to put point at the center.
So it is equivalent to .5.
Likewise, scroll-down-aggressively is used for scrolling
down. The value, f, specifies how far point should be placed
from the bottom of the window; thus, as with
scroll-up-aggressively, a larger value is more aggressive.
The variable scroll-margin restricts how close point can come
to the top or bottom of a window. Its value is a number of screen
lines; if point comes within that many lines of the top or bottom of the
window, Emacs recenters the window. By default, scroll-margin is
0.
Horizontal scrolling means shifting all the lines sideways within a window—so that some of the text near the left margin is not displayed at all. When the text in a window is scrolled horizontally, text lines are truncated rather than continued (see Display Custom). Whenever a window shows truncated lines, Emacs automatically updates its horizontal scrolling whenever point moves off the left or right edge of the screen. You can also use these commands to do explicit horizontal scrolling.
scroll-left).
scroll-right).
The command C-x < (scroll-left) scrolls the selected
window to the left by n columns with argument n. This moves
part of the beginning of each line off the left edge of the window.
With no argument, it scrolls by almost the full width of the window (two
columns less, to be precise).
C-x > (scroll-right) scrolls similarly to the right. The
window cannot be scrolled any farther to the right once it is displayed
normally (with each line starting at the window's left margin);
attempting to do so has no effect. This means that you don't have to
calculate the argument precisely for C-x >; any sufficiently large
argument will restore the normal display.
If you use those commands to scroll a window horizontally, that sets
a lower bound for automatic horizontal scrolling. Automatic scrolling
will continue to scroll the window, but never farther to the right
than the amount you previously set by scroll-left.
The value of the variable hscroll-margin controls how close
to the window's edges point is allowed to get before the window will
be automatically scrolled. It is measured in columns. If the value
is 5, then moving point within 5 columns of the edge causes horizontal
scrolling away from that edge.
The variable hscroll-step determines how many columns to
scroll the window when point gets too close to the edge. If it's
zero, horizontal scrolling centers point horizontally within the
window. If it's a positive integer, it specifies the number of
columns to scroll by. If it's a floating-point number, it specifies
the fraction of the window's width to scroll by. The default is zero.
To disable automatic horizontal scrolling, set the variable
auto-hscroll-mode to nil.
On a graphical display, each Emacs window normally has narrow fringes on the left and right edges. The fringes display indications about the text in the window.
The most common use of the fringes is to indicate a continuation line, when one line of text is split into multiple lines on the screen. The left fringe shows a curving arrow for each screen line except the first, indicating that “this is not the real beginning.” The right fringe shows a curving arrow for each screen line except the last, indicating that “this is not the real end.”
The fringes indicate line truncation with short horizontal arrows meaning “there's more text on this line which is scrolled horizontally out of view;” clicking the mouse on one of the arrows scrolls the display horizontally in the direction of the arrow. The fringes can also indicate other things, such as empty lines, or where a program you are debugging is executing (see Debuggers).
You can enable and disable the fringes for all frames using M-x fringe-mode. To enable and disable the fringes for the selected frame, use M-x set-fringe-style.
It is easy to leave unnecessary spaces at the end of a line, or empty lines at the end of a file, without realizing it. In most cases, this trailing whitespace has no effect, but there are special circumstances where it matters.
You can make trailing whitespace at the end of a line visible on the
screen by setting the buffer-local variable
show-trailing-whitespace to t. Then Emacs displays
trailing whitespace in the face trailing-whitespace.
This feature does not apply when point is at the end of the line containing the whitespace. Strictly speaking, that is “trailing whitespace” nonetheless, but displaying it specially in that case looks ugly while you are typing in new text. In this special case, the location of point is enough to show you that the spaces are present.
To delete all trailing whitespace within the current buffer's accessible portion (see Narrowing), type M-x delete-trailing-whitespace <RET>. (This command does not remove the form-feed characters.)
Emacs can indicate unused lines at the end of the window with a small image in the left fringe (see Fringes). The image appears for window lines that do not correspond to any buffer text. Blank lines at the end of the buffer then stand out because they do not have this image in the fringe.
To enable this feature, set the buffer-local variable
indicate-empty-lines to a non-nil value. The default
value of this variable is controlled by the variable
default-indicate-empty-lines; by setting that variable, you
can enable or disable this feature for all new buffers. (This feature
currently doesn't work on character terminals.)
Follow mode is a minor mode that makes two windows, both showing the same buffer, scroll as a single tall “virtual window.” To use Follow mode, go to a frame with just one window, split it into two side-by-side windows using C-x 3, and then type M-x follow-mode. From then on, you can edit the buffer in either of the two windows, or scroll either one; the other window follows it.
In Follow mode, if you move point outside the portion visible in one window and into the portion visible in the other window, that selects the other window—again, treating the two as if they were parts of one large window.
To turn off Follow mode, type M-x follow-mode a second time.
Emacs has the ability to hide lines indented more than a certain number of columns (you specify how many columns). You can use this to get an overview of a part of a program.
To hide lines in the current buffer, type C-x $
(set-selective-display) with a numeric argument n. Then
lines with at least n columns of indentation disappear from the
screen. The only indication of their presence is that three dots
(‘...’) appear at the end of each visible line that is
followed by one or more hidden ones.
The commands C-n and C-p move across the hidden lines as if they were not there.
The hidden lines are still present in the buffer, and most editing commands see them as usual, so you may find point in the middle of the hidden text. When this happens, the cursor appears at the end of the previous line, after the three dots. If point is at the end of the visible line, before the newline that ends it, the cursor appears before the three dots.
To make all lines visible again, type C-x $ with no argument.
If you set the variable selective-display-ellipses to
nil, the three dots do not appear at the end of a line that
precedes hidden lines. Then there is no visible indication of the
hidden lines. This variable becomes local automatically when set.
See also Outline Mode for another way to hide part of the text in a buffer.
The buffer percentage pos indicates the percentage of the buffer above the top of the window. You can additionally display the size of the buffer by typing M-x size-indication-mode to turn on Size Indication mode. The size will be displayed immediately following the buffer percentage like this:
POS of SIZE
Here SIZE is the human readable representation of the number of characters in the buffer, which means that ‘k’ for 10^3, ‘M’ for 10^6, ‘G’ for 10^9, etc., are used to abbreviate.
If you have narrowed the buffer (see Narrowing), the size of the accessible part of the buffer is shown.
The current line number of point appears in the mode line when Line Number mode is enabled. Use the command M-x line-number-mode to turn this mode on and off; normally it is on. The line number appears after the buffer percentage pos, with the letter ‘L’ to indicate what it is. See Minor Modes, for more information about minor modes and about how to use this command.
If you have narrowed the buffer (see Narrowing), the displayed line number is relative to the accessible portion of the buffer.
If the buffer is very large (larger than the value of
line-number-display-limit), then the line number doesn't appear.
Emacs doesn't compute the line number when the buffer is large, because
that would be too slow. Set it to nil to remove the limit.
Line-number computation can also be slow if the lines in the buffer
are too long. For this reason, Emacs normally doesn't display line
numbers if the average width, in characters, of lines near point is
larger than the value of the variable
line-number-display-limit-width. The default value is 200
characters.
You can also display the current column number by turning on Column Number mode. It displays the current column number preceded by the letter ‘C’. Type M-x column-number-mode to toggle this mode.
Emacs can optionally display the time and system load in all mode
lines. To enable this feature, type M-x display-time or customize
the option display-time-mode. The information added to the mode
line usually appears after the buffer name, before the mode names and
their parentheses. It looks like this:
hh:mmpm l.ll
Here hh and mm are the hour and minute, followed always by
‘am’ or ‘pm’. l.ll is the average number of running
processes in the whole system recently. (Some fields may be missing if
your operating system cannot support them.) If you prefer time display
in 24-hour format, set the variable display-time-24hr-format
to t.
The word ‘Mail’ appears after the load level if there is mail
for you that you have not read yet. On a graphical display you can use
an icon instead of ‘Mail’ by customizing
display-time-use-mail-icon; this may save some space on the mode
line. You can customize display-time-mail-face to make the mail
indicator prominent. Use display-time-mail-file to specify
the mail file to check, or set display-time-mail-directory
to specify the directory to check for incoming mail (any nonempty regular
file in the directory is considered as “newly arrived mail”).
By default, the mode line is drawn on graphics displays with
3D-style highlighting, like that of a button when it is not being
pressed. If you don't like this effect, you can disable the 3D
highlighting of the mode line, by customizing the attributes of the
mode-line face in your .emacs init file, like this:
(set-face-attribute 'mode-line nil :box nil)
Alternatively, you can turn off the box attribute in your .Xdefaults file:
Emacs.mode-line.AttributeBox: off
By default, the mode line of nonselected windows is displayed in a
different face, called mode-line-inactive. Only the selected
window is displayed in the mode-line face. This helps show
which window is selected. When the minibuffer is selected, since
it has no mode line, the window from which you activated the minibuffer
has its mode line displayed using mode-line; as a result,
ordinary entry to the minibuffer does not change any mode lines.
You can disable use of mode-line-inactive by setting variable
mode-line-in-non-selected-windows to nil; then all mode
lines are displayed in the mode-line face.
ASCII printing characters (octal codes 040 through 0176) in Emacs buffers are displayed with their graphics, as are non-ASCII multibyte printing characters (octal codes above 0400).
Some ASCII control characters are displayed in special ways. The newline character (octal code 012) is displayed by starting a new line. The tab character (octal code 011) is displayed by moving to the next tab stop column (normally every 8 columns).
Other ASCII control characters are normally displayed as a caret (‘^’) followed by the non-control version of the character; thus, control-A is displayed as ‘^A’.
Non-ASCII characters 0200 through 0237 (octal) are displayed with octal escape sequences; thus, character code 0230 (octal) is displayed as ‘\230’. The display of character codes 0240 through 0377 (octal) may be either as escape sequences or as graphics. They do not normally occur in multibyte buffers, but if they do, they are displayed as Latin-1 graphics. In unibyte mode, if you enable European display they are displayed using their graphics (assuming your terminal supports them), otherwise as escape sequences. See Single-Byte Character Support.
Some character sets define “no-break” versions of the space and
hyphen characters, which are used where a line should not be broken.
Emacs normally displays these characters with special faces
(respectively, nobreak-space and escape-glyph) to
distinguish them from ordinary spaces and hyphens. You can turn off
this feature by setting the variable nobreak-char-display to
nil. If you set the variable to any other value, that means to
prefix these characters with an escape character.
You can customize the cursor's color, and whether it blinks, using
the cursor Custom group (see Easy Customization). On
graphical terminals, the command M-x blink-cursor-mode enables
or disables the blinking of the cursor. (On text terminals, the
terminal itself blinks the cursor, and Emacs has no control over it.)
You can control how the cursor appears when it blinks off by setting
the variable blink-cursor-alist.
Normally, the cursor appears in non-selected windows in the “off”
state, with the same appearance as when the blinking cursor blinks
“off”. For a box cursor, this is a hollow box; for a bar cursor,
this is a thinner bar. To turn off cursors in non-selected windows,
customize the variable cursor-in-non-selected-windows and assign
it a nil value.
On graphical terminals, Emacs can optionally draw the block cursor
as wide as the character under the cursor—for example, if the cursor
is on a tab character, it would cover the full width occupied by that
tab character. To enable this feature, set the variable
x-stretch-cursor to a non-nil value.
If you find it hard to see the cursor, you might like HL Line mode, a minor mode that highlights the line containing point. Use M-x hl-line-mode to enable or disable it in the current buffer. M-x global-hl-line-mode enables or disables the same mode globally.
This section contains information for customization only. Beginning users should skip it.
If the variable inverse-video is non-nil, Emacs attempts
to invert all the lines of the display from what they normally are.
If the variable visible-bell is non-nil, Emacs attempts
to make the whole screen blink when it would normally make an audible bell
sound. This variable has no effect if your terminal does not have a way
to make the screen blink.
On a text terminal, when you reenter Emacs after suspending, Emacs
normally clears the screen and redraws the entire display. On some
terminals with more than one page of memory, it is possible to arrange
the termcap entry so that the ‘ti’ and ‘te’ strings (output
to the terminal when Emacs is entered and exited, respectively) switch
between pages of memory so as to use one page for Emacs and another
page for other output. Then you might want to set the variable
no-redraw-on-reenter non-nil; this tells Emacs to
assume, when resumed, that the screen page it is using still contains
what Emacs last wrote there.
The variable echo-keystrokes controls the echoing of multi-character
keys; its value is the number of seconds of pause required to cause echoing
to start, or zero meaning don't echo at all. See Echo Area.
If the variable ctl-arrow is nil, all control characters in
the buffer are displayed with octal escape sequences, except for newline
and tab. Altering the value of ctl-arrow makes it local to the
current buffer; until that time, the default value is in effect. The
default is initially t. See Display Tables.
Normally, a tab character in the buffer is displayed as whitespace which
extends to the next display tab stop position, and display tab stops come
at intervals equal to eight spaces. The number of spaces per tab is
controlled by the variable tab-width, which is made local by
changing it, just like ctl-arrow. Note that how the tab character
in the buffer is displayed has nothing to do with the definition of
<TAB> as a command. The variable tab-width must have an
integer value between 1 and 1000, inclusive. The variable
default-tab-width controls the default value of this variable
for buffers where you have not set it locally.
As an alternative to continuation, Emacs can display long lines by truncation. This means that all the characters that do not fit in the width of the screen or window do not appear at all. On graphical terminals, a small straight arrow in the fringe indicates truncation at either end of the line. On text terminals, ‘$’ appears in the first column when there is text truncated to the left, and in the last column when there is text truncated to the right.
Horizontal scrolling automatically causes line truncation
(see Horizontal Scrolling). You can explicitly enable line
truncation for a particular buffer with the command M-x
toggle-truncate-lines. This works by locally changing the variable
truncate-lines. If that variable is non-nil, long lines
are truncated; if it is nil, they are continued onto multiple
screen lines. Setting the variable truncate-lines in any way
makes it local to the current buffer; until that time, the default
value is in effect. The default value is normally nil.
If the variable truncate-partial-width-windows is
non-nil, it forces truncation rather than continuation in any
window less than the full width of the screen or frame, regardless of
the value of truncate-lines. For information about side-by-side
windows, see Split Window. See also Display.
If the variable overflow-newline-into-fringe is
non-nil on a window system, it specifies that lines which are
exactly as wide as the window (not counting the final newline
character) shall not be broken into two lines on the display (with
just the newline on the second line). Instead, the newline
overflows into the right fringe, and the cursor will be displayed in
the fringe when positioned on that newline.
On a window system, Emacs may indicate the buffer boundaries in the fringes. The buffer boundaries, i.e. first and last line in the buffer, can be marked with angle bitmaps in the left or right fringe. This can be combined with up and down arrow bitmaps shown at the top and bottom of the left or right fringe if the window can be scrolled in either direction.
The buffer-local variable indicate-buffer-boundaries controls
how the buffer boundaries and window scrolling is indicated in the
fringes.
If the value is left or right, both angle and arrow
bitmaps are displayed in the left or right fringe, respectively.
If value is an alist, each element (indicator .
position) specifies the position of one of the indicators.
The indicator must be one of top, bottom,
up, down, or t which specifies the default
position for the indicators not present in the alist.
The position is one of left, right, or nil
which specifies not to show this indicator.
For example, ((top . left) (t . right)) places the top angle
bitmap in left fringe, the bottom angle bitmap in right fringe, and
both arrow bitmaps in right fringe. To show just the angle bitmaps in
the left fringe, but no arrow bitmaps, use ((top . left)
(bottom . left)).
The value of the variable default-indicate-buffer-boundaries
is the default value for indicate-buffer-boundaries in buffers
that do not override it.
The variable baud-rate holds the output speed of the
terminal, as far as Emacs knows. Setting this variable does not
change the speed of actual data transmission, but the value is used
for calculations. On terminals, it affects padding, and decisions
about whether to scroll part of the screen or redraw it instead.
It also affects the behavior of incremental search.
On window-systems, baud-rate is only used to determine how
frequently to look for pending input during display updating. A
higher value of baud-rate means that check for pending input
will be done less frequently.
You can customize the way any particular character code is displayed by means of a display table. See Display Tables.
On a window system, Emacs can optionally display the mouse pointer
in a special shape to say that Emacs is busy. To turn this feature on
or off, customize the group cursor. You can also control the
amount of time Emacs must remain busy before the busy indicator is
displayed, by setting the variable hourglass-delay.
On some text-only terminals, bold face and inverse video together
result in text that is hard to read. Call the function
tty-suppress-bold-inverse-default-colors with a non-nil
argument to suppress the effect of bold-face in this case.
Like other editors, Emacs has commands for searching for occurrences of a string. The principal search command is unusual in that it is incremental; it begins to search before you have finished typing the search string. There are also nonincremental search commands more like those of other editors.
Besides the usual replace-string command that finds all
occurrences of one string and replaces them with another, Emacs has a
more flexible replacement command called query-replace, which
asks interactively which occurrences to replace.
An incremental search begins searching as soon as you type the first character of the search string. As you type in the search string, Emacs shows you where the string (as you have typed it so far) would be found. When you have typed enough characters to identify the place you want, you can stop. Depending on what you plan to do next, you may or may not need to terminate the search explicitly with <RET>.
isearch-forward).
isearch-backward).
C-s starts a forward incremental search. It reads characters from the keyboard, and moves point past the next occurrence of those characters. If you type C-s and then F, that puts the cursor after the first ‘F’ (the first following the starting point, since this is a forward search). Then if you type an O, you will see the cursor move just after the first ‘FO’ (the ‘F’ in that ‘FO’ may or may not be the first ‘F’). After another O, the cursor moves after the first ‘FOO’ after the place where you started the search. At each step, the buffer text that matches the search string is highlighted, if the terminal can do that; the current search string is always displayed in the echo area.
If you make a mistake in typing the search string, you can cancel characters with <DEL>. Each <DEL> cancels the last character of search string. This does not happen until Emacs is ready to read another input character; first it must either find, or fail to find, the character you want to erase. If you do not want to wait for this to happen, use C-g as described below.
When you are satisfied with the place you have reached, you can type <RET>, which stops searching, leaving the cursor where the search brought it. Also, any command not specially meaningful in searches stops the searching and is then executed. Thus, typing C-a would exit the search and then move to the beginning of the line. <RET> is necessary only if the next command you want to type is a printing character, <DEL>, <RET>, or another character that is special within searches (C-q, C-w, C-r, C-s, C-y, M-y, M-r, M-c, M-e, and some other meta-characters).
When you exit the incremental search, it sets the mark where point was before the search. That is convenient for moving back there. In Transient Mark mode, incremental search sets the mark without activating it, and does so only if the mark is not already active.
Sometimes you search for ‘FOO’ and find one, but not the one you expected to find. There was a second ‘FOO’ that you forgot about, before the one you were aiming for. In this event, type another C-s to move to the next occurrence of the search string. You can repeat this any number of times. If you overshoot, you can cancel some C-s characters with <DEL>.
After you exit a search, you can search for the same string again by typing just C-s C-s: the first C-s is the key that invokes incremental search, and the second C-s means “search again.”
If a search is failing and you ask to repeat it by typing another C-s, it starts again from the beginning of the buffer. Repeating a failing reverse search with C-r starts again from the end. This is called wrapping around, and ‘Wrapped’ appears in the search prompt once this has happened. If you keep on going past the original starting point of the search, it changes to ‘Overwrapped’, which means that you are revisiting matches that you have already seen.
To reuse earlier search strings, use the search ring. The commands M-p and M-n move through the ring to pick a search string to reuse. These commands leave the selected search ring element in the minibuffer, where you can edit it. To edit the current search string in the minibuffer without replacing it with items from the search ring, type M-e. Type C-s or C-r to terminate editing the string and search for it.
You can change to searching backwards with C-r. If a search fails because the place you started was too late in the file, you should do this. Repeated C-r keeps looking for more occurrences backwards. A C-s starts going forwards again. C-r in a search can be canceled with <DEL>.
If you know initially that you want to search backwards, you can use
C-r instead of C-s to start the search, because C-r as
a key runs a command (isearch-backward) to search backward. A
backward search finds matches that are entirely before the starting
point, just as a forward search finds matches that begin after it.
If your string is not found at all, the echo area says ‘Failing I-Search’. The cursor is after the place where Emacs found as much of your string as it could. Thus, if you search for ‘FOOT’, and there is no ‘FOOT’, you might see the cursor after the ‘FOO’ in ‘FOOL’. At this point there are several things you can do. If your string was mistyped, you can rub some of it out and correct it. If you like the place you have found, you can type <RET> or some other Emacs command to remain there. Or you can type C-g, which removes from the search string the characters that could not be found (the ‘T’ in ‘FOOT’), leaving those that were found (the ‘FOO’ in ‘FOOT’). A second C-g at that point cancels the search entirely, returning point to where it was when the search started.
The C-g “quit” character does special things during searches; just what it does depends on the status of the search. If the search has found what you specified and is waiting for input, C-g cancels the entire search. The cursor moves back to where you started the search. If C-g is typed when there are characters in the search string that have not been found—because Emacs is still searching for them, or because it has failed to find them—then the search string characters which have not been found are discarded from the search string. With them gone, the search is now successful and waiting for more input, so a second C-g will cancel the entire search.
An upper-case letter in the search string makes the search case-sensitive. If you delete the upper-case character from the search string, it ceases to have this effect. See Search Case.
To search for a newline, type C-j. To search for another control character, such as control-S or carriage return, you must quote it by typing C-q first. This function of C-q is analogous to its use for insertion (see Inserting Text): it causes the following character to be treated the way any “ordinary” character is treated in the same context. You can also specify a character by its octal code: enter C-q followed by a sequence of octal digits.
M-% typed in incremental search invokes query-replace
or query-replace-regexp (depending on search mode) with the
current search string used as the string to replace. See Query Replace.
Entering <RET> when the search string is empty launches nonincremental search (see Nonincremental Search).
To customize the special characters that incremental search understands,
alter their bindings in the keymap isearch-mode-map. For a list
of bindings, look at the documentation of isearch-mode with
C-h f isearch-mode <RET>.
To enter non-ASCII characters in an incremental search, you must use an input method (see Input Methods). If an input method is enabled in the current buffer when you start the search, you can use it while you type the search string also. Emacs indicates that by including the input method mnemonic in its prompt, like this:
I-search [im]:
where im is the mnemonic of the active input method. You can
toggle (enable or disable) the input method while you type the search
string with C-\ (isearch-toggle-input-method). You can
turn on a certain (non-default) input method with C-^
(isearch-toggle-specified-input-method), which prompts for the
name of the input method. The input method you enable during
incremental search remains enabled in the current buffer afterwards.
The characters C-w and C-y can be used in incremental search to grab text from the buffer into the search string. This makes it convenient to search for another occurrence of text at point. C-w copies the character or word after point as part of the search string, advancing point over it. (The decision, whether to copy a character or a word, is heuristic.) Another C-s to repeat the search will then search for a string including that character or word.
C-y is similar to C-w but copies all the rest of the current line into the search string. If point is already at the end of a line, it grabs the entire next line. Both C-y and C-w convert the text they copy to lower case if the search is currently not case-sensitive; this is so the search remains case-insensitive.
C-M-w and C-M-y modify the search string by only one character at a time: C-M-w deletes the last character from the search string and C-M-y copies the character after point to the end of the search string. An alternative method to add the character after point into the search string is to enter the minibuffer by M-e and to type C-f at the end of the search string in the minibuffer.
The character M-y copies text from the kill ring into the search string. It uses the same text that C-y as a command would yank. Mouse-2 in the echo area does the same. See Yanking.
When you pause for a little while during incremental search, it
highlights all other possible matches for the search string. This
makes it easier to anticipate where you can get to by typing C-s
or C-r to repeat the search. The short delay before highlighting
other matches helps indicate which match is the current one.
If you don't like this feature, you can turn it off by setting
isearch-lazy-highlight to nil.
You can control how this highlighting looks by customizing the faces
isearch (used for the current match) and lazy-highlight
(for all the other matches). The latter is also used for other matches
inside query-replace.
Vertical scrolling during incremental search can be enabled by
setting the customizable variable isearch-allow-scroll to a
non-nil value.
You can then use the vertical scroll-bar or certain keyboard
commands such as <PRIOR> (scroll-down),
<NEXT> (scroll-up) and C-l (recenter)
within the search, thus letting you see more of the text near the
current match. You must run these commands via their key sequences to
stay in the search—typing M-x command-name will always
terminate a search.
You can give prefix arguments to these commands in the usual way. The current match cannot be scrolled out of the window—this is intentional.
Several other commands, such as C-x 2
(split-window-vertically) and C-x ^
(enlarge-window) which don't scroll the window, are
nevertheless made available under this rubric, since they are likewise
handy during a search.
You can make other commands usable within an incremental search by
giving the command a non-nil isearch-scroll property.
For example, to make C-h l usable within an incremental search
in all future Emacs sessions, use C-h c to find what command it
runs. (You type C-h c C-h l; it says view-lossage.) Then
you can put the following line in your .emacs file (see Init File):
(put 'view-lossage 'isearch-scroll t)
This works for commands that don't permanently change point, the buffer contents, the match data, the current buffer, or the selected window and frame. The command must not delete the current window and must not itself attempt an incremental search.
Incremental search on a slow terminal uses a modified style of display that is designed to take less time. Instead of redisplaying the buffer at each place the search gets to, it creates a new single-line window and uses that to display the line that the search has found. The single-line window comes into play as soon as point moves outside of the text that is already on the screen.
When you terminate the search, the single-line window is removed. Emacs then redisplays the window in which the search was done, to show its new position of point.
The slow terminal style of display is used when the terminal baud rate is
less than or equal to the value of the variable search-slow-speed,
initially 1200. See also the discussion of the variable baud-rate
(see Customization of Display).
The number of lines to use in slow terminal search display is controlled
by the variable search-slow-window-lines. Its normal value is 1.
Emacs also has conventional nonincremental search commands, which require you to type the entire search string before searching begins.
To do a nonincremental search, first type C-s <RET>. This enters the minibuffer to read the search string; terminate the string with <RET>, and then the search takes place. If the string is not found, the search command signals an error.
When you type C-s <RET>, the C-s invokes incremental
search as usual. That command is specially programmed to invoke
nonincremental search, search-forward, if the string you
specify is empty. (Such an empty argument would otherwise be
useless.) But it does not call search-forward right away. First
it checks the next input character to see if is C-w,
which specifies a word search.
C-r <RET> does likewise, for a reverse incremental search.
Forward and backward nonincremental searches are implemented by the
commands search-forward and search-backward. These
commands may be bound to keys in the usual manner. The feature that you
can get to them via the incremental search commands exists for
historical reasons, and to avoid the need to find key sequences
for them.
Word search searches for a sequence of words without regard to how the words are separated. More precisely, you type a string of many words, using single spaces to separate them, and the string can be found even if there are multiple spaces, newlines, or other punctuation characters between these words.
Word search is useful for editing a printed document made with a text formatter. If you edit while looking at the printed, formatted version, you can't tell where the line breaks are in the source file. With word search, you can search without having to know them.
Word search is a special case of nonincremental search and is invoked with C-s <RET> C-w. This is followed by the search string, which must always be terminated with <RET>. Being nonincremental, this search does not start until the argument is terminated. It works by constructing a regular expression and searching for that; see Regexp Search.
Use C-r <RET> C-w to do backward word search.
Forward and backward word searches are implemented by the commands
word-search-forward and word-search-backward. These
commands may be bound to keys in the usual manner. They are available
via the incremental search commands both for historical reasons and
to avoid the need to find suitable key sequences for them.
A regular expression (regexp, for short) is a pattern that denotes a class of alternative strings to match, possibly infinitely many. GNU Emacs provides both incremental and nonincremental ways to search for a match for a regexp. The syntax of regular expressions is explained in the following section.
Incremental search for a regexp is done by typing C-M-s
(isearch-forward-regexp), by invoking C-s with a
prefix argument (whose value does not matter), or by typing M-r
within a forward incremental search. This command reads a
search string incrementally just like C-s, but it treats the
search string as a regexp rather than looking for an exact match
against the text in the buffer. Each time you add text to the search
string, you make the regexp longer, and the new regexp is searched
for. To search backward for a regexp, use C-M-r
(isearch-backward-regexp), C-r with a prefix argument,
or M-r within a backward incremental search.
All of the control characters that do special things within an ordinary incremental search have the same function in incremental regexp search. Typing C-s or C-r immediately after starting the search retrieves the last incremental search regexp used; that is to say, incremental regexp and non-regexp searches have independent defaults. They also have separate search rings that you can access with M-p and M-n.
If you type <SPC> in incremental regexp search, it matches any
sequence of whitespace characters, including newlines. If you want to
match just a space, type C-q <SPC>. You can control what a
bare spece matches by setting the variable
search-whitespace-regexp to the desired regexp.
Note that adding characters to the regexp in an incremental regexp search can make the cursor move back and start again. For example, if you have searched for ‘foo’ and you add ‘\|bar’, the cursor backs up in case the first ‘bar’ precedes the first ‘foo’.
Nonincremental search for a regexp is done by the functions
re-search-forward and re-search-backward. You can invoke
these with M-x, or bind them to keys, or invoke them by way of
incremental regexp search with C-M-s <RET> and C-M-r
<RET>.
If you use the incremental regexp search commands with a prefix
argument, they perform ordinary string search, like
isearch-forward and isearch-backward. See Incremental Search.
This manual describes regular expression features that users typically want to use. There are additional features that are mainly used in Lisp programs; see Regular Expressions.
Regular expressions have a syntax in which a few characters are special constructs and the rest are ordinary. An ordinary character is a simple regular expression which matches that same character and nothing else. The special characters are ‘$’, ‘^’, ‘.’, ‘*’, ‘+’, ‘?’, ‘[’, ‘]’ and ‘\’. Any other character appearing in a regular expression is ordinary, unless a ‘\’ precedes it. (When you use regular expressions in a Lisp program, each ‘\’ must be doubled, see the example near the end of this section.)
For example, ‘f’ is not a special character, so it is ordinary, and therefore ‘f’ is a regular expression that matches the string ‘f’ and no other string. (It does not match the string ‘ff’.) Likewise, ‘o’ is a regular expression that matches only ‘o’. (When case distinctions are being ignored, these regexps also match ‘F’ and ‘O’, but we consider this a generalization of “the same string,” rather than an exception.)
Any two regular expressions a and b can be concatenated. The result is a regular expression which matches a string if a matches some amount of the beginning of that string and b matches the rest of the string.
As a simple example, we can concatenate the regular expressions ‘f’ and ‘o’ to get the regular expression ‘fo’, which matches only the string ‘fo’. Still trivial. To do something nontrivial, you need to use one of the special characters. Here is a list of them.
‘*’ always applies to the smallest possible preceding expression. Thus, ‘fo*’ has a repeating ‘o’, not a repeating ‘fo’. It matches ‘f’, ‘fo’, ‘foo’, and so on.
The matcher processes a ‘*’ construct by matching, immediately,
as many repetitions as can be found. Then it continues with the rest
of the pattern. If that fails, backtracking occurs, discarding some
of the matches of the ‘*’-modified construct in case that makes
it possible to match the rest of the pattern. For example, in matching
‘ca*ar’ against the string ‘caaar’, the ‘a*’ first
tries to match all three ‘a’s; but the rest of the pattern is
‘ar’ and there is only ‘r’ left to match, so this try fails.
The next alternative is for ‘a*’ to match only two ‘a’s.
With this choice, the rest of the regexp matches successfully.
Thus, both ‘ab*’ and ‘ab*?’ can match the string ‘a’ and the string ‘abbbb’; but if you try to match them both against the text ‘abbb’, ‘ab*’ will match it all (the longest valid match), while ‘ab*?’ will match just ‘a’ (the shortest valid match).
Non-greedy operators match the shortest possible string starting at a
given starting point; in a forward search, though, the earliest
possible starting point for match is always the one chosen. Thus, if
you search for ‘a.*?$’ against the text ‘abbab’ followed by
a newline, it matches the whole string. Since it can match
starting at the first ‘a’, it does.
Thus, ‘[ad]’ matches either one ‘a’ or one ‘d’, and ‘[ad]*’ matches any string composed of just ‘a’s and ‘d’s (including the empty string), from which it follows that ‘c[ad]*r’ matches ‘cr’, ‘car’, ‘cdr’, ‘caddaar’, etc.
You can also include character ranges in a character set, by writing the starting and ending characters with a ‘-’ between them. Thus, ‘[a-z]’ matches any lower-case ASCII letter. Ranges may be intermixed freely with individual characters, as in ‘[a-z$%.]’, which matches any lower-case ASCII letter or ‘$’, ‘%’ or period.
Note that the usual regexp special characters are not special inside a character set. A completely different set of special characters exists inside character sets: ‘]’, ‘-’ and ‘^’.
To include a ‘]’ in a character set, you must make it the first character. For example, ‘[]a]’ matches ‘]’ or ‘a’. To include a ‘-’, write ‘-’ as the first or last character of the set, or put it after a range. Thus, ‘[]-]’ matches both ‘]’ and ‘-’.
To include ‘^’ in a set, put it anywhere but at the beginning of the set. (At the beginning, it complements the set—see below.)
When you use a range in case-insensitive search, you should write both
ends of the range in upper case, or both in lower case, or both should
be non-letters. The behavior of a mixed-case range such as ‘A-z’
is somewhat ill-defined, and it may change in future Emacs versions.
‘^’ is not special in a character set unless it is the first character. The character following the ‘^’ is treated as if it were first (in other words, ‘-’ and ‘]’ are not special there).
A complemented character set can match a newline, unless newline is
mentioned as one of the characters not to match. This is in contrast to
the handling of regexps in programs such as grep.
For historical compatibility reasons, ‘^’ can be used with this
meaning only at the beginning of the regular expression, or after
‘\(’ or ‘\|’.
For historical compatibility reasons, ‘$’ can be used with this
meaning only at the end of the regular expression, or before ‘\)’
or ‘\|’.
Because ‘\’ quotes special characters, ‘\$’ is a regular expression that matches only ‘$’, and ‘\[’ is a regular expression that matches only ‘[’, and so on.
See the following section for the special constructs that begin with ‘\’.
Note: for historical compatibility, special characters are treated as ordinary ones if they are in contexts where their special meanings make no sense. For example, ‘*foo’ treats ‘*’ as ordinary since there is no preceding expression on which the ‘*’ can act. It is poor practice to depend on this behavior; it is better to quote the special character anyway, regardless of where it appears.
For the most part, ‘\’ followed by any character matches only that character. However, there are several exceptions: two-character sequences starting with ‘\’ that have special meanings. The second character in the sequence is always an ordinary character when used on its own. Here is a table of ‘\’ constructs.
Thus, ‘foo\|bar’ matches either ‘foo’ or ‘bar’ but no other string.
‘\|’ applies to the largest possible surrounding expressions. Only a surrounding ‘\( ... \)’ grouping can limit the grouping power of ‘\|’.
Full backtracking capability exists to handle multiple uses of ‘\|’.
This last application is not a consequence of the idea of a
parenthetical grouping; it is a separate feature that is assigned as a
second meaning to the same ‘\( ... \)’ construct. In practice
there is usually no conflict between the two meanings; when there is
a conflict, you can use a “shy” group.
After the end of a ‘\( ... \)’ construct, the matcher remembers the beginning and end of the text matched by that construct. Then, later on in the regular expression, you can use ‘\’ followed by the digit d to mean “match the same text matched the dth time by the ‘\( ... \)’ construct.”
The strings matching the first nine ‘\( ... \)’ constructs appearing in a regular expression are assigned numbers 1 through 9 in the order that the open-parentheses appear in the regular expression. So you can use ‘\1’ through ‘\9’ to refer to the text matched by the corresponding ‘\( ... \)’ constructs.
For example, ‘\(.*\)\1’ matches any newline-free string that is composed of two identical halves. The ‘\(.*\)’ matches the first half, which may be anything, but the ‘\1’ that follows must match the same exact text.
If a particular ‘\( ... \)’ construct matches more than once
(which can easily happen if it is followed by ‘*’), only the last
match is recorded.
‘\b’ matches at the beginning or end of the buffer
regardless of what text appears next to it.
The constructs that pertain to words and syntax are controlled by the setting of the syntax table (see Syntax).
Here is a complicated regexp—a simplified version of the regexp that Emacs uses, by default, to recognize the end of a sentence together with any whitespace that follows. We show its Lisp syntax to distinguish the spaces from the tab characters. In Lisp syntax, the string constant begins and ends with a double-quote. ‘\"’ stands for a double-quote as part of the regexp, ‘\\’ for a backslash as part of the regexp, ‘\t’ for a tab, and ‘\n’ for a newline.
"[.?!][]\"')]*\\($\\| $\\|\t\\| \\)[ \t\n]*"
This contains four parts in succession: a character set matching period, ‘?’, or ‘!’; a character set matching close-brackets, quotes, or parentheses, repeated zero or more times; a set of alternatives within backslash-parentheses that matches either end-of-line, a space at the end of a line, a tab, or two spaces; and a character set matching whitespace characters, repeated any number of times.
To enter the same regexp in incremental search, you would type <TAB> to enter a tab, and C-j to enter a newline. You would also type single backslashes as themselves, instead of doubling them for Lisp syntax. In commands that use ordinary minibuffer input to read a regexp, you would quote the C-j by preceding it with a C-q to prevent C-j from exiting the minibuffer.
Incremental searches in Emacs normally ignore the case of the text they are searching through, if you specify the text in lower case. Thus, if you specify searching for ‘foo’, then ‘Foo’ and ‘foo’ are also considered a match. Regexps, and in particular character sets, are included: ‘[ab]’ would match ‘a’ or ‘A’ or ‘b’ or ‘B’.
An upper-case letter anywhere in the incremental search string makes the search case-sensitive. Thus, searching for ‘Foo’ does not find ‘foo’ or ‘FOO’. This applies to regular expression search as well as to string search. The effect ceases if you delete the upper-case letter from the search string.
Typing M-c within an incremental search toggles the case sensitivity of that search. The effect does not extend beyond the current incremental search to the next one, but it does override the effect of including an upper-case letter in the current search.
If you set the variable case-fold-search to nil, then
all letters must match exactly, including case. This is a per-buffer
variable; altering the variable affects only the current buffer, but
there is a default value in default-case-fold-search that you
can also set. See Locals. This variable applies to nonincremental
searches also, including those performed by the replace commands
(see Replace) and the minibuffer history matching commands
(see Minibuffer History).
Several related variables control case-sensitivity of searching and
matching for specific commands or activities. For instance,
tags-case-fold-search controls case sensitivity for
find-tag. To find these variables, do M-x
apropos-variable <RET> case-fold-search <RET>.
Global search-and-replace operations are not needed often in Emacs,
but they are available. In addition to the simple M-x
replace-string command which replaces all occurrences,
there is M-% (query-replace), which presents each occurrence
of the pattern and asks you whether to replace it.
The replace commands normally operate on the text from point to the
end of the buffer; however, in Transient Mark mode (see Transient Mark), when the mark is active, they operate on the region. The
replace commands all replace one string (or regexp) with one
replacement string. It is possible to perform several replacements in
parallel using the command expand-region-abbrevs
(see Expanding Abbrevs).
To replace every instance of ‘foo’ after point with ‘bar’, use the command M-x replace-string with the two arguments ‘foo’ and ‘bar’. Replacement happens only in the text after point, so if you want to cover the whole buffer you must go to the beginning first. All occurrences up to the end of the buffer are replaced; to limit replacement to part of the buffer, narrow to that part of the buffer before doing the replacement (see Narrowing). In Transient Mark mode, when the region is active, replacement is limited to the region (see Transient Mark).
When replace-string exits, it leaves point at the last
occurrence replaced. It sets the mark to the prior position of point
(where the replace-string command was issued); use C-u
C-<SPC> to move back there.
A numeric argument restricts replacement to matches that are surrounded by word boundaries. The argument's value doesn't matter.
What if you want to exchange ‘x’ and ‘y’: replace every ‘x’ with a ‘y’ and vice versa? You can do it this way:
M-x replace-string <RET> x <RET> @TEMP@ <RET>
M-< M-x replace-string <RET> y <RET> x <RET>
M-< M-x replace-string <RET> @TEMP@ <RET> y <RET>
This works provided the string ‘@TEMP@’ does not appear in your text.
The M-x replace-string command replaces exact matches for a single string. The similar command M-x replace-regexp replaces any match for a specified pattern.
In replace-regexp, the newstring need not be constant:
it can refer to all or part of what is matched by the regexp.
‘\&’ in newstring stands for the entire match being
replaced. ‘\d’ in newstring, where d is a
digit, stands for whatever matched the dth parenthesized
grouping in regexp. ‘\#’ refers to the count of
replacements already made in this command, as a decimal number. In
the first replacement, ‘\#’ stands for ‘0’; in the second,
for ‘1’; and so on. For example,
M-x replace-regexp <RET> c[ad]+r <RET> \&-safe <RET>
replaces (for example) ‘cadr’ with ‘cadr-safe’ and ‘cddr’ with ‘cddr-safe’.
M-x replace-regexp <RET> \(c[ad]+r\)-safe <RET> \1 <RET>
performs the inverse transformation. To include a ‘\’ in the text to replace with, you must enter ‘\\’.
If you want to enter part of the replacement string by hand each time, use ‘\?’ in the replacement string. Each replacement will ask you to edit the replacement string in the minibuffer, putting point where the ‘\?’ was.
The remainder of this subsection is intended for specialized tasks and requires knowledge of Lisp. Most readers can skip it.
You can use Lisp expressions to calculate parts of the replacement string. To do this, write ‘\,’ followed by the expression in the replacement string. Each replacement calculates the value of the expression and converts it to text without quoting (if it's a string, this means using the string's contents), and uses it in the replacement string in place of the expression itself. If the expression is a symbol, one space in the replacement string after the symbol name goes with the symbol name, so the value replaces them both.
Inside such an expression, you can use some special sequences.
‘\&’ and ‘\n’ refer here, as usual, to the entire
match as a string, and to a submatch as a string. n may be
multiple digits, and the value of ‘\n’ is nil if
subexpression n did not match. You can also use ‘\#&’ and
‘\#n’ to refer to those matches as numbers (this is valid
when the match or submatch has the form of a numeral). ‘\#’ here
too stands for the number of already-completed replacements.
Repeating our example to exchange ‘x’ and ‘y’, we can thus do it also this way:
M-x replace-regexp <RET> \(x\)\|y <RET>
\,(if \1 "y" "x") <RET>
For computing replacement strings for ‘\,’, the format
function is often useful (see Formatting Strings). For example, to add consecutively numbered
strings like ‘ABC00042’ to columns 73 to 80 (unless they are
already occupied), you can use
M-x replace-regexp <RET> ^.\{0,72\}$ <RET>
\,(format "%-72sABC%05d" \& \#) <RET>
If the first argument of a replace command is all lower case, the
command ignores case while searching for occurrences to
replace—provided case-fold-search is non-nil. If
case-fold-search is set to nil, case is always significant
in all searches.
In addition, when the newstring argument is all or partly lower case, replacement commands try to preserve the case pattern of each occurrence. Thus, the command
M-x replace-string <RET> foo <RET> bar <RET>
replaces a lower case ‘foo’ with a lower case ‘bar’, an
all-caps ‘FOO’ with ‘BAR’, and a capitalized ‘Foo’ with
‘Bar’. (These three alternatives—lower case, all caps, and
capitalized, are the only ones that replace-string can
distinguish.)
If upper-case letters are used in the replacement string, they remain
upper case every time that text is inserted. If upper-case letters are
used in the first argument, the second argument is always substituted
exactly as given, with no case conversion. Likewise, if either
case-replace or case-fold-search is set to nil,
replacement is done without case conversion.
If you want to change only some of the occurrences of ‘foo’ to
‘bar’, not all of them, then you cannot use an ordinary
replace-string. Instead, use M-% (query-replace).
This command finds occurrences of ‘foo’ one by one, displays each
occurrence and asks you whether to replace it. Aside from querying,
query-replace works just like replace-string. It
preserves case, like replace-string, provided
case-replace is non-nil, as it normally is. A numeric
argument means consider only occurrences that are bounded by
word-delimiter characters.
C-M-% performs regexp search and replace (query-replace-regexp).
It works like replace-regexp except that it queries
like query-replace.
These commands highlight the current match using the face
query-replace. They highlight other matches using
lazy-highlight just like incremental search (see Incremental Search).
The characters you can type when you are shown a match for the string or regexp are:
You can type C-r at this point (see below) to alter the replaced
text. You can also type C-x u to undo the replacement; this exits
the query-replace, so if you want to do further replacement you
must use C-x <ESC> <ESC> <RET> to restart
(see Repetition).
Some other characters are aliases for the ones listed above: y, n and q are equivalent to <SPC>, <DEL> and <RET>.
Aside from this, any other character exits the query-replace,
and is then reread as part of a key sequence. Thus, if you type
C-k, it exits the query-replace and then kills to end of
line.
To restart a query-replace once it is exited, use C-x
<ESC> <ESC>, which repeats the query-replace because it
used the minibuffer to read its arguments. See C-x ESC ESC.
See also Transforming File Names, for Dired commands to rename, copy, or link files by replacing regexp matches in file names.
Here are some other commands that find matches for a regular
expression. They all ignore case in matching, if the pattern contains
no upper-case letters and case-fold-search is non-nil.
Aside from occur and its variants, all operate on the text from
point to the end of the buffer, or on the active region in Transient
Mark mode.
occur can not correctly
handle multiline matches.
The buffer ‘*Occur*’ containing the output serves as a menu for finding the occurrences in their original context. Click Mouse-2 on an occurrence listed in ‘*Occur*’, or position point there and type <RET>; this switches to the buffer that was searched and moves point to the original of the chosen occurrence. o and C-o display the match in another window; C-o does not select it.
Occur mode supports the next-error functionality described in
Compilation Mode.
occur, except it is able to search
through multiple buffers.
multi-occur, except the buffers to
search are specified by a regexp on their filename.
If a match is split across lines, flush-lines deletes all those
lines. It deletes the lines before starting to look for the next
match; hence, it ignores a match starting on the same line at which
another match ended.
If a match is split across lines, this command keeps all those lines.
You can also search multiple files under control of a tags table
(see Tags Search) or through the Dired A command
(see Operating on Files), or ask the grep program to do it
(see Grep Searching).
In this chapter we describe the commands that are especially useful for the times when you catch a mistake in your text just after you have made it, or change your mind while composing text on the fly.
The most fundamental command for correcting erroneous editing is the
undo command, C-x u or C-_ or C-/. This command
undoes a single command (usually), a part of a command (in the case of
query-replace), or several consecutive self-inserting
characters. Consecutive repetitions of the undo command undo earlier
and earlier changes, back to the limit of the undo information
available. See Undo, for more information.
delete-backward-char).
backward-kill-word).
backward-kill-sentence).
The <DEL> character (delete-backward-char) is the most
important correction command. It deletes the character before point.
When <DEL> follows a self-inserting character command, you can think
of it as canceling that command. However, avoid the mistake of thinking
of <DEL> as a general way to cancel a command!
When your mistake is longer than a couple of characters, it might be more convenient to use M-<DEL> or C-x <DEL>. M-<DEL> kills back to the start of the last word, and C-x <DEL> kills back to the start of the last sentence. C-x <DEL> is particularly useful when you change your mind about the phrasing of the text you are writing. M-<DEL> and C-x <DEL> save the killed text for C-y and M-y to retrieve. See Yanking.
M-<DEL> is often useful even when you have typed only a few characters wrong, if you know you are confused in your typing and aren't sure exactly what you typed. At such a time, you cannot correct with <DEL> except by looking at the screen to see what you did. Often it requires less thought to kill the whole word and start again.
transpose-chars).
transpose-words).
transpose-sexps).
transpose-lines).
The common error of transposing two characters can be fixed, when they
are adjacent, with the C-t command (transpose-chars). Normally,
C-t transposes the two characters on either side of point. When
given at the end of a line, rather than transposing the last character of
the line with the newline, which would be useless, C-t transposes the
last two characters on the line. So, if you catch your transposition error
right away, you can fix it with just a C-t. If you don't catch it so
fast, you must move the cursor back between the two transposed
characters before you type C-t. If you transposed a space with
the last character of the word before it, the word motion commands are
a good way of getting there. Otherwise, a reverse search (C-r)
is often the best way. See Search.
M-t transposes the word before point with the word after point
(transpose-words). It moves point forward over a word,
dragging the word preceding or containing point forward as well. The
punctuation characters between the words do not move. For example,
‘FOO, BAR’ transposes into ‘BAR, FOO’ rather than
‘BAR FOO,’.
C-M-t (transpose-sexps) is a similar command for
transposing two expressions (see Expressions), and C-x C-t
(transpose-lines) exchanges lines. They work like M-t
except as regards what units of text they transpose.
A numeric argument to a transpose command serves as a repeat count: it tells the transpose command to move the character (word, expression, line) before or containing point across several other characters (words, expressions, lines). For example, C-u 3 C-t moves the character before point forward across three other characters. It would change ‘f-!-oobar’ into ‘oobf-!-ar’. This is equivalent to repeating C-t three times. C-u - 4 M-t moves the word before point backward across four words. C-u - C-M-t would cancel the effect of plain C-M-t.
A numeric argument of zero is assigned a special meaning (because otherwise a command with a repeat count of zero would do nothing): to transpose the character (word, expression, line) ending after point with the one ending after the mark.
A very common error is to type words in the wrong case. Because of this, the word case-conversion commands M-l, M-u and M-c have a special feature when used with a negative argument: they do not move the cursor. As soon as you see you have mistyped the last word, you can simply case-convert it and go on typing. See Case.
This section describes the commands to check the spelling of a single word or of a portion of a buffer. These commands work with the spelling checker program Ispell, which is not part of Emacs.
ispell-word).
ispell-complete-word).
Flyspell mode is a fully-automatic way to check spelling as you edit in Emacs. It operates by checking words as you change or insert them. When it finds a word that it does not recognize, it highlights that word. This does not interfere with your editing, but when you see the highlighted word, you can move to it and fix it. Type M-x flyspell-mode to enable or disable this mode in the current buffer.
When Flyspell mode highlights a word as misspelled, you can click on it with Mouse-2 to display a menu of possible corrections and actions. You can also correct the word by editing it manually in any way you like.
Flyspell Prog mode works just like ordinary Flyspell mode, except that it only checks words in comments and string constants. This feature is useful for editing programs. Type M-x flyspell-prog-mode to enable or disable this mode in the current buffer.
The other Emacs spell-checking features check or look up words when you give an explicit command to do so.
To check the spelling of the word around or before point, and
optionally correct it as well, use the command M-$
(ispell-word). If the word is not correct, the command offers
you various alternatives for what to do about it.
To check the entire current buffer, use M-x ispell-buffer. Use M-x ispell-region to check just the current region. To check spelling in an email message you are writing, use M-x ispell-message; that command checks the whole buffer, except for material that is indented or appears to be cited from other messages.
The M-x ispell command spell-checks the active region if the Transient Mark mode is on (see Transient Mark), otherwise it spell-checks the current buffer.
Each time these commands encounter an incorrect word, they ask you what to do. They display a list of alternatives, usually including several “near-misses”—words that are close to the word being checked. Then you must type a single-character response. Here are the valid responses:
query-replace so you
can replace it elsewhere in the buffer if you wish. (The replacements
will be rescanned for more spelling errors.)
The command ispell-complete-word, which is bound to the key
M-<TAB> in Text mode and related modes, shows a list of
completions based on spelling correction. Insert the beginning of a
word, and then type M-<TAB>; the command displays a
completion list window. (If your window manager intercepts
M-<TAB>, type <ESC> <TAB> or C-M-i.) To
choose one of the completions listed, click Mouse-2 or
Mouse-1 fast on it, or move the cursor there in the completions
window and type <RET>. See Text Mode.
Once started, the Ispell subprocess continues to run (waiting for something to do), so that subsequent spell checking commands complete more quickly. If you want to get rid of the Ispell process, use M-x ispell-kill-ispell. This is not usually necessary, since the process uses no time except when you do spelling correction.
Ispell uses two dictionaries together for spell checking: the
standard dictionary and your private dictionary. The variable
ispell-dictionary specifies the file name to use for the
standard dictionary; a value of nil selects the default
dictionary. The command M-x ispell-change-dictionary sets this
variable and then restarts the Ispell subprocess, so that it will use
a different standard dictionary.
Ispell uses a separate dictionary for word completion. The variable
ispell-complete-word-dict specifies the file name of this
dictionary. The completion dictionary must be different because it
cannot use root and affix information. For some languages
there is a spell checking dictionary but no word completion
dictionary.
In this chapter we describe how a sequence of editing commands can be recorded and repeated multiple times.
A keyboard macro is a command defined by the user to stand for another sequence of keys. For example, if you discover that you are about to type C-n C-d forty times, you can speed your work by defining a keyboard macro to do C-n C-d and calling it with a repeat count of forty.
You define a keyboard macro while executing the commands which are the definition. Put differently, as you define a keyboard macro, the definition is being executed for the first time. This way, you can see what the effects of your commands are, so that you don't have to figure them out in your head. When you are finished, the keyboard macro is defined and also has been, in effect, executed once. You can then do the whole thing over again by invoking the macro.
Keyboard macros differ from ordinary Emacs commands in that they are written in the Emacs command language rather than in Lisp. This makes it easier for the novice to write them, and makes them more convenient as temporary hacks. However, the Emacs command language is not powerful enough as a programming language to be useful for writing anything intelligent or general. For such things, Lisp must be used.
kmacro-start-macro).
kmacro-end-macro).
kmacro-end-and-call-macro).
First end the definition of the keyboard macro, if currently defining it.
To immediately execute the keyboard macro again, just repeat the e.
kmacro-end-or-call-macro).
kbd-macro-query).
kmacro-name-last-macro).
kmacro-bind-to-key).
edit-kbd-macro).
apply-macro-to-region-lines).
To start defining a keyboard macro, type the C-x ( command
(kmacro-start-macro). From then on, your keys continue to be
executed, but also become part of the definition of the macro. ‘Def’
appears in the mode line to remind you of what is going on. When you are
finished, the C-x ) command (kmacro-end-macro) terminates the
definition (without becoming part of it!). For example,
C-x ( M-f foo C-x )
defines a macro to move forward a word and then insert ‘foo’.
The macro thus defined can be invoked again with the C-x e
command (kmacro-end-and-call-macro), which may be given a
repeat count as a numeric argument to execute the macro many times.
If you enter C-x e while defining a macro, the macro is
terminated and executed immediately.
After executing the macro with C-x e, you can use e repeatedly to immediately repeat the macro one or more times. For example,
C-x ( xyz C-x e e e
inserts ‘xyzxyzxyzxyz’ in the current buffer.
C-x ) can also be given a repeat count as an argument, in which case it repeats the macro that many times right after defining it, but defining the macro counts as the first repetition (since it is executed as you define it). Therefore, giving C-x ) an argument of 4 executes the macro immediately 3 additional times. An argument of zero to C-x e or C-x ) means repeat the macro indefinitely (until it gets an error or you type C-g or, on MS-DOS, C-<BREAK>).
The key <F4> is like a combination of C-x ) and C-x e. If you're defining a macro, <F4> ends the definition. Otherwise it executes the last macro.
If you wish to repeat an operation at regularly spaced places in the text, define a macro and include as part of the macro the commands to move to the next place you want to use it. For example, if you want to change each line, you should position point at the start of a line, and define a macro to change that line and leave point at the start of the next line. Then repeating the macro will operate on successive lines.
When a command reads an argument with the minibuffer, your minibuffer input becomes part of the macro along with the command. So when you replay the macro, the command gets the same argument as when you entered the macro. For example,
C-x ( C-a C-<SPC> C-n M-w C-x b f o o <RET> C-y C-x b <RET> C-x )
defines a macro that copies the current line into the buffer ‘foo’, then returns to the original buffer.
You can use function keys in a keyboard macro, just like keyboard keys. You can even use mouse events, but be careful about that: when the macro replays the mouse event, it uses the original mouse position of that event, the position that the mouse had while you were defining the macro. The effect of this may be hard to predict. (Using the current mouse position would be even less predictable.)
One thing that doesn't always work well in a keyboard macro is the
command C-M-c (exit-recursive-edit). When this command
exits a recursive edit that started within the macro, it works as you'd
expect. But if it exits a recursive edit that started before you
invoked the keyboard macro, it also necessarily exits the keyboard macro
as part of the process.
After you have terminated the definition of a keyboard macro, you can add to the end of its definition by typing C-u C-x (. This is equivalent to plain C-x ( followed by retyping the whole definition so far. As a consequence it re-executes the macro as previously defined.
You can also add to the end of the definition of the last keyboard macro without re-executing it by typing C-u C-u C-x (.
The variable kmacro-execute-before-append specifies whether
a single C-u prefix causes the existing macro to be re-executed
before appending to it.
The command C-x C-k r (apply-macro-to-region-lines)
repeats the last defined keyboard macro on each line that begins in
the region. It does this line by line, by moving point to the
beginning of the line and then executing the macro.
All defined keyboard macros are recorded in the “keyboard macro ring”, a list of sequences of keys. There is only one keyboard macro ring, shared by all buffers.
All commands which operate on the keyboard macro ring use the same C-x C-k prefix. Most of these commands can be executed and repeated immediately after each other without repeating the C-x C-k prefix. For example,
C-x C-k C-p C-p C-k C-k C-k C-n C-n C-k C-p C-k C-d
will rotate the keyboard macro ring to the “second previous” macro, execute the resulting head macro three times, rotate back to the original head macro, execute that once, rotate to the “previous” macro, execute that, and finally delete it from the macro ring.
The command C-x C-k C-k (kmacro-end-or-call-macro-repeat)
executes the keyboard macro at the head of the macro ring. You can
repeat the macro immediately by typing another C-k, or you can
rotate the macro ring immediately by typing C-n or C-p.
When a keyboard macro is being defined, C-x C-k C-k behaves like C-x ) except that, immediately afterward, you can use most key bindings of this section without the C-x C-k prefix. For instance, another C-k will re-execute the macro.
The commands C-x C-k C-n (kmacro-cycle-ring-next) and
C-x C-k C-p (kmacro-cycle-ring-previous) rotate the
macro ring, bringing the next or previous keyboard macro to the head
of the macro ring. The definition of the new head macro is displayed
in the echo area. You can continue to rotate the macro ring
immediately by repeating just C-n and C-p until the
desired macro is at the head of the ring. To execute the new macro
ring head immediately, just type C-k.
Note that Emacs treats the head of the macro ring as the “last defined keyboard macro”. For instance, it is the keyboard macro that C-x e will execute.
The command C-x C-k C-v (kmacro-view-macro-repeat)
displays the last keyboard macro, or when repeated (with C-v),
it displays the previous macro on the macro ring, just like C-x
C-k C-p, but without actually rotating the macro ring. If you enter
C-k immediately after displaying a macro from the ring, that
macro is executed, but still without altering the macro ring.
So while e.g. C-x C-k C-p C-p C-p C-k C-k makes the 3rd previous macro the current macro and executes it twice, C-x C-k C-v C-v C-v C-k C-k will display and execute the 3rd previous macro once and then the current macro once.
The command C-x C-k C-d (kmacro-delete-ring-head)
removes and deletes the macro currently at the head of the macro
ring. You can use this to delete a macro that didn't work as
expected, or which you don't need anymore.
The command C-x C-k C-t (kmacro-swap-ring)
interchanges the head of the macro ring with the previous element on
the macro ring.
The command C-x C-k C-l (kmacro-call-ring-2nd-repeat)
executes the previous (rather than the head) element on the macro ring.
The maximum number of macros stored in the keyboard macro ring is
determined by the customizable variable kmacro-ring-max.
Each keyboard macro has an associated counter. Normally, the macro counter is initialized to 0 when you start defining the macro, and incremented by 1 after each insertion of the counter value; that is, if you insert the macro counter twice while defining the macro, the counter will increase by 2 on each repetition of the macro.
The command C-x C-k C-i (kmacro-insert-counter) inserts
the current value of the keyboard macro counter and increments the
counter by 1. You can use a numeric prefix argument to specify a
different increment. If you just specify a C-u prefix, the last
inserted counter value is repeated and the counter is not incremented.
For example, if you enter the following sequence while defining a macro
C-x C-k C-i C-x C-k C-i C-u C-x C-k C-i C-x C-k C-i
the text ‘0112’ is inserted in the buffer, and for the first and second execution of the macro ‘3445’ and ‘6778’ are inserted.
This command usually only makes sense while defining a keyboard macro. But its behavior when no keyboard macro is being defined or executed is predictable: it inserts and increments the counter of the head of the keyboard macro ring.
The command C-x C-k C-c (kmacro-set-counter) prompts
for the initial value of the keyboard macro counter if you use it
before you define a keyboard macro. If you use it before executing a
keyboard macro, it resets that macro's counter. If you use it while
defining a keyboard macro, then the macro counter gets reset to that same
value on each repetition of the macro. Rather than having the command
prompt for a value, you can also specify the value with a numeric
prefix argument. If you just specify a C-u prefix, the counter
is reset to the value it had prior to the current repetition of the
macro (undoing any increments so far in this repetition). If you just
specify a C-u prefix while no macro is being defined or executed,
then the new value of the counter is essentially unpredictable.
The command C-x C-k C-a (kmacro-add-counter) prompts
for a value to add to the macro counter. You can also specify the
value with a numeric prefix argument. If you just specify a C-u
prefix, the counter is reset to the last value inserted by any
keyboard macro. Usually, this will only make sense if that value was
inserted during the current macro definition or repetition.
This command normally only makes sense while defining a keyboard macro. But its behavior when no keyboard macro is being defined or executed is predictable: it affects the counter of the head of the keyboard macro ring.
The command C-x C-k C-f (kmacro-set-format) prompts for
the format to use when inserting the macro counter. The default
format is ‘%d’, which means to insert the number in decimal
without any padding. You can exit with empty minibuffer to reset the
format to this default. You can specify any format string that the
format function accepts and that makes sense with a single
integer extra argument (see Formatting Strings). Do not put the format string inside double
quotes when you insert it in the minibuffer.
If you use this command while no keyboard macro is being defined or executed, the new format affects all subsequent macro definitions. Existing macros continue to use the format in effect when they were defined. If you set the format while defining a keyboard macro, this affects the macro being defined from that point on, but it does not affect subsequent macros. Execution of the macro will, at each step, use the format in effect at that step during its definition. Changes to the macro format during execution of a macro, like the corresponding changes during its definition, have no effect on subsequent macros.
The format set by C-x C-k C-f does not affect insertion of numbers stored in registers.
Using C-x q (kbd-macro-query), you can get an effect
similar to that of query-replace, where the macro asks you each
time around whether to make a change. While defining the macro,
type C-x q at the point where you want the query to occur. During
macro definition, the C-x q does nothing, but when you run the
macro later, C-x q asks you interactively whether to continue.
The valid responses when C-x q asks are <SPC> (or y),
<DEL> (or n), <RET> (or q), C-l and C-r.
The answers are the same as in query-replace, though not all of
the query-replace options are meaningful.
These responses include <SPC> to continue, and <DEL> to skip the remainder of this repetition of the macro and start right away with the next repetition. <RET> means to skip the remainder of this repetition and cancel further repetitions. C-l redraws the screen and asks you again for a character to say what to do.
C-r enters a recursive editing level, in which you can perform editing which is not part of the macro. When you exit the recursive edit using C-M-c, you are asked again how to continue with the keyboard macro. If you type a <SPC> at this time, the rest of the macro definition is executed. It is up to you to leave point and the text in a state such that the rest of the macro will do what you want.
C-u C-x q, which is C-x q with a numeric argument, performs a completely different function. It enters a recursive edit reading input from the keyboard, both when you type it during the definition of the macro, and when it is executed from the macro. During definition, the editing you do inside the recursive edit does not become part of the macro. During macro execution, the recursive edit gives you a chance to do some particularized editing on each repetition. See Recursive Edit.
Another way to vary the behavior of a keyboard macro is to use a register as a counter, incrementing it on each repetition of the macro. See RegNumbers.
If you wish to save a keyboard macro for later use, you can give it
a name using C-x C-k n (kmacro-name-last-macro).
This reads a name as an argument using the minibuffer and defines that
name to execute the last keyboard macro, in its current form. (If you
later add to the definition of this macro, that does not alter the
name's definition as a macro.) The macro name is a Lisp symbol, and
defining it in this way makes it a valid command name for calling with
M-x or for binding a key to with global-set-key
(see Keymaps). If you specify a name that has a prior definition
other than a keyboard macro, an error message is shown and nothing is
changed.
You can also bind the last keyboard macro (in its current form) to a
key, using C-x C-k b (kmacro-bind-to-key) followed by the
key sequence you want to bind. You can bind to any key sequence in
the global keymap, but since most key sequences already have other
bindings, you should select the key sequence carefully. If you try to
bind to a key sequence with an existing binding (in any keymap), this
command asks you for confirmation before replacing the existing binding.
To avoid problems caused by overriding existing bindings, the key sequences C-x C-k 0 through C-x C-k 9 and C-x C-k A through C-x C-k Z are reserved for your own keyboard macro bindings. In fact, to bind to one of these key sequences, you only need to type the digit or letter rather than the whole key sequences. For example,
C-x C-k b 4
will bind the last keyboard macro to the key sequence C-x C-k 4.
Once a macro has a command name, you can save its definition in a file. Then it can be used in another editing session. First, visit the file you want to save the definition in. Then use this command:
M-x insert-kbd-macro <RET> macroname <RET>
This inserts some Lisp code that, when executed later, will define the
same macro with the same definition it has now. (You need not
understand Lisp code to do this, because insert-kbd-macro writes
the Lisp code for you.) Then save the file. You can load the file
later with load-file (see Lisp Libraries). If the file you
save in is your init file ~/.emacs (see Init File) then the
macro will be defined each time you run Emacs.
If you give insert-kbd-macro a numeric argument, it makes
additional Lisp code to record the keys (if any) that you have bound
to macroname, so that the macro will be reassigned the same keys
when you load the file.
You can edit the last keyboard macro by typing C-x C-k C-e or
C-x C-k RET (kmacro-edit-macro). This formats the macro
definition in a buffer and enters a specialized major mode for editing
it. Type C-h m once in that buffer to display details of how to
edit the macro. When you are finished editing, type C-c C-c.
You can edit a named keyboard macro or a macro bound to a key by typing
C-x C-k e (edit-kbd-macro). Follow that with the
keyboard input that you would use to invoke the macro—C-x e or
M-x name or some other key sequence.
You can edit the last 100 keystrokes as a macro by typing
C-x C-k l (kmacro-edit-lossage).
You can interactively replay and edit the last keyboard
macro, one command at a time, by typing C-x C-k SPC
(kmacro-step-edit-macro). Unless you quit the macro using
q or C-g, the edited macro replaces the last macro on the
macro ring.
This macro editing feature shows the last macro in the minibuffer together with the first (or next) command to be executed, and prompts you for an action. You can enter ? to get a summary of your options. These actions are available:
self-insert-command commands).
The operating system stores data permanently in named files, so most of the text you edit with Emacs comes from a file and is ultimately stored in a file.
To edit a file, you must tell Emacs to read the file and prepare a buffer containing a copy of the file's text. This is called visiting the file. Editing commands apply directly to text in the buffer; that is, to the copy inside Emacs. Your changes appear in the file itself only when you save the buffer back into the file.
In addition to visiting and saving files, Emacs can delete, copy, rename, and append to files, keep multiple versions of them, and operate on file directories.
Most Emacs commands that operate on a file require you to specify the
file name. (Saving and reverting are exceptions; the buffer knows which
file name to use for them.) You enter the file name using the
minibuffer (see Minibuffer). Completion is available
(see Completion) to make it easier to specify long file names. When
completing file names, Emacs ignores those whose file-name extensions
appear in the variable completion-ignored-extensions; see
Completion Options.
For most operations, there is a default file name which is used if you type just <RET> to enter an empty argument. Normally the default file name is the name of the file visited in the current buffer; this makes it easy to operate on that file with any of the Emacs file commands.
Each buffer has a default directory which is normally the same as the
directory of the file visited in that buffer. When you enter a file
name without a directory, the default directory is used. If you specify
a directory in a relative fashion, with a name that does not start with
a slash, it is interpreted with respect to the default directory. The
default directory is kept in the variable default-directory,
which has a separate value in every buffer.
For example, if the default file name is /u/rms/gnu/gnu.tasks then the default directory is /u/rms/gnu/. If you type just ‘foo’, which does not specify a directory, it is short for /u/rms/gnu/foo. ‘../.login’ would stand for /u/rms/.login. ‘new/foo’ would stand for the file name /u/rms/gnu/new/foo.
The command M-x pwd displays the current buffer's default
directory, and the command M-x cd sets it (to a value read using
the minibuffer). A buffer's default directory changes only when the
cd command is used. A file-visiting buffer's default directory
is initialized to the directory of the file that is visited in that buffer. If
you create a buffer with C-x b, its default directory is copied
from that of the buffer that was current at the time.
The default directory actually appears in the minibuffer when the
minibuffer becomes active to read a file name. This serves two
purposes: it shows you what the default is, so that you can type
a relative file name and know with certainty what it will mean, and it
allows you to edit the default to specify a different directory.
This insertion of the default directory is inhibited if the variable
insert-default-directory is set to nil.
Note that it is legitimate to type an absolute file name after you enter the minibuffer, ignoring the presence of the default directory name as part of the text. The final minibuffer contents may look invalid, but that is not so. For example, if the minibuffer starts out with ‘/usr/tmp/’ and you add ‘/x1/rms/foo’, you get ‘/usr/tmp//x1/rms/foo’; but Emacs ignores everything through the first slash in the double slash; the result is ‘/x1/rms/foo’. See Minibuffer File.
‘$’ in a file name is used to substitute an environment variable. The environment variable name consists of all the alphanumeric characters after the ‘$’; alternatively, it can be enclosed in braces after the ‘$’. For example, if you have used the shell command export FOO=rms/hacks to set up an environment variable named FOO, then you can use /u/$FOO/test.c or /u/${FOO}/test.c as an abbreviation for /u/rms/hacks/test.c. If the environment variable is not defined, no substitution occurs: /u/$notdefined stands for itself (assuming the environment variable notdefined is not defined).
Note that shell commands to set environment variables affect Emacs only when done before Emacs is started.
You can use ~/ in a file name to mean your home directory,
or ~user-id/ to mean the home directory of a user whose
login name is user-id. (On DOS and Windows systems, where a user
doesn't have a home directory, Emacs substitutes ~/ with the
value of the environment variable HOME; see General Variables.)
To access a file with ‘$’ in its name, if the ‘$’ causes expansion, type ‘$$’. This pair is converted to a single ‘$’ at the same time as variable substitution is performed for a single ‘$’. Alternatively, quote the whole file name with ‘/:’ (see Quoted File Names). File names which begin with a literal ‘~’ should also be quoted with ‘/:’.
The Lisp function that performs the substitution is called
substitute-in-file-name. The substitution is performed only on
file names read as such using the minibuffer.
You can include non-ASCII characters in file names if you set the
variable file-name-coding-system to a non-nil value.
See Specify Coding.
find-file).
find-file-read-only).
find-alternate-file).
find-file-other-window). Don't
alter what is displayed in the selected window.
find-file-other-frame). Don't
alter what is displayed in the selected frame.
Visiting a file means copying its contents into an Emacs buffer so you can edit them. Emacs makes a new buffer for each file that you visit. We often say that this buffer “is visiting” that file, or that the buffer's “visited file” is that file. Emacs constructs the buffer name from the file name by throwing away the directory, keeping just the name proper. For example, a file named /usr/rms/emacs.tex would get a buffer named ‘emacs.tex’. If there is already a buffer with that name, Emacs constructs a unique name—the normal method is to append ‘<2>’, ‘<3>’, and so on, but you can select other methods (see Uniquify).
Each window's mode line shows the name of the buffer that is being displayed in that window, so you can always tell what buffer you are editing.
The changes you make with editing commands are made in the Emacs buffer. They do not take effect in the file that you visited, or any place permanent, until you save the buffer. Saving the buffer means that Emacs writes the current contents of the buffer into its visited file. See Saving.
If a buffer contains changes that have not been saved, we say the buffer is modified. This is important because it implies that some changes will be lost if the buffer is not saved. The mode line displays two stars near the left margin to indicate that the buffer is modified.
To visit a file, use the command C-x C-f (find-file). Follow
the command with the name of the file you wish to visit, terminated by a
<RET>.
The file name is read using the minibuffer (see Minibuffer), with defaulting and completion in the standard manner (see File Names). While in the minibuffer, you can abort C-x C-f by typing C-g. File-name completion ignores certain filenames; for more about this, see Completion Options.
Your confirmation that C-x C-f has completed successfully is the appearance of new text on the screen and a new buffer name in the mode line. If the specified file does not exist and could not be created, or cannot be read, then you get an error, with an error message displayed in the echo area.
If you visit a file that is already in Emacs, C-x C-f does not make another copy. It selects the existing buffer containing that file. However, before doing so, it checks that the file itself has not changed since you visited or saved it last. If the file has changed, a warning message is shown. See Simultaneous Editing.
If you try to visit a file larger than
large-file-warning-threshold (the default is 10000000, which is
about 10 megabytes), Emacs will ask you for confirmation first. You
can answer y to proceed with visiting the file. Note, however,
that Emacs cannot visit files that are larger than the maximum Emacs
buffer size, which is around 256 megabytes on 32-bit machines
(see Buffers). If you try, Emacs will display an error message
saying that the maximum buffer size has been exceeded.
On graphical terminals, there are two additional methods for visiting files. Firstly, when Emacs is built with a suitable GUI toolkit, commands invoked with the mouse (by clicking on the menu bar or tool bar) use the toolkit's standard File Selection dialog instead of prompting for the file name in the minibuffer. On Unix and GNU/Linux platforms, Emacs does that when built with GTK, LessTif, and Motif toolkits; on MS-Windows, the GUI version does that by default. For information on how to customize this, see Dialog Boxes.
Secondly, Emacs supports the “drag and drop” protocol on the X window system. Dropping a file into an ordinary Emacs window visits the file using that window. However, dropping a file into a window displaying a Dired buffer moves or copies the file into the displayed directory. For details, see Drag and Drop, Misc Dired Features.
What if you want to create a new file? Just visit it. Emacs displays ‘(New file)’ in the echo area, but in other respects behaves as if you had visited an existing empty file. If you make any changes and save them, the file is created.
Emacs recognizes from the contents of a file which convention it uses to separate lines—newline (used on GNU/Linux and on Unix), carriage-return linefeed (used on Microsoft systems), or just carriage-return (used on the Macintosh)—and automatically converts the contents to the normal Emacs convention, which is that the newline character separates lines. This is a part of the general feature of coding system conversion (see Coding Systems), and makes it possible to edit files imported from different operating systems with equal convenience. If you change the text and save the file, Emacs performs the inverse conversion, changing newlines back into carriage-return linefeed or just carriage-return if appropriate.
If the file you specify is actually a directory, C-x C-f invokes
Dired, the Emacs directory browser, so that you can “edit” the contents
of the directory (see Dired). Dired is a convenient way to view, delete,
or operate on the files in the directory. However, if the variable
find-file-run-dired is nil, then it is an error to try
to visit a directory.
Files which are actually collections of other files, or file archives, are visited in special modes which invoke a Dired-like environment to allow operations on archive members. See File Archives, for more about these features.
If the file name you specify contains shell-style wildcard
characters, Emacs visits all the files that match it. Wildcards
include ‘?’, ‘*’, and ‘[...]’ sequences. To enter
the wild card ‘?’ in a file name in the minibuffer, you need to
type C-q ?. See Quoted File Names, for information on how to
visit a file whose name actually contains wildcard characters. You
can disable the wildcard feature by customizing
find-file-wildcards.
If you visit a file that the operating system won't let you modify,
or that is marked read-only, Emacs makes the buffer read-only too, so
that you won't go ahead and make changes that you'll have trouble
saving afterward. You can make the buffer writable with C-x C-q
(toggle-read-only). See Misc Buffer.
If you want to visit a file as read-only in order to protect
yourself from entering changes accidentally, visit it with the command
C-x C-r (find-file-read-only) instead of C-x C-f.
If you visit a nonexistent file unintentionally (because you typed the
wrong file name), use the C-x C-v command
(find-alternate-file) to visit the file you really wanted.
C-x C-v is similar to C-x C-f, but it kills the current
buffer (after first offering to save it if it is modified). When
C-x C-v reads the file name to visit, it inserts the entire
default file name in the buffer, with point just after the directory
part; this is convenient if you made a slight error in typing the name.
If you find a file which exists but cannot be read, C-x C-f signals an error.
C-x 4 f (find-file-other-window) is like C-x C-f
except that the buffer containing the specified file is selected in another
window. The window that was selected before C-x 4 f continues to
show the same buffer it was already showing. If this command is used when
only one window is being displayed, that window is split in two, with one
window showing the same buffer as before, and the other one showing the
newly requested file. See Windows.
C-x 5 f (find-file-other-frame) is similar, but opens a
new frame, or makes visible any existing frame showing the file you
seek. This feature is available only when you are using a window
system. See Frames.
If you wish to edit a file as a sequence of ASCII characters with no special
encoding or conversion, use the M-x find-file-literally command.
It visits a file, like C-x C-f, but does not do format conversion
(see Formatted Text), character code conversion (see Coding Systems), or automatic uncompression (see Compressed Files), and
does not add a final newline because of require-final-newline.
If you already have visited the same file in the usual (non-literal)
manner, this command asks you whether to visit it literally instead.
Two special hook variables allow extensions to modify the operation of
visiting files. Visiting a file that does not exist runs the functions
in the list find-file-not-found-functions; this variable holds a list
of functions, and the functions are called one by one (with no
arguments) until one of them returns non-nil. This is not a
normal hook, and the name ends in ‘-functions’ rather than ‘-hook’
to indicate that fact.
Successful visiting of any file, whether existing or not, calls the
functions in the list find-file-hook, with no arguments.
This variable is a normal hook. In the case of a nonexistent file, the
find-file-not-found-functions are run first. See Hooks.
There are several ways to specify automatically the major mode for editing the file (see Choosing Modes), and to specify local variables defined for that file (see File Variables).
Saving a buffer in Emacs means writing its contents back into the file that was visited in the buffer.
These are the commands that relate to saving and writing files.
save-buffer).
save-some-buffers).
not-modified).
With prefix argument (C-u), mark the current buffer as changed.
write-file).
When you wish to save the file and make your changes permanent, type
C-x C-s (save-buffer). After saving is finished, C-x C-s
displays a message like this:
Wrote /u/rms/gnu/gnu.tasks
If the selected buffer is not modified (no changes have been made in it since the buffer was created or last saved), saving is not really done, because it would have no effect. Instead, C-x C-s displays a message like this in the echo area:
(No changes need to be saved)
The command C-x s (save-some-buffers) offers to save any
or all modified buffers. It asks you what to do with each buffer. The
possible responses are analogous to those of query-replace:
save-some-buffers without any more saving.
save-some-buffers without even asking
about other buffers.
save-some-buffers, which asks the
question again.
C-x C-c, the key sequence to exit Emacs, invokes
save-some-buffers and therefore asks the same questions.
If you have changed a buffer but you do not want to save the changes,
you should take some action to prevent it. Otherwise, each time you use
C-x s or C-x C-c, you are liable to save this buffer by
mistake. One thing you can do is type M-~ (not-modified),
which clears out the indication that the buffer is modified. If you do
this, none of the save commands will believe that the buffer needs to be
saved. (‘~’ is often used as a mathematical symbol for `not'; thus
M-~ is `not', metafied.) You could also use
set-visited-file-name (see below) to mark the buffer as visiting
a different file name, one which is not in use for anything important.
Alternatively, you can cancel all the changes made since the file was
visited or saved, by reading the text from the file again. This is
called reverting. See Reverting. You could also undo all the
changes by repeating the undo command C-x u until you have undone
all the changes; but reverting is easier.
M-x set-visited-file-name alters the name of the file that the
current buffer is visiting. It reads the new file name using the
minibuffer. Then it marks the buffer as visiting that file name, and
changes the buffer name correspondingly. set-visited-file-name
does not save the buffer in the newly visited file; it just alters the
records inside Emacs in case you do save later. It also marks the
buffer as “modified” so that C-x C-s in that buffer
will save.
If you wish to mark the buffer as visiting a different file and save it
right away, use C-x C-w (write-file). It is
equivalent to set-visited-file-name followed by C-x C-s
(except that C-x C-w asks for confirmation if the file exists).
C-x C-s used on a buffer that is not visiting a file has the
same effect as C-x C-w; that is, it reads a file name, marks the
buffer as visiting that file, and saves it there. The default file name in
a buffer that is not visiting a file is made by combining the buffer name
with the buffer's default directory (see File Names).
If the new file name implies a major mode, then C-x C-w switches
to that major mode, in most cases. The command
set-visited-file-name also does this. See Choosing Modes.
If Emacs is about to save a file and sees that the date of the latest version on disk does not match what Emacs last read or wrote, Emacs notifies you of this fact, because it probably indicates a problem caused by simultaneous editing and requires your immediate attention. See Simultaneous Editing.
On most operating systems, rewriting a file automatically destroys all record of what the file used to contain. Thus, saving a file from Emacs throws away the old contents of the file—or it would, except that Emacs carefully copies the old contents to another file, called the backup file, before actually saving.
For most files, the variable make-backup-files determines
whether to make backup files. On most operating systems, its default
value is t, so that Emacs does write backup files.
For files managed by a version control system (see Version Control), the variable vc-make-backup-files determines whether
to make backup files. By default it is nil, since backup files
are redundant when you store all the previous versions in a version
control system. See General VC Options.
The default value of the backup-enable-predicate variable
prevents backup files being written for files in the directories used
for temporary files, specified by temporary-file-directory or
small-temporary-file-directory.
At your option, Emacs can keep either a single backup file or a series of numbered backup files for each file that you edit.
Emacs makes a backup for a file only the first time the file is saved from one buffer. No matter how many times you save a file, its backup file continues to contain the contents from before the file was visited. Normally this means that the backup file contains the contents from before the current editing session; however, if you kill the buffer and then visit the file again, a new backup file will be made by the next save.
You can also explicitly request making another backup file from a buffer even though it has already been saved at least once. If you save the buffer with C-u C-x C-s, the version thus saved will be made into a backup file if you save the buffer again. C-u C-u C-x C-s saves the buffer, but first makes the previous file contents into a new backup file. C-u C-u C-u C-x C-s does both things: it makes a backup from the previous contents, and arranges to make another from the newly saved contents if you save again.
If you choose to have a single backup file (this is the default), the backup file's name is normally constructed by appending ‘~’ to the file name being edited; thus, the backup file for eval.c would be eval.c~.
You can change this behavior by defining the variable
make-backup-file-name-function to a suitable function.
Alternatively you can customize the variable
backup-directory-alist to specify that files matching certain
patterns should be backed up in specific directories.
A typical use is to add an element ("." . dir) to make
all backups in the directory with absolute name dir; Emacs
modifies the backup file names to avoid clashes between files with the
same names originating in different directories. Alternatively,
adding, say, ("." . ".~") would make backups in the invisible
subdirectory .~ of the original file's directory. Emacs
creates the directory, if necessary, to make the backup.
If access control stops Emacs from writing backup files under the usual names, it writes the backup file as %backup%~ in your home directory. Only one such file can exist, so only the most recently made such backup is available.
If you choose to have a series of numbered backup files, backup file
names contain ‘.~’, the number, and another ‘~’ after the
original file name. Thus, the backup files of eval.c would be
called eval.c.~1~, eval.c.~2~, and so on, all the way
through names like eval.c.~259~ and beyond. The variable
backup-directory-alist applies to numbered backups just as
usual.
The choice of single backup or numbered backups is controlled by the
variable version-control. Its possible values are
tnilneverYou can set version-control locally in an individual buffer to
control the making of backups for that buffer's file. For example,
Rmail mode locally sets version-control to never to make sure
that there is only one backup for an Rmail file. See Locals.
If you set the environment variable VERSION_CONTROL, to tell
various GNU utilities what to do with backup files, Emacs also obeys the
environment variable by setting the Lisp variable version-control
accordingly at startup. If the environment variable's value is ‘t’
or ‘numbered’, then version-control becomes t; if the
value is ‘nil’ or ‘existing’, then version-control
becomes nil; if it is ‘never’ or ‘simple’, then
version-control becomes never.
To prevent excessive consumption of disk space, Emacs can delete numbered backup versions automatically. Generally Emacs keeps the first few backups and the latest few backups, deleting any in between. This happens every time a new backup is made.
The two variables kept-old-versions and
kept-new-versions control this deletion. Their values are,
respectively, the number of oldest (lowest-numbered) backups to keep
and the number of newest (highest-numbered) ones to keep, each time a
new backup is made. The backups in the middle (excluding those oldest
and newest) are the excess middle versions—those backups are
deleted. These variables' values are used when it is time to delete
excess versions, just after a new backup version is made; the newly
made backup is included in the count in kept-new-versions. By
default, both variables are 2.
If delete-old-versions is t, Emacs deletes the excess
backup files silently. If it is nil, the default, Emacs asks
you whether it should delete the excess backup versions. If it has
any other value, then Emacs never automatically deletes backups.
Dired's . (Period) command can also be used to delete old versions. See Dired Deletion.
Backup files can be made by copying the old file or by renaming it. This makes a difference when the old file has multiple names (hard links). If the old file is renamed into the backup file, then the alternate names become names for the backup file. If the old file is copied instead, then the alternate names remain names for the file that you are editing, and the contents accessed by those names will be the new contents.
The method of making a backup file may also affect the file's owner and group. If copying is used, these do not change. If renaming is used, you become the file's owner, and the file's group becomes the default (different operating systems have different defaults for the group).
Having the owner change is usually a good idea, because then the owner
always shows who last edited the file. Also, the owners of the backups
show who produced those versions. Occasionally there is a file whose
owner should not change; it is a good idea for such files to contain
local variable lists to set backup-by-copying-when-mismatch
locally (see File Variables).
The choice of renaming or copying is controlled by four variables.
Renaming is the default choice. If the variable
backup-by-copying is non-nil, copying is used. Otherwise,
if the variable backup-by-copying-when-linked is non-nil,
then copying is used for files that have multiple names, but renaming
may still be used when the file being edited has only one name. If the
variable backup-by-copying-when-mismatch is non-nil, then
copying is used if renaming would cause the file's owner or group to
change. backup-by-copying-when-mismatch is t by default
if you start Emacs as the superuser. The fourth variable,
backup-by-copying-when-privileged-mismatch, gives the highest
numeric user-id for which backup-by-copying-when-mismatch will be
forced on. This is useful when low-numbered user-ids are assigned to
special system users, such as root, bin, daemon,
etc., which must maintain ownership of files.
When a file is managed with a version control system (see Version Control), Emacs does not normally make backups in the usual way for that file. But check-in and check-out are similar in some ways to making backups. One unfortunate similarity is that these operations typically break hard links, disconnecting the file name you visited from any alternate names for the same file. This has nothing to do with Emacs—the version control system does it.
If the value of the variable require-final-newline is
t, saving or writing a file silently puts a newline at the end
if there isn't already one there. If the value is visit, Emacs
adds a newline at the end of any file that doesn't have one, just
after it visits the file. (This marks the buffer as modified, and you
can undo it.) If the value is visit-save, that means to add
newlines both on visiting and on saving. If the value is nil,
Emacs leaves the end of the file unchanged; if it's neither nil
nor t, Emacs asks you whether to add a newline. The default is
nil.
Many major modes are designed for specific kinds of files that are
always supposed to end in newlines. These major modes set the
variable require-final-newline according to
mode-require-final-newline. By setting the latter variable,
you can control how these modes handle final newlines.
When Emacs saves a file, it invokes the fsync system call to
force the data immediately out to disk. This is important for safety
if the system crashes or in case of power outage. However, it can be
disruptive on laptops using power saving, because it requires the disk
to spin up each time you save a file. Setting
write-region-inhibit-fsync to a non-nil value disables
this synchronization. Be careful—this means increased risk of data
loss.
Simultaneous editing occurs when two users visit the same file, both make changes, and then both save them. If nobody were informed that this was happening, whichever user saved first would later find that his changes were lost.
On some systems, Emacs notices immediately when the second user starts to change the file, and issues an immediate warning. On all systems, Emacs checks when you save the file, and warns if you are about to overwrite another user's changes. You can prevent loss of the other user's work by taking the proper corrective action instead of saving the file.
When you make the first modification in an Emacs buffer that is visiting a file, Emacs records that the file is locked by you. (It does this by creating a symbolic link in the same directory with a different name.) Emacs removes the lock when you save the changes. The idea is that the file is locked whenever an Emacs buffer visiting it has unsaved changes.
If you begin to modify the buffer while the visited file is locked by
someone else, this constitutes a collision. When Emacs detects a
collision, it asks you what to do, by calling the Lisp function
ask-user-about-lock. You can redefine this function for the sake
of customization. The standard definition of this function asks you a
question and accepts three possible answers:
file-locked), and the buffer
contents remain unchanged—the modification you were trying to make
does not actually take place.
Note that locking works on the basis of a file name; if a file has multiple names, Emacs does not realize that the two names are the same file and cannot prevent two users from editing it simultaneously under different names. However, basing locking on names means that Emacs can interlock the editing of new files that will not really exist until they are saved.
Some systems are not configured to allow Emacs to make locks, and there are cases where lock files cannot be written. In these cases, Emacs cannot detect trouble in advance, but it still can detect the collision when you try to save a file and overwrite someone else's changes.
If Emacs or the operating system crashes, this may leave behind lock files which are stale, so you may occasionally get warnings about spurious collisions. When you determine that the collision is spurious, just use p to tell Emacs to go ahead anyway.
Every time Emacs saves a buffer, it first checks the last-modification date of the existing file on disk to verify that it has not changed since the file was last visited or saved. If the date does not match, it implies that changes were made in the file in some other way, and these changes are about to be lost if Emacs actually does save. To prevent this, Emacs displays a warning message and asks for confirmation before saving. Occasionally you will know why the file was changed and know that it does not matter; then you can answer yes and proceed. Otherwise, you should cancel the save with C-g and investigate the situation.
The first thing you should do when notified that simultaneous editing
has already taken place is to list the directory with C-u C-x C-d
(see Directories). This shows the file's current author. You
should attempt to contact him to warn him not to continue editing.
Often the next step is to save the contents of your Emacs buffer under a
different name, and use diff to compare the two files.
You can arrange to keep identical shadow copies of certain files in more than one place—possibly on different machines. To do this, first you must set up a shadow file group, which is a set of identically-named files shared between a list of sites. The file group is permanent and applies to further Emacs sessions as well as the current one. Once the group is set up, every time you exit Emacs, it will copy the file you edited to the other files in its group. You can also do the copying without exiting Emacs, by typing M-x shadow-copy-files.
To set up a shadow file group, use M-x shadow-define-literal-group or M-x shadow-define-regexp-group. See their documentation strings for further information.
Before copying a file to its shadows, Emacs asks for confirmation. You can answer “no” to bypass copying of this file, this time. If you want to cancel the shadowing permanently for a certain file, use M-x shadow-cancel to eliminate or change the shadow file group.
A shadow cluster is a group of hosts that share directories, so that copying to or from one of them is sufficient to update the file on all of them. Each shadow cluster has a name, and specifies the network address of a primary host (the one we copy files to), and a regular expression that matches the host names of all the other hosts in the cluster. You can define a shadow cluster with M-x shadow-define-cluster.
You can arrange to put a time stamp in a file, so that it will be updated automatically each time you edit and save the file. The time stamp has to be in the first eight lines of the file, and you should insert it like this:
Time-stamp: <>
or like this:
Time-stamp: " "
Then add the hook function time-stamp to the hook
before-save-hook; that hook function will automatically update
the time stamp, inserting the current date and time when you save the
file. You can also use the command M-x time-stamp to update the
time stamp manually. For other customizations, see the Custom group
time-stamp. Note that non-numeric fields in the time stamp are
formatted according to your locale setting (see Environment).
If you have made extensive changes to a file and then change your mind about them, you can get rid of them by reading in the previous version of the file. To do this, use M-x revert-buffer, which operates on the current buffer. Since reverting a buffer unintentionally could lose a lot of work, you must confirm this command with yes.
revert-buffer tries to position point in such a way that, if
the file was edited only slightly, you will be at approximately the
same piece of text after reverting as before. However, if you have made
drastic changes, point may wind up in a totally different piece of text.
Reverting marks the buffer as “not modified” until another change is made.
Some kinds of buffers whose contents reflect data bases other than files,
such as Dired buffers, can also be reverted. For them, reverting means
recalculating their contents from the appropriate data base. Buffers
created explicitly with C-x b cannot be reverted; revert-buffer
reports an error when asked to do so.
When you edit a file that changes automatically and frequently—for example, a log of output from a process that continues to run—it may be useful for Emacs to revert the file without querying you, whenever you visit the file again with C-x C-f.
To request this behavior, set the variable revert-without-query
to a list of regular expressions. When a file name matches one of these
regular expressions, find-file and revert-buffer will
revert it automatically if it has changed—provided the buffer itself
is not modified. (If you have edited the text, it would be wrong to
discard your changes.)
You may find it useful to have Emacs revert files automatically when they change. Three minor modes are available to do this.
M-x global-auto-revert-mode runs Global Auto-Revert mode, which periodically checks all file buffers and reverts when the corresponding file has changed. M-x auto-revert-mode runs a local version, Auto-Revert mode, which applies only to the buffer in which it was activated. Auto-Revert mode can be used to “tail” a file, such as a system log, so that changes made to that file by other programs are continuously displayed. To do this, just move the point to the end of the buffer, and it will stay there as the file contents change. However, if you are sure that the file will only change by growing at the end, you can tail the file more efficiently using Auto-Revert Tail mode, M-x auto-revert-tail-mode.
The variable auto-revert-interval controls how often to check
for a changed file. Since checking a remote file is too slow, these
modes do not check or revert remote files.
See VC Mode Line, for Auto Revert peculiarities in buffers that visit files under version control.
Emacs saves all the visited files from time to time (based on counting your keystrokes) without being asked. This is called auto-saving. It prevents you from losing more than a limited amount of work if the system crashes.
When Emacs determines that it is time for auto-saving, each buffer is considered, and is auto-saved if auto-saving is turned on for it and it has been changed since the last time it was auto-saved. The message ‘Auto-saving...’ is displayed in the echo area during auto-saving, if any files are actually auto-saved. Errors occurring during auto-saving are caught so that they do not interfere with the execution of commands you have been typing.
Auto-saving does not normally save in the files that you visited, because it can be very undesirable to save a program that is in an inconsistent state when you have made half of a planned change. Instead, auto-saving is done in a different file called the auto-save file, and the visited file is changed only when you request saving explicitly (such as with C-x C-s).
Normally, the auto-save file name is made by appending ‘#’ to the
front and rear of the visited file name. Thus, a buffer visiting file
foo.c is auto-saved in a file #foo.c#. Most buffers that
are not visiting files are auto-saved only if you request it explicitly;
when they are auto-saved, the auto-save file name is made by appending
‘#’ to the front and rear of buffer name, then
adding digits and letters at the end for uniqueness. For
example, the ‘*mail*’ buffer in which you compose messages to be
sent might be auto-saved in a file named #*mail*#704juu. Auto-save file
names are made this way unless you reprogram parts of Emacs to do
something different (the functions make-auto-save-file-name and
auto-save-file-name-p). The file name to be used for auto-saving
in a buffer is calculated when auto-saving is turned on in that buffer.
The variable auto-save-file-name-transforms allows a degree
of control over the auto-save file name. It lets you specify a series
of regular expressions and replacements to transform the auto save
file name. The default value puts the auto-save files for remote
files (see Remote Files) into the temporary file directory on the
local machine.
When you delete a substantial part of the text in a large buffer, auto save turns off temporarily in that buffer. This is because if you deleted the text unintentionally, you might find the auto-save file more useful if it contains the deleted text. To reenable auto-saving after this happens, save the buffer with C-x C-s, or use C-u 1 M-x auto-save-mode.
If you want auto-saving to be done in the visited file rather than
in a separate auto-save file, set the variable
auto-save-visited-file-name to a non-nil value. In this
mode, there is no real difference between auto-saving and explicit
saving.
A buffer's auto-save file is deleted when you save the buffer in its
visited file. To inhibit this, set the variable delete-auto-save-files
to nil. Changing the visited file name with C-x C-w or
set-visited-file-name renames any auto-save file to go with
the new visited name.
Each time you visit a file, auto-saving is turned on for that file's
buffer if the variable auto-save-default is non-nil (but not
in batch mode; see Entering Emacs). The default for this variable is
t, so auto-saving is the usual practice for file-visiting buffers.
Auto-saving can be turned on or off for any existing buffer with the
command M-x auto-save-mode. Like other minor mode commands, M-x
auto-save-mode turns auto-saving on with a positive argument, off with a
zero or negative argument; with no argument, it toggles.
Emacs does auto-saving periodically based on counting how many characters
you have typed since the last time auto-saving was done. The variable
auto-save-interval specifies how many characters there are between
auto-saves. By default, it is 300. Emacs doesn't accept values that are
too small: if you customize auto-save-interval to a value less
than 20, Emacs will behave as if the value is 20.
Auto-saving also takes place when you stop typing for a while. The
variable auto-save-timeout says how many seconds Emacs should
wait before it does an auto save (and perhaps also a garbage
collection). (The actual time period is longer if the current buffer is
long; this is a heuristic which aims to keep out of your way when you
are editing long buffers, in which auto-save takes an appreciable amount
of time.) Auto-saving during idle periods accomplishes two things:
first, it makes sure all your work is saved if you go away from the
terminal for a while; second, it may avoid some auto-saving while you
are actually typing.
Emacs also does auto-saving whenever it gets a fatal error. This includes killing the Emacs job with a shell command such as ‘kill %emacs’, or disconnecting a phone line or network connection.
You can request an auto-save explicitly with the command M-x do-auto-save.
You can use the contents of an auto-save file to recover from a loss of data with the command M-x recover-file <RET> file <RET>. This visits file and then (after your confirmation) restores the contents from its auto-save file #file#. You can then save with C-x C-s to put the recovered text into file itself. For example, to recover file foo.c from its auto-save file #foo.c#, do:
M-x recover-file <RET> foo.c <RET>
yes <RET>
C-x C-s
Before asking for confirmation, M-x recover-file displays a directory listing describing the specified file and the auto-save file, so you can compare their sizes and dates. If the auto-save file is older, M-x recover-file does not offer to read it.
If Emacs or the computer crashes, you can recover all the files you were editing from their auto save files with the command M-x recover-session. This first shows you a list of recorded interrupted sessions. Move point to the one you choose, and type C-c C-c.
Then recover-session asks about each of the files that were
being edited during that session, asking whether to recover that file.
If you answer y, it calls recover-file, which works in its
normal fashion. It shows the dates of the original file and its
auto-save file, and asks once again whether to recover that file.
When recover-session is done, the files you've chosen to
recover are present in Emacs buffers. You should then save them. Only
this—saving them—updates the files themselves.
Emacs records interrupted sessions for later recovery in files named
~/.emacs.d/auto-save-list/.saves-pid-hostname. All
of this name except pid-hostname comes from the
value of auto-save-list-file-prefix. You can record sessions
in a different place by customizing that variable. If you set
auto-save-list-file-prefix to nil in your .emacs
file, sessions are not recorded for recovery.
Symbolic links and hard links both make it possible for several file names to refer to the same file. Hard links are alternate names that refer directly to the file; all the names are equally valid, and no one of them is preferred. By contrast, a symbolic link is a kind of defined alias: when foo is a symbolic link to bar, you can use either name to refer to the file, but bar is the real name, while foo is just an alias. More complex cases occur when symbolic links point to directories.
If you visit two names for the same file, normally Emacs makes two different buffers, but it warns you about the situation.
Normally, if you visit a file which Emacs is already visiting under
a different name, Emacs displays a message in the echo area and uses
the existing buffer visiting that file. This can happen on systems
that support symbolic links, or if you use a long file name on a
system that truncates long file names. You can suppress the message by
setting the variable find-file-suppress-same-file-warnings to a
non-nil value. You can disable this feature entirely by setting
the variable find-file-existing-other-name to nil: then
if you visit the same file under two different names, you get a separate
buffer for each file name.
If the variable find-file-visit-truename is non-nil,
then the file name recorded for a buffer is the file's truename
(made by replacing all symbolic links with their target names), rather
than the name you specify. Setting find-file-visit-truename also
implies the effect of find-file-existing-other-name.
Version control systems are packages that can record multiple versions of a source file, usually storing the unchanged parts of the file just once. Version control systems also record history information such as the creation time of each version, who created it, and a description of what was changed in that version.
The Emacs version control interface is called VC. Its commands work with different version control systems—currently, it supports CVS, GNU Arch, RCS, Meta-CVS, Subversion, and SCCS. Of these, the GNU project distributes CVS, GNU Arch, and RCS; we recommend that you use either CVS or GNU Arch for your projects, and RCS for individual files. We also have free software to replace SCCS, known as CSSC; if you are using SCCS and don't want to make the incompatible change to RCS or CVS, you can switch to CSSC.
VC is enabled by default in Emacs. To disable it, set the
customizable variable vc-handled-backends to nil
(see Customizing VC).
VC allows you to use a version control system from within Emacs, integrating the version control operations smoothly with editing. VC provides a uniform interface to version control, so that regardless of which version control system is in use, you can use it the same way.
This section provides a general overview of version control, and describes the version control systems that VC supports. You can skip this section if you are already familiar with the version control system you want to use.
VC currently works with six different version control systems or “back ends”: CVS, GNU Arch, RCS, Meta-CVS, Subversion, and SCCS.
CVS is a free version control system that is used for the majority of free software projects today. It allows concurrent multi-user development either locally or over the network. Some of its shortcomings, corrected by newer systems such as GNU Arch, are that it lacks atomic commits or support for renaming files. VC supports all basic editing operations under CVS, but for some less common tasks you still need to call CVS from the command line. Note also that before using CVS you must set up a repository, which is a subject too complex to treat here.
GNU Arch is a new version control system that is designed for distributed work. It differs in many ways from old well-known systems, such as CVS and RCS. It supports different transports for interoperating between users, offline operations, and it has good branching and merging features. It also supports atomic commits, and history of file renaming and moving. VC does not support all operations provided by GNU Arch, so you must sometimes invoke it from the command line, or use a specialized module.
RCS is the free version control system around which VC was initially built. The VC commands are therefore conceptually closest to RCS. Almost everything you can do with RCS can be done through VC. You cannot use RCS over the network though, and it only works at the level of individual files, rather than projects. You should use it if you want a simple, yet reliable tool for handling individual files.
Subversion is a free version control system designed to be similar to CVS but without CVS's problems. Subversion supports atomic commits, and versions directories, symbolic links, meta-data, renames, copies, and deletes. It can be used via http or via its own protocol.
Meta-CVS is another attempt to solve problems arising in CVS. It supports directory structure versioning, improved branching and merging, and use of symbolic links and meta-data in repositories.
SCCS is a proprietary but widely used version control system. In terms of capabilities, it is the weakest of the six that VC supports. VC compensates for certain features missing in SCCS (snapshots, for example) by implementing them itself, but some other VC features, such as multiple branches, are not available with SCCS. You should use SCCS only if for some reason you cannot use RCS, or one of the higher-level systems such as CVS or GNU Arch.
In the following, we discuss mainly RCS, SCCS and CVS. Nearly everything said about CVS applies to GNU Arch, Subversion and Meta-CVS as well.
When a file is under version control, we also say that it is registered in the version control system. Each registered file has a corresponding master file which represents the file's present state plus its change history—enough to reconstruct the current version or any earlier version. Usually the master file also records a log entry for each version, describing in words what was changed in that version.
The file that is maintained under version control is sometimes called the work file corresponding to its master file. You edit the work file and make changes in it, as you would with an ordinary file. (With SCCS and RCS, you must lock the file before you start to edit it.) After you are done with a set of changes, you check the file in, which records the changes in the master file, along with a log entry for them.
With CVS, there are usually multiple work files corresponding to a single master file—often each user has his own copy. It is also possible to use RCS in this way, but this is not the usual way to use RCS.
A version control system typically has some mechanism to coordinate between users who want to change the same file. One method is locking (analogous to the locking that Emacs uses to detect simultaneous editing of a file, but distinct from it). The other method is to merge your changes with other people's changes when you check them in.
With version control locking, work files are normally read-only so that you cannot change them. You ask the version control system to make a work file writable for you by locking it; only one user can do this at any given time. When you check in your changes, that unlocks the file, making the work file read-only again. This allows other users to lock the file to make further changes. SCCS always uses locking, and RCS normally does.
The other alternative for RCS is to let each user modify the work file at any time. In this mode, locking is not required, but it is permitted; check-in is still the way to record a new version.
CVS normally allows each user to modify his own copy of the work file at any time, but requires merging with changes from other users at check-in time. However, CVS can also be set up to require locking. (see CVS Options).
Projects that use a revision control system can have two types of log for changes. One is the per-file log maintained by the revision control system: each time you check in a change, you must fill out a log entry for the change (see Log Buffer). This kind of log is called the version control log, also the revision control log, RCS log, or CVS log.
The other kind of log is the file ChangeLog (see Change Log). It provides a chronological record of all changes to a large portion of a program—typically one directory and its subdirectories. A small program would use one ChangeLog file; a large program may well merit a ChangeLog file in each major directory. See Change Log.
A project maintained with version control can use just the per-file log, or it can use both kinds of logs. It can handle some files one way and some files the other way. Each project has its policy, which you should follow.
When the policy is to use both, you typically want to write an entry for each change just once, then put it into both logs. You can write the entry in ChangeLog, then copy it to the log buffer when you check in the change. Or you can write the entry in the log buffer while checking in the change, and later use the C-x v a command to copy it to ChangeLog (see Change Logs and VC).
When you visit a file that is under version control, Emacs indicates this on the mode line. For example, ‘RCS-1.3’ says that RCS is used for that file, and the current version is 1.3.
The character between the back-end name and the version number indicates the version control status of the file. ‘-’ means that the work file is not locked (if locking is in use), or not modified (if locking is not in use). ‘:’ indicates that the file is locked, or that it is modified. If the file is locked by some other user (for instance, ‘jim’), that is displayed as ‘RCS:jim:1.3’.
When Auto Revert mode (see Reverting) reverts a buffer that is
under version control, it updates the version control information in
the mode line. However, Auto Revert mode may not properly update this
information if the version control status changes without changes to
the work file, from outside the current Emacs session. If you set
auto-revert-check-vc-info to t, Auto Revert mode updates
the version control status information every
auto-revert-interval seconds, even if the work file itself is
unchanged. The resulting CPU usage depends on the version control
system, but is usually not excessive.
The principal VC command is an all-purpose command that performs either locking or check-in, depending on the situation.
The precise action of this command depends on the state of the file, and whether the version control system uses locking or not. SCCS and RCS normally use locking; CVS normally does not use locking.
As a special convenience that is particularly useful for files with locking, you can let Emacs check a file in or out whenever you change its read-only flag. This means, for example, that you cannot accidentally edit a file without properly checking it out first. To achieve this, bind the key C-x C-q to vc-toggle-read-only in your ~/.emacs file. (See Init Rebinding.)
If locking is used for the file (as with SCCS, and RCS in its default mode), C-x v v can either lock a file or check it in:
These rules also apply when you use CVS in locking mode, except that there is no such thing as stealing a lock.
When there is no locking—the default for CVS—work files are always writable; you do not need to do anything before you begin to edit a file. The status indicator on the mode line is ‘-’ if the file is unmodified; it flips to ‘:’ as soon as you save any changes in the work file.
Here is what C-x v v does when using CVS:
These rules also apply when you use RCS in the mode that does not require locking, except that automatic merging of changes from the master file is not implemented. Unfortunately, this means that nothing informs you if another user has checked in changes in the same file since you began editing it, and when this happens, his changes will be effectively removed when you check in your version (though they will remain in the master file, so they will not be entirely lost). You must therefore verify that the current version is unchanged, before you check in your changes. We hope to eliminate this risk and provide automatic merging with RCS in a future Emacs version.
In addition, locking is possible with RCS even in this mode, although it is not required; C-x v v with an unmodified file locks the file, just as it does with RCS in its normal (locking) mode.
When you give a prefix argument to vc-next-action (C-u
C-x v v), it still performs the next logical version control
operation, but accepts additional arguments to specify precisely how
to do the operation.
When you check in changes, C-x v v first reads a log entry. It pops up a buffer called ‘*VC-Log*’ for you to enter the log entry.
Sometimes the ‘*VC-Log*’ buffer contains default text when you enter it, typically the last log message entered. If it does, mark and point are set around the entire contents of the buffer so that it is easy to kill the contents of the buffer with C-w.
If you work by writing entries in the ChangeLog (see Change Log) and then commit the change under revision control, you can generate the Log Edit text from the ChangeLog using C-c C-a (log-edit-insert-changelog). This looks for entries for the file(s) concerned in the top entry in the ChangeLog and uses those paragraphs as the log text. This text is only inserted if the top entry was made under your user name on the current date. See Change Logs and VC, for the opposite way of working—generating ChangeLog entries from the revision control log.
In the ‘*VC-Log*’ buffer, C-c C-f (M-x log-edit-show-files) shows the list of files to be committed in case you need to check that. (This can be a list of more than one file if you use VC Dired mode or PCL-CVS. See VC Dired Mode, and About PCL-CVS.)
When you have finished editing the log message, type C-c C-c to exit the buffer and commit the change.
To abort check-in, just don't type C-c C-c in that buffer. You can switch buffers and do other editing. As long as you don't try to check in another file, the entry you were editing remains in the ‘*VC-Log*’ buffer, and you can go back to that buffer at any time to complete the check-in.
If you change several source files for the same reason, it is often convenient to specify the same log entry for many of the files. To do this, use the history of previous log entries. The commands M-n, M-p, M-s and M-r for doing this work just like the minibuffer history commands (except that these versions are used outside the minibuffer).
Each time you check in a file, the log entry buffer is put into VC Log
mode, which involves running two hooks: text-mode-hook and
vc-log-mode-hook. See Hooks.
One of the convenient features of version control is the ability to examine any version of a file, or compare two versions.
To examine an old version in its entirety, visit the file and then type
C-x v ~ version <RET> (vc-version-other-window).
This puts the text of version version in a file named
filename.~version~, and visits it in its own buffer
in a separate window. (In RCS, you can also select an old version
and create a branch from it. See Branches.)
It is usually more convenient to compare two versions of the file,
with the command C-x v = (vc-diff). Plain C-x v =
compares the current buffer contents (saving them in the file if
necessary) with the last checked-in version of the file. C-u C-x
v =, with a numeric argument, reads a file name and two version
numbers, then compares those versions of the specified file. Both
forms display the output in a special buffer in another window.
You can specify a checked-in version by its number; an empty input specifies the current contents of the work file (which may be different from all the checked-in versions). You can also specify a snapshot name (see Snapshots) instead of one or both version numbers.
If you supply a directory name instead of the name of a registered file, this command compares the two specified versions of all registered files in that directory and its subdirectories.
C-x v = works by running a variant of the diff utility
designed to work with the version control system in use. When you
invoke diff this way, in addition to the options specified by
diff-switches (see Comparing Files), it receives those
specified by vc-diff-switches, plus those specified for the
specific back end by vc-backend-diff-switches. For
instance, when the version control back end is RCS, diff uses
the options in vc-rcs-diff-switches. The
‘vc...diff-switches’ variables are nil by default.
Unlike the M-x diff command, C-x v = does not try to locate the changes in the old and new versions. This is because normally one or both versions do not exist as files when you compare them; they exist only in the records of the master file. See Comparing Files, for more information about M-x diff.
For some backends, you can display the file annotated with per-line version information and using colors to enhance the visual appearance, with the command M-x vc-annotate. It creates a new buffer to display file's text, colored to show how old each part is. Text colored red is new, blue means old, and intermediate colors indicate intermediate ages. By default, the time scale is 360 days, so that everything more than one year old is shown in blue.
When you give a prefix argument to this command, it uses the minibuffer to read two arguments: which version number to display and annotate (instead of the current file contents), and a stretch factor for the time scale. A stretch factor of 0.1 means that the color range from red to blue spans the past 36 days instead of 360 days. A stretch factor greater than 1 means the color range spans more than a year.
From the annotate buffer, you can use the following keys to browse the annotations of past revisions, view diffs, or view log entries:
This section explains the secondary commands of VC; those that you might use once a day.
You can put any file under version control by simply visiting it, and
then typing C-x v i (vc-register).
To register the file, Emacs must choose which version control system
to use for it. If the file's directory already contains files
registered in a version control system, Emacs uses that system. If
there is more than one system in use for a directory, Emacs uses the one
that appears first in vc-handled-backends (see Customizing VC).
On the other hand, if there are no files already registered,
Emacs uses the first system from vc-handled-backends that could
register the file (for example, you cannot register a file under CVS if
its directory is not already part of a CVS tree); with the default
value of vc-handled-backends, this means that Emacs uses RCS in
this situation.
If locking is in use, C-x v i leaves the file unlocked and read-only. Type C-x v v if you wish to start editing it. After registering a file with CVS, you must subsequently commit the initial version by typing C-x v v. Until you do that, the version appears as ‘@@’ in the mode line.
The initial version number for a newly registered file is 1.1, by
default. You can specify a different default by setting the variable
vc-default-init-version, or you can give C-x v i a numeric
argument; then it reads the initial version number for this particular
file using the minibuffer.
If vc-initial-comment is non-nil, C-x v i reads an
initial comment to describe the purpose of this source file. Reading
the initial comment works like reading a log entry (see Log Buffer).
To view the detailed version control status and history of a file,
type C-x v l (vc-print-log). It displays the history of
changes to the current file, including the text of the log entries. The
output appears in a separate window. The point is centered at the
revision of the file that is currently being visited.
From the change log buffer, the following keys are used to move between the logs of revisions and files, to view past revisions, and to view diffs:
If you want to discard your current set of changes and revert to the
last version checked in, use C-x v u (vc-revert-buffer).
This leaves the file unlocked; if locking is in use, you must first lock
the file again before you change it again. C-x v u requires
confirmation, unless it sees that you haven't made any changes since the
last checked-in version.
C-x v u is also the command to unlock a file if you lock it and then decide not to change it.
To cancel a change that you already checked in, use C-x v c
(vc-cancel-version). This command discards all record of the
most recent checked-in version. C-x v c also offers to revert
your work file and buffer to the previous version (the one that precedes
the version that is deleted).
If you answer no, VC keeps your changes in the buffer, and locks the file. The no-revert option is useful when you have checked in a change and then discover a trivial error in it; you can cancel the erroneous check-in, fix the error, and check the file in again.
When C-x v c does not revert the buffer, it unexpands all version control headers in the buffer instead (see Version Headers). This is because the buffer no longer corresponds to any existing version. If you check it in again, the check-in process will expand the headers properly for the new version number.
However, it is impossible to unexpand the RCS ‘$Log$’ header automatically. If you use that header feature, you have to unexpand it by hand—by deleting the entry for the version that you just canceled.
Be careful when invoking C-x v c, as it is easy to lose a lot of work with it. To help you be careful, this command always requires confirmation with yes. Note also that this command is disabled under CVS, because canceling versions is very dangerous and discouraged with CVS.
The VC Dired Mode described here works with all the version control systems that VC supports. Another more powerful facility, designed specifically for CVS, is called PCL-CVS. See About PCL-CVS.
When you are working on a large program, it is often useful to find
out which files have changed within an entire directory tree, or to view
the status of all files under version control at once, and to perform
version control operations on collections of files. You can use the
command C-x v d (vc-directory) to make a directory listing
that includes only files relevant for version control.
C-x v d creates a buffer which uses VC Dired Mode. This looks
much like an ordinary Dired buffer (see Dired); however, normally it
shows only the noteworthy files (those locked or not up-to-date). This
is called terse display. If you set the variable
vc-dired-terse-display to nil, then VC Dired shows all
relevant files—those managed under version control, plus all
subdirectories (full display). The command v t in a VC
Dired buffer toggles between terse display and full display (see VC Dired Commands).
By default, VC Dired produces a recursive listing of noteworthy or
relevant files at or below the given directory. You can change this by
setting the variable vc-dired-recurse to nil; then VC
Dired shows only the files in the given directory.
The line for an individual file shows the version control state in the place of the hard link count, owner, group, and size of the file. If the file is unmodified, in sync with the master file, the version control state shown is blank. Otherwise it consists of text in parentheses. Under RCS and SCCS, the name of the user locking the file is shown; under CVS, an abbreviated version of the ‘cvs status’ output is used. Here is an example using RCS:
/home/jim/project:
-rw-r--r-- (jim) Apr 2 23:39 file1
-r--r--r-- Apr 5 20:21 file2
The files ‘file1’ and ‘file2’ are under version control, ‘file1’ is locked by user jim, and ‘file2’ is unlocked.
Here is an example using CVS:
/home/joe/develop:
-rw-r--r-- (modified) Aug 2 1997 file1.c
-rw-r--r-- Apr 4 20:09 file2.c
-rw-r--r-- (merge) Sep 13 1996 file3.c
Here ‘file1.c’ is modified with respect to the repository, and ‘file2.c’ is not. ‘file3.c’ is modified, but other changes have also been checked in to the repository—you need to merge them with the work file before you can check it in.
When VC Dired displays subdirectories (in the “full” display mode),
it omits some that should never contain any files under version control.
By default, this includes Version Control subdirectories such as
‘RCS’ and ‘CVS’; you can customize this by setting the
variable vc-directory-exclusion-list.
You can fine-tune VC Dired's format by typing C-u C-x v d—as in ordinary Dired, that allows you to specify additional switches for the ‘ls’ command.
All the usual Dired commands work normally in VC Dired mode, except
for v, which is redefined as the version control prefix. You can
invoke VC commands such as vc-diff and vc-print-log by
typing v =, or v l, and so on. Most of these commands apply
to the file name on the current line.
The command v v (vc-next-action) operates on all the
marked files, so that you can lock or check in several files at once.
If it operates on more than one file, it handles each file according to
its current state; thus, it might lock one file, but check in another
file. This could be confusing; it is up to you to avoid confusing
behavior by marking a set of files that are in a similar state. If no
files are marked, v v operates on the file in the current line.
If any files call for check-in, v v reads a single log entry, then uses it for all the files being checked in. This is convenient for registering or checking in several files at once, as part of the same change.
You can toggle between terse display (only locked files, or files not
up-to-date) and full display at any time by typing v t
(vc-dired-toggle-terse-mode). There is also a special command
* l (vc-dired-mark-locked), which marks all files currently
locked (or, with CVS, all files not up-to-date). Thus, typing * l
t k is another way to delete from the buffer all files except those
currently locked.
One use of version control is to maintain multiple “current” versions of a file. For example, you might have different versions of a program in which you are gradually adding various unfinished new features. Each such independent line of development is called a branch. VC allows you to create branches, switch between different branches, and merge changes from one branch to another. Please note, however, that branches are not supported for SCCS.
A file's main line of development is usually called the trunk. The versions on the trunk are normally numbered 1.1, 1.2, 1.3, etc. At any such version, you can start an independent branch. A branch starting at version 1.2 would have version number 1.2.1.1, and consecutive versions on this branch would have numbers 1.2.1.2, 1.2.1.3, 1.2.1.4, and so on. If there is a second branch also starting at version 1.2, it would consist of versions 1.2.2.1, 1.2.2.2, 1.2.2.3, etc.
If you omit the final component of a version number, that is called a branch number. It refers to the highest existing version on that branch—the head version of that branch. The branches in the example above have branch numbers 1.2.1 and 1.2.2.
To switch between branches, type C-u C-x v v and specify the version number you want to select. This version is then visited unlocked (write-protected), so you can examine it before locking it. Switching branches in this way is allowed only when the file is not locked.
You can omit the minor version number, thus giving only the branch number; this takes you to the head version on the chosen branch. If you only type <RET>, Emacs goes to the highest version on the trunk.
After you have switched to any branch (including the main branch), you stay on it for subsequent VC commands, until you explicitly select some other branch.
To create a new branch from a head version (one that is the latest in the branch that contains it), first select that version if necessary, lock it with C-x v v, and make whatever changes you want. Then, when you check in the changes, use C-u C-x v v. This lets you specify the version number for the new version. You should specify a suitable branch number for a branch starting at the current version. For example, if the current version is 2.5, the branch number should be 2.5.1, 2.5.2, and so on, depending on the number of existing branches at that point.
To create a new branch at an older version (one that is no longer the head of a branch), first select that version (see Switching Branches), then lock it with C-x v v. You'll be asked to confirm, when you lock the old version, that you really mean to create a new branch—if you say no, you'll be offered a chance to lock the latest version instead.
Then make your changes and type C-x v v again to check in a new version. This automatically creates a new branch starting from the selected version. You need not specially request a new branch, because that's the only way to add a new version at a point that is not the head of a branch.
After the branch is created, you “stay” on it. That means that subsequent check-ins create new versions on that branch. To leave the branch, you must explicitly select a different version with C-u C-x v v. To transfer changes from one branch to another, use the merge command, described in the next section.
When you have finished the changes on a certain branch, you will
often want to incorporate them into the file's main line of development
(the trunk). This is not a trivial operation, because development might
also have proceeded on the trunk, so that you must merge the
changes into a file that has already been changed otherwise. VC allows
you to do this (and other things) with the vc-merge command.
C-x v m (vc-merge) takes a set of changes and merges it
into the current version of the work file. It firsts asks you in the
minibuffer where the changes should come from. If you just type
<RET>, Emacs merges any changes that were made on the same branch
since you checked the file out (we call this merging the news).
This is the common way to pick up recent changes from the repository,
regardless of whether you have already changed the file yourself.
You can also enter a branch number or a pair of version numbers in the minibuffer. Then C-x v m finds the changes from that branch, or the differences between the two versions you specified, and merges them into the current version of the current file.
As an example, suppose that you have finished a certain feature on branch 1.3.1. In the meantime, development on the trunk has proceeded to version 1.5. To merge the changes from the branch to the trunk, first go to the head version of the trunk, by typing C-u C-x v v <RET>. Version 1.5 is now current. If locking is used for the file, type C-x v v to lock version 1.5 so that you can change it. Next, type C-x v m 1.3.1 <RET>. This takes the entire set of changes on branch 1.3.1 (relative to version 1.3, where the branch started, up to the last version on the branch) and merges it into the current version of the work file. You can now check in the changed file, thus creating version 1.6 containing the changes from the branch.
It is possible to do further editing after merging the branch, before the next check-in. But it is usually wiser to check in the merged version, then lock it and make the further changes. This will keep a better record of the history of changes.
When you merge changes into a file that has itself been modified, the changes might overlap. We call this situation a conflict, and reconciling the conflicting changes is called resolving a conflict.
Whenever conflicts occur during merging, VC detects them, tells you about them in the echo area, and asks whether you want help in merging. If you say yes, it starts an Ediff session (see Ediff).
If you say no, the conflicting changes are both inserted into the file, surrounded by conflict markers. The example below shows how a conflict region looks; the file is called ‘name’ and the current master file version with user B's changes in it is 1.11.
<<<<<<< name
User A's version
=======
User B's version
>>>>>>> 1.11
Then you can resolve the conflicts by editing the file manually. Or
you can type M-x vc-resolve-conflicts after visiting the file.
This starts an Ediff session, as described above. Don't forget to
check in the merged version afterwards.
It is often useful for multiple developers to work simultaneously on different branches of a file. CVS allows this by default; for RCS, it is possible if you create multiple source directories. Each source directory should have a link named RCS which points to a common directory of RCS master files. Then each source directory can have its own choice of selected versions, but all share the same common RCS records.
This technique works reliably and automatically, provided that the source files contain RCS version headers (see Version Headers). The headers enable Emacs to be sure, at all times, which version number is present in the work file.
If the files do not have version headers, you must instead tell Emacs explicitly in each session which branch you are working on. To do this, first find the file, then type C-u C-x v v and specify the correct branch number. This ensures that Emacs knows which branch it is using during this particular editing session.
A common way of using CVS is to set up a central CVS repository on some Internet host, then have each developer check out a personal working copy of the files on his local machine. Committing changes to the repository, and picking up changes from other users into one's own working area, then works by direct interactions with the CVS server.
One difficulty is that access to the CVS server is often slow, and that developers might need to work off-line as well. VC is designed to reduce the amount of network interaction necessary.
When VC sees that the CVS repository for a file is on a remote machine, it automatically makes local backups of unmodified versions of the file—automatic version backups. This means that you can compare the file to the repository version (C-x v =), or revert to that version (C-x v u), without any network interactions.
The local copy of the unmodified file is called a version backup to indicate that it corresponds exactly to a version that is stored in the repository. Note that version backups are not the same as ordinary Emacs backup files (see Backup). But they follow a similar naming convention.
For a file that comes from a remote CVS repository, VC makes a
version backup whenever you save the first changes to the file, and
removes it after you have committed your modified version to the
repository. You can disable the making of automatic version backups by
setting vc-cvs-stay-local to nil (see CVS Options).
The name of the automatic version backup for version version
of file file is file.~version.~. This is
almost the same as the name used by C-x v ~ (see Old Versions), the only difference being the additional dot (‘.’)
after the version number. This similarity is intentional, because
both kinds of files store the same kind of information. The file made
by C-x v ~ acts as a manual version backup.
All the VC commands that operate on old versions of a file can use both kinds of version backups. For instance, C-x v ~ uses either an automatic or a manual version backup, if possible, to get the contents of the version you request. Likewise, C-x v = and C-x v u use either an automatic or a manual version backup, if one of them exists, to get the contents of a version to compare or revert to. If you changed a file outside of Emacs, so that no automatic version backup was created for the previous text, you can create a manual backup of that version using C-x v ~, and thus obtain the benefit of the local copy for Emacs commands.
The only difference in Emacs's handling of manual and automatic version backups, once they exist, is that Emacs deletes automatic version backups when you commit to the repository. By contrast, manual version backups remain until you delete them.
When you make many changes to a file that comes from a remote repository, it can be convenient to have version control on your local machine as well. You can then record intermediate versions, revert to a previous state, etc., before you actually commit your changes to the remote server.
VC lets you do this by putting a file under a second, local version control system, so that the file is effectively registered in two systems at the same time. For the description here, we will assume that the remote system is CVS, and you use RCS locally, although the mechanism works with any combination of version control systems (back ends).
To make it work with other back ends, you must make sure that the
“more local” back end comes before the “more remote” back end in
the setting of vc-handled-backends (see Customizing VC). By
default, this variable is set up so that you can use remote CVS and
local RCS as described here.
To start using local RCS for a file that comes from a remote CVS
server, you must register the file in RCS, by typing C-u
C-x v v rcs <RET>. (In other words, use vc-next-action with a
prefix argument, and specify RCS as the back end.)
You can do this at any time; it does not matter whether you have already modified the file with respect to the version in the CVS repository. If possible, VC tries to make the RCS master start with the unmodified repository version, then checks in any local changes as a new version. This works if you have not made any changes yet, or if the unmodified repository version exists locally as a version backup (see Version Backups). If the unmodified version is not available locally, the RCS master starts with the modified version; the only drawback to this is that you cannot compare your changes locally to what is stored in the repository.
The version number of the RCS master is derived from the current CVS version, starting a branch from it. For example, if the current CVS version is 1.23, the local RCS branch will be 1.23.1. Version 1.23 in the RCS master will be identical to version 1.23 under CVS; your first changes are checked in as 1.23.1.1. (If the unmodified file is not available locally, VC will check in the modified file twice, both as 1.23 and 1.23.1.1, to make the revision numbers consistent.)
If you do not use locking under CVS (the default), locking is also disabled for RCS, so that editing under RCS works exactly as under CVS.
When you are done with local editing, you can commit the final version back to the CVS repository by typing C-u C-x v v cvs <RET>. This initializes the log entry buffer (see Log Buffer) to contain all the log entries you have recorded in the RCS master; you can edit them as you wish, and then commit in CVS by typing C-c C-c. If the commit is successful, VC removes the RCS master, so that the file is once again registered under CVS only. (The RCS master is not actually deleted, just renamed by appending ‘~’ to the name, so that you can refer to it later if you wish.)
While using local RCS, you can pick up recent changes from the CVS repository into your local file, or commit some of your changes back to CVS, without terminating local RCS version control. To do this, switch to the CVS back end temporarily, with the C-x v b command:
vc-switch-backend).
C-x v b does not change the buffer contents, or any files; it only changes VC's perspective on how to handle the file. Any subsequent VC commands for that file will operate on the back end that is currently selected.
If the current file is registered in more than one back end, typing C-x v b “cycles” through all of these back ends. With a prefix argument, it asks for the back end to use in the minibuffer.
Thus, if you are using local RCS, and you want to pick up some recent changes in the file from remote CVS, first visit the file, then type C-x v b to switch to CVS, and finally use C-x v m <RET> to merge the news (see Merging). You can then switch back to RCS by typing C-x v b again, and continue to edit locally.
But if you do this, the revision numbers in the RCS master no longer correspond to those of CVS. Technically, this is not a problem, but it can become difficult to keep track of what is in the CVS repository and what is not. So we suggest that you return from time to time to CVS-only operation, by committing your local changes back to the repository using C-u C-x v v cvs <RET>.
A snapshot is a named set of file versions (one for each registered file) that you can treat as a unit. One important kind of snapshot is a release, a (theoretically) stable version of the system that is ready for distribution to users.
There are two basic commands for snapshots; one makes a snapshot with a given name, the other retrieves a named snapshot.
C-x v s name <RET>vc-create-snapshot).
C-x v r name <RET>vc-retrieve-snapshot).
This command reports an error if any files are locked at or below the current directory, without changing anything; this is to avoid overwriting work in progress.
A snapshot uses a very small amount of resources—just enough to record the list of file names and which version belongs to the snapshot. Thus, you need not hesitate to create snapshots whenever they are useful.
You can give a snapshot name as an argument to C-x v = or C-x v ~ (see Old Versions). Thus, you can use it to compare a snapshot against the current files, or two snapshots against each other, or a snapshot against a named version.
VC's snapshot facilities are modeled on RCS's named-configuration support. They use RCS's native facilities for this, so under VC snapshots made using RCS are visible even when you bypass VC.
For SCCS, VC implements snapshots itself. The files it uses contain name/file/version-number triples. These snapshots are visible only through VC.
A snapshot is a set of checked-in versions. So make sure that all the files are checked in and not locked when you make a snapshot.
File renaming and deletion can create some difficulties with snapshots. This is not a VC-specific problem, but a general design issue in version control systems that no one has solved very well yet.
If you rename a registered file, you need to rename its master along
with it (the command vc-rename-file does this automatically). If
you are using SCCS, you must also update the records of the snapshot, to
mention the file by its new name (vc-rename-file does this,
too). An old snapshot that refers to a master file that no longer
exists under the recorded name is invalid; VC can no longer retrieve
it. It would be beyond the scope of this manual to explain enough about
RCS and SCCS to explain how to update the snapshots by hand.
Using vc-rename-file makes the snapshot remain valid for
retrieval, but it does not solve all problems. For example, some of the
files in your program probably refer to others by name. At the very
least, the makefile probably mentions the file that you renamed. If you
retrieve an old snapshot, the renamed file is retrieved under its new
name, which is not the name that the makefile expects. So the program
won't really work as retrieved.
This section explains the less-frequently-used features of VC.
If you use RCS or CVS for a program and also maintain a change log file for it (see Change Log), you can generate change log entries automatically from the version control log entries:
vc-update-change-log).
This command works with RCS or CVS only, not with SCCS.
For example, suppose the first line of ChangeLog is dated 1999-04-10, and that the only check-in since then was by Nathaniel Bowditch to rcs2log on 1999-05-22 with log text ‘Ignore log messages that start with `#'.’. Then C-x v a visits ChangeLog and inserts text like this:
1999-05-22 Nathaniel Bowditch <nat@apn.org>
* rcs2log: Ignore log messages that start with `#'.
You can then edit the new change log entry further as you wish.
Some of the new change log entries may duplicate what's already in ChangeLog. You will have to remove these duplicates by hand.
Normally, the log entry for file foo is displayed as ‘* foo: text of log entry’. The ‘:’ after foo is omitted if the text of the log entry starts with ‘(functionname): ’. For example, if the log entry for vc.el is ‘(vc-do-command): Check call-process status.’, then the text in ChangeLog looks like this:
1999-05-06 Nathaniel Bowditch <nat@apn.org>
* vc.el (vc-do-command): Check call-process status.
When C-x v a adds several change log entries at once, it groups related log entries together if they all are checked in by the same author at nearly the same time. If the log entries for several such files all have the same text, it coalesces them into a single entry. For example, suppose the most recent check-ins have the following log entries:
They appear like this in ChangeLog:
1999-04-01 Nathaniel Bowditch <nat@apn.org>
* vc.texinfo: Fix expansion typos.
* vc.el, vc-hooks.el: Don't call expand-file-name.
Normally, C-x v a separates log entries by a blank line, but you can mark several related log entries to be clumped together (without an intervening blank line) by starting the text of each related log entry with a label of the form ‘{clumpname} ’. The label itself is not copied to ChangeLog. For example, suppose the log entries are:
Then the text in ChangeLog looks like this:
1999-04-01 Nathaniel Bowditch <nat@apn.org>
* vc.texinfo: Fix expansion typos.
* vc.el, vc-hooks.el: Don't call expand-file-name.
A log entry whose text begins with ‘#’ is not copied to ChangeLog. For example, if you merely fix some misspellings in comments, you can log the change with an entry beginning with ‘#’ to avoid putting such trivia into ChangeLog.
When you rename a registered file, you must also rename its master
file correspondingly to get proper results. Use vc-rename-file
to rename the source file as you specify, and rename its master file
accordingly. It also updates any snapshots (see Snapshots) that
mention the file, so that they use the new name; despite this, the
snapshot thus modified may not completely work (see Snapshot Caveats).
Some backends do not provide an explicit rename operation to their
repositories. After issuing vc-rename-file, use C-x v v
on the original and renamed buffers and provide the necessary edit
log.
You cannot use vc-rename-file on a file that is locked by
someone else.
Sometimes it is convenient to put version identification strings directly into working files. Certain special strings called version headers are replaced in each successive version by the number of that version.
If you are using RCS, and version headers are present in your working files, Emacs can use them to determine the current version and the locking state of the files. This is more reliable than referring to the master files, which is done when there are no version headers. Note that in a multi-branch environment, version headers are necessary to make VC behave correctly (see Multi-User Branching).
Searching for version headers is controlled by the variable
vc-consult-headers. If it is non-nil (the default),
Emacs searches for headers to determine the version number you are
editing. Setting it to nil disables this feature.
You can use the C-x v h command (vc-insert-headers) to
insert a suitable header string.
The default header string is ‘$Id$’ for RCS and
‘%W%’ for SCCS. You can specify other headers to insert by
setting the variables vc-backend-header where
backend is rcs or sccs.
Instead of a single string, you can specify a list of strings; then each string in the list is inserted as a separate header on a line of its own.
It is often necessary to use “superfluous” backslashes when
writing the strings that you put in this variable. For instance, you
might write "$Id\$" rather than "$Id$". The extra
backslash prevents the string constant from being interpreted as a
header, if the Emacs Lisp file containing it is maintained with
version control.
Each header is inserted surrounded by tabs, inside comment delimiters,
on a new line at point. Normally the ordinary comment
start and comment end strings of the current mode are used, but for
certain modes, there are special comment delimiters for this purpose;
the variable vc-comment-alist specifies them. Each element of
this list has the form (mode starter ender).
The variable vc-static-header-alist specifies further strings
to add based on the name of the buffer. Its value should be a list of
elements of the form (regexp . format). Whenever
regexp matches the buffer name, format is inserted as part
of the header. A header line is inserted for each element that matches
the buffer name, and for each string specified by
vc-backend-header. The header line is made by processing the
string from vc-backend-header with the format taken from the
element. The default value for vc-static-header-alist is as follows:
(("\\.c$" .
"\n#ifndef lint\nstatic char vcid[] = \"\%s\";\n\
#endif /* lint */\n"))
It specifies insertion of text of this form:
#ifndef lint
static char vcid[] = "string";
#endif /* lint */
Note that the text above starts with a blank line.
If you use more than one version header in a file, put them close
together in the file. The mechanism in revert-buffer that
preserves markers may not handle markers positioned between two version
headers.
The variable vc-handled-backends determines which version
control systems VC should handle. The default value is (RCS CVS
SVN SCCS Arch MCVS), so it contains all six version systems that are
currently supported. If you want VC to ignore one or more of these
systems, exclude its name from the list. To disable VC entirely, set
this variable to nil.
The order of systems in the list is significant: when you visit a file
registered in more than one system (see Local Version Control),
VC uses the system that comes first in vc-handled-backends by
default. The order is also significant when you register a file for
the first time, see Registering for details.
Emacs normally does not save backup files for source files that are
maintained with version control. If you want to make backup files even
for files that use version control, set the variable
vc-make-backup-files to a non-nil value.
Normally the work file exists all the time, whether it is locked or
not. If you set vc-keep-workfiles to nil, then checking
in a new version with C-x v v deletes the work file; but any
attempt to visit the file with Emacs creates it again. (With CVS, work
files are always kept.)
Editing a version-controlled file through a symbolic link can be dangerous. It bypasses the version control system—you can edit the file without locking it, and fail to check your changes in. Also, your changes might overwrite those of another user. To protect against this, VC checks each symbolic link that you visit, to see if it points to a file under version control.
The variable vc-follow-symlinks controls what to do when a
symbolic link points to a version-controlled file. If it is nil,
VC only displays a warning message. If it is t, VC automatically
follows the link, and visits the real file instead, telling you about
this in the echo area. If the value is ask (the default), VC
asks you each time whether to follow the link.
If vc-suppress-confirm is non-nil, then C-x v v
and C-x v i can save the current buffer without asking, and
C-x v u also operates without asking for confirmation. (This
variable does not affect C-x v c; that operation is so drastic
that it should always ask for confirmation.)
VC mode does much of its work by running the shell commands for RCS,
CVS and SCCS. If vc-command-messages is non-nil, VC
displays messages to indicate which shell commands it runs, and
additional messages when the commands finish.
You can specify additional directories to search for version control
programs by setting the variable vc-path. These directories
are searched before the usual search path. It is rarely necessary to
set this variable, because VC normally finds the proper files
automatically.
By default, RCS uses locking to coordinate the activities of several
users, but there is a mode called non-strict locking in which
you can check-in changes without locking the file first. Use
‘rcs -U’ to switch to non-strict locking for a particular file,
see the rcs manual page for details.
When deducing the version control state of an RCS file, VC first looks for an RCS version header string in the file (see Version Headers). If there is no header string, VC normally looks at the file permissions of the work file; this is fast. But there might be situations when the file permissions cannot be trusted. In this case the master file has to be consulted, which is rather expensive. Also the master file can only tell you if there's any lock on the file, but not whether your work file really contains that locked version.
You can tell VC not to use version headers to determine the file
status by setting vc-consult-headers to nil. VC then
always uses the file permissions (if it is supposed to trust them), or
else checks the master file.
You can specify the criterion for whether to trust the file
permissions by setting the variable vc-mistrust-permissions.
Its value can be t (always mistrust the file permissions and
check the master file), nil (always trust the file
permissions), or a function of one argument which makes the decision.
The argument is the directory name of the RCS subdirectory. A
non-nil value from the function says to mistrust the file
permissions. If you find that the file permissions of work files are
changed erroneously, set vc-mistrust-permissions to t.
Then VC always checks the master file to determine the file's status.
VC determines the version control state of files under SCCS much as
with RCS. It does not consider SCCS version headers, though. Thus,
the variable vc-mistrust-permissions affects SCCS use, but
vc-consult-headers does not.
By default, CVS does not use locking to coordinate the activities of several users; anyone can change a work file at any time. However, there are ways to restrict this, resulting in behavior that resembles locking.
For one thing, you can set the CVSREAD environment variable (the value you use makes no difference). If this variable is defined, CVS makes your work files read-only by default. In Emacs, you must type C-x v v to make the file writable, so that editing works in fact similar as if locking was used. Note however, that no actual locking is performed, so several users can make their files writable at the same time. When setting CVSREAD for the first time, make sure to check out all your modules anew, so that the file protections are set correctly.
Another way to achieve something similar to locking is to use the
watch feature of CVS. If a file is being watched, CVS makes it
read-only by default, and you must also use C-x v v in Emacs to
make it writable. VC calls cvs edit to make the file writable,
and CVS takes care to notify other developers of the fact that you
intend to change the file. See the CVS documentation for details on
using the watch feature.
When a file's repository is on a remote machine, VC tries to keep
network interactions to a minimum. This is controlled by the variable
vc-cvs-stay-local. If it is t (the default), then VC uses
only the entry in the local CVS subdirectory to determine the file's
state (and possibly information returned by previous CVS commands). One
consequence of this is that when you have modified a file, and somebody
else has already checked in other changes to the file, you are not
notified of it until you actually try to commit. (But you can try to
pick up any recent changes from the repository first, using C-x v m
<RET>, see Merging).
The variable vc-cvs-global-switches, if non-nil,
should be a string specifying switches to pass to CVS for all CVS
operations.
When vc-cvs-stay-local is t, VC also makes local
version backups, so that simple diff and revert operations are
completely local (see Version Backups).
On the other hand, if you set vc-cvs-stay-local to nil,
then VC queries the remote repository before it decides what to
do in vc-next-action (C-x v v), just as it does for local
repositories. It also does not make any version backups.
You can also set vc-cvs-stay-local to a regular expression
that is matched against the repository host name; VC then stays local
only for repositories from hosts that match the pattern.
The file system groups files into directories. A directory listing is a list of all the files in a directory. Emacs provides commands to create and delete directories, and to make directory listings in brief format (file names only) and verbose format (sizes, dates, and authors included). There is also a directory browser called Dired; see Dired.
list-directory).
The command to display a directory listing is C-x C-d
(list-directory). It reads using the minibuffer a file name
which is either a directory to be listed or a wildcard-containing
pattern for the files to be listed. For example,
C-x C-d /u2/emacs/etc <RET>
lists all the files in directory /u2/emacs/etc. Here is an example of specifying a file name pattern:
C-x C-d /u2/emacs/src/*.c <RET>
Normally, C-x C-d displays a brief directory listing containing just file names. A numeric argument (regardless of value) tells it to make a verbose listing including sizes, dates, and owners (like ‘ls -l’).
The text of a directory listing is mostly obtained by running
ls in an inferior process. Two Emacs variables control the
switches passed to ls: list-directory-brief-switches is
a string giving the switches to use in brief listings ("-CF" by
default), and list-directory-verbose-switches is a string
giving the switches to use in a verbose listing ("-l" by
default).
Emacs adds information about the amount of free space on the disk
that contains the directory. To do this, it runs the program
specified by directory-free-space-program with arguments
directory-free-space-args.
The command M-x diff compares two files, displaying the
differences in an Emacs buffer named ‘*diff*’. It works by
running the diff program, using options taken from the variable
diff-switches. The value of diff-switches should be a
string; the default is "-c" to specify a context diff.
After running M-x diff, you can use C-x ` to visit
successive changed locations in the two source files, as in
Compilation mode (see Compilation Mode.) In the ‘*diff*’ buffer,
you can move to a particular hunk of changes and type C-c C-c
(diff-goto-source) to visit the corresponding source location.
The command M-x diff-backup compares a specified file with its most
recent backup. If you specify the name of a backup file,
diff-backup compares it with the source file that it is a backup
of.
The command M-x compare-windows compares the text in the current window with that in the next window. (For more information about windows in Emacs, Windows.) Comparison starts at point in each window, after pushing each initial point value on the mark ring in its respective buffer. Then it moves point forward in each window, one character at a time, until it reaches characters that don't match. Then the command exits.
If point in the two windows is followed by non-matching text when the command starts, it tries heuristically to advance up to matching text in the two windows, and then exits. So if you use M-x compare-windows repeatedly, each time it either skips one matching range or finds the start of another.
With a numeric argument, compare-windows ignores changes in
whitespace. If the variable compare-ignore-case is
non-nil, the comparison ignores differences in case as well.
If the variable compare-ignore-whitespace is non-nil,
compare-windows normally ignores changes in whitespace, and a
prefix argument turns that off.
Differences between versions of files are often distributed as patches, which are the output from diff or a version control system that uses diff. M-x diff-mode turns on Diff mode, a major mode for viewing and editing patches, either as “unified diffs” or “context diffs.”
You can use M-x smerge-mode to turn on Smerge mode, a minor mode for editing output from the diff3 program. This is typically the result of a failed merge from a version control system “update” outside VC, due to conflicting changes to a file. Smerge mode provides commands to resolve conflicts by selecting specific changes.
See also Emerge, and Top, for convenient facilities for merging two similar files.
Emacs has commands for performing many other operations on files. All operate on one file; they do not accept wildcard file names.
M-x view-file allows you to scan or read a file by sequential
screenfuls. It reads a file name argument using the minibuffer. After
reading the file into an Emacs buffer, view-file displays the
beginning. You can then type <SPC> to scroll forward one windowful,
or <DEL> to scroll backward. Various other commands are provided
for moving around in the file, but none for changing it; type ?
while viewing for a list of them. They are mostly the same as normal
Emacs cursor motion commands. To exit from viewing, type q.
The commands for viewing are defined by a special minor mode called View
mode.
A related command, M-x view-buffer, views a buffer already present in Emacs. See Misc Buffer.
M-x insert-file (also C-x i) inserts a copy of the contents of the specified file into the current buffer at point, leaving point unchanged before the contents and the mark after them.
M-x write-region is the inverse of M-x insert-file; it
copies the contents of the region into the specified file. M-x
append-to-file adds the text of the region to the end of the
specified file. See Accumulating Text. The variable
write-region-inhibit-fsync applies to these commands, as well
as saving files; see Customize Save.
M-x delete-file deletes the specified file, like the rm
command in the shell. If you are deleting many files in one directory, it
may be more convenient to use Dired (see Dired).
M-x rename-file reads two file names old and new using the minibuffer, then renames file old as new. If the file name new already exists, you must confirm with yes or renaming is not done; this is because renaming causes the old meaning of the name new to be lost. If old and new are on different file systems, the file old is copied and deleted.
If the argument new is just a directory name, the real new name is in that directory, with the same non-directory component as old. For example, M-x rename-file RET ~/foo RET /tmp RET renames ~/foo to /tmp/foo. The same rule applies to all the remaining commands in this section. All of them ask for confirmation when the new file name already exists, too.
The similar command M-x add-name-to-file is used to add an additional name to an existing file without removing its old name. The new name is created as a “hard link” to the existing file. The new name must belong on the same file system that the file is on. On MS-Windows, this command works only if the file resides in an NTFS file system. On MS-DOS, it works by copying the file.
M-x copy-file reads the file old and writes a new file named new with the same contents.
M-x make-symbolic-link reads two file names target and linkname, then creates a symbolic link named linkname, which points at target. The effect is that future attempts to open file linkname will refer to whatever file is named target at the time the opening is done, or will get an error if the name target is nonexistent at that time. This command does not expand the argument target, so that it allows you to specify a relative name as the target of the link.
Not all systems support symbolic links; on systems that don't support them, this command is not defined.
Emacs automatically uncompresses compressed files when you visit
them, and automatically recompresses them if you alter them and save
them. Emacs recognizes compressed files by their file names. File
names ending in ‘.gz’ indicate a file compressed with
gzip. Other endings indicate other compression programs.
Automatic uncompression and compression apply to all the operations in which Emacs uses the contents of a file. This includes visiting it, saving it, inserting its contents into a buffer, loading it, and byte compiling it.
To disable this feature, type the command M-x
auto-compression-mode. You can disenable it permanently by
customizing the variable auto-compression-mode.
A file whose name ends in ‘.tar’ is normally an archive
made by the tar program. Emacs views these files in a special
mode called Tar mode which provides a Dired-like list of the contents
(see Dired). You can move around through the list just as you
would in Dired, and visit the subfiles contained in the archive.
However, not all Dired commands are available in Tar mode.
If you enable Auto Compression mode (see Compressed Files), then
Tar mode is used also for compressed archives—files with extensions
‘.tgz’, .tar.Z and .tar.gz.
The keys e, f and <RET> all extract a component file into its own buffer. You can edit it there and when you save the buffer the edited version will replace the version in the Tar buffer. v extracts a file into a buffer in View mode. o extracts the file and displays it in another window, so you could edit the file and operate on the archive simultaneously. d marks a file for deletion when you later use x, and u unmarks a file, as in Dired. C copies a file from the archive to disk and R renames a file. g reverts the buffer from the archive on disk.
The keys M, G, and O change the file's permission bits, group, and owner, respectively.
If your display supports colors and the mouse, moving the mouse pointer across a file name highlights that file name, indicating that you can click on it. Clicking Mouse-2 on the highlighted file name extracts the file into a buffer and displays that buffer.
Saving the Tar buffer writes a new version of the archive to disk with the changes you made to the components.
You don't need the tar program to use Tar mode—Emacs reads
the archives directly. However, accessing compressed archives
requires the appropriate uncompression program.
A separate but similar Archive mode is used for archives produced by
the programs arc, jar, lzh, zip, and
zoo, which have extensions corresponding to the program names.
The key bindings of Archive mode are similar to those in Tar mode, with the addition of the m key which marks a file for subsequent operations, and M-<DEL> which unmarks all the marked files. Also, the a key toggles the display of detailed file information, for those archive types where it won't fit in a single line. Operations such as renaming a subfile, or changing its mode or owner, are supported only for some of the archive formats.
Unlike Tar mode, Archive mode runs the archiving program to unpack and repack archives. Details of the program names and their options can be set in the ‘Archive’ Customize group. However, you don't need these programs to look at the archive table of contents, only to extract or manipulate the subfiles in the archive.
You can refer to files on other machines using a special file name syntax:
/host:filename
/user@host:filename
/user@host#port:filename
/method:user@host:filename
/method:user@host#port:filename
To carry out this request, Emacs uses either the FTP program or a remote-login program such as ssh, rlogin, or telnet. You can always specify in the file name which method to use—for example, /ftp:user@host:filename uses FTP, whereas /ssh:user@host:filename uses ssh. When you don't specify a method in the file name, Emacs chooses the method as follows:
Remote file access through FTP is handled by the Ange-FTP package, which is documented in the following. Remote file access through the other methods is handled by the Tramp package, which has its own manual. See The Tramp Manual.
When the Ange-FTP package is used, Emacs logs in through FTP using your user name or the name user. It may ask you for a password from time to time; this is used for logging in on host. The form using port allows you to access servers running on a non-default TCP port.
If you want to disable backups for remote files, set the variable
ange-ftp-make-backup-files to nil.
By default, the auto-save files (see Auto Save Files) for remote
files are made in the temporary file directory on the local machine.
This is achieved using the variable auto-save-file-name-transforms.
Normally, if you do not specify a user name in a remote file name,
that means to use your own user name. But if you set the variable
ange-ftp-default-user to a string, that string is used instead.
(The Emacs package that implements FTP file access is called
ange-ftp.)
To visit files accessible by anonymous FTP, you use special user
names ‘anonymous’ or ‘ftp’. Passwords for these user names
are handled specially. The variable
ange-ftp-generate-anonymous-password controls what happens: if
the value of this variable is a string, then that string is used as
the password; if non-nil (the default), then the value of
user-mail-address is used; if nil, the user is prompted
for a password as normal.
Sometimes you may be unable to access files on a remote machine
because a firewall in between blocks the connection for security
reasons. If you can log in on a gateway machine from which the
target files are accessible, and whose FTP server supports
gatewaying features, you can still use remote file names; all you have
to do is specify the name of the gateway machine by setting the
variable ange-ftp-gateway-host, and set
ange-ftp-smart-gateway to t. Otherwise you may be able
to make remote file names work, but the procedure is complex. You can
read the instructions by typing M-x finder-commentary <RET>
ange-ftp <RET>.
You can entirely turn off the FTP file name feature by removing the
entries ange-ftp-completion-hook-function and
ange-ftp-hook-function from the variable
file-name-handler-alist. You can turn off the feature in
individual cases by quoting the file name with ‘/:’ (see Quoted File Names).
You can quote an absolute file name to prevent special characters and syntax in it from having their special effects. The way to do this is to add ‘/:’ at the beginning.
For example, you can quote a local file name which appears remote, to prevent it from being treated as a remote file name. Thus, if you have a directory named /foo: and a file named bar in it, you can refer to that file in Emacs as ‘/:/foo:/bar’.
‘/:’ can also prevent ‘~’ from being treated as a special character for a user's home directory. For example, /:/tmp/~hack refers to a file whose name is ~hack in directory /tmp.
Quoting with ‘/:’ is also a way to enter in the minibuffer a file name that contains ‘$’. In order for this to work, the ‘/:’ must be at the beginning of the minibuffer contents. (You can also double each ‘$’; see File Names with $.)
You can also quote wildcard characters with ‘/:’, for visiting. For example, /:/tmp/foo*bar visits the file /tmp/foo*bar.
Another method of getting the same result is to enter /tmp/foo[*]bar, which is a wildcard specification that matches only /tmp/foo*bar. However, in many cases there is no need to quote the wildcard characters because even unquoted they give the right result. For example, if the only file name in /tmp that starts with ‘foo’ and ends with ‘bar’ is foo*bar, then specifying /tmp/foo*bar will visit only /tmp/foo*bar.
You can use the file name cache to make it easy to locate a
file by name, without having to remember exactly where it is located.
When typing a file name in the minibuffer, C-<tab>
(file-cache-minibuffer-complete) completes it using the file
name cache. If you repeat C-<tab>, that cycles through the
possible completions of what you had originally typed. Note that the
C-<tab> character cannot be typed on most text-only
terminals.
The file name cache does not fill up automatically. Instead, you load file names into the cache using these commands:
load-path or exec-path, whose value is a list
of directory names.
In this section, we introduce some convenient facilities for finding recently-opened files, reading file names from a buffer, and viewing image files.
If you enable Recentf mode, with M-x recentf-mode, the
‘File’ menu includes a submenu containing a list of recently
opened files. M-x recentf-save-list saves the current
recent-file-list to a file, and M-x recentf-edit-list
edits it.
The M-x ffap command generalizes find-file with more
powerful heuristic defaults (see FFAP), often based on the text at
point. Partial Completion mode offers other features extending
find-file, which can be used with ffap.
See Completion Options.
Visiting image files automatically selects Image mode. This major
mode allows you to toggle between displaying the file as an image in
the Emacs buffer, and displaying its underlying text representation,
using the command C-c C-c (image-toggle-display). This
works only when Emacs can display the specific image type.
Thumbs mode is a major mode for viewing directories containing many image files. To use it, type M-x thumbs and specify the directory to view. The images in that directory will be displayed in a ‘Thumbs’ buffer as thumbnails; type RET on a thumbnail to view the full-size image. Thumbs mode requires the convert program, which is part of the ImageMagick software package.
If you regularly edit a certain group of files, you can define them
as a fileset. This lets you perform certain operations, such as
visiting, query-replace, and shell commands on all the files
at once. To make use of filesets, you must first add the expression
(filesets-init) to your .emacs file (see Init File).
This adds a ‘Filesets’ menu to the menu bar.
The simplest way to define filesets is by adding files to them one at a time. To add a file to fileset name, visit the file and type M-x filesets-add-buffer RET name RET. If there is no fileset name, this creates a new one, which initially creates only the current file. The command M-x filesets-remove-buffer removes the current file from a fileset.
You can also edit the list of filesets directly, with M-x filesets-edit (or by choosing ‘Edit Filesets’ from the ‘Filesets’ menu). The editing is performed in a Customize buffer (see Easy Customization). Filesets need not be a simple list of files—you can also define filesets using regular expression matching file names. Some examples of these more complicated filesets are shown in the Customize buffer. Remember to select ‘Save for future sessions’ if you want to use the same filesets in future Emacs sessions.
You can use the command M-x filesets-open to visit all the files in a fileset, and M-x filesets-close to close them. Use M-x filesets-run-cmd to run a shell command on all the files in a fileset. These commands are also available from the ‘Filesets’ menu, where each existing fileset is represented by a submenu.
The text you are editing in Emacs resides in an object called a buffer. Each time you visit a file, a buffer is created to hold the file's text. Each time you invoke Dired, a buffer is created to hold the directory listing. If you send a message with C-x m, a buffer named ‘*mail*’ is used to hold the text of the message. When you ask for a command's documentation, that appears in a buffer called ‘*Help*’.
At any time, one and only one buffer is current. It is also called the selected buffer. Often we say that a command operates on “the buffer” as if there were only one; but really this means that the command operates on the current buffer (most commands do).
When Emacs has multiple windows, each window has its own chosen buffer and displays it; at any time, only one of the windows is selected, and its chosen buffer is the current buffer. Each window's mode line normally displays the name of the window's chosen buffer (see Windows).
Each buffer has a name, which can be of any length, and you can select any buffer by giving its name. Most buffers are made by visiting files, and their names are derived from the files' names. But you can also create an empty buffer with any name you want. A newly started Emacs has a buffer named ‘*scratch*’ which can be used for evaluating Lisp expressions in Emacs. The distinction between upper and lower case matters in buffer names.
Each buffer records individually what file it is visiting, whether it is modified, and what major mode and minor modes are in effect in it (see Major Modes). Any Emacs variable can be made local to a particular buffer, meaning its value in that buffer can be different from the value in other buffers. See Locals.
A buffer's size cannot be larger than some maximum, which is defined by the largest buffer position representable by the Emacs integer data type. This is because Emacs tracks buffer positions using that data type. For 32-bit machines, the largest buffer size is 256 megabytes.
switch-to-buffer).
switch-to-buffer-other-window).
switch-to-buffer-other-frame).
To select the buffer named bufname, type C-x b bufname
<RET>. This runs the command switch-to-buffer with argument
bufname. You can use completion on an abbreviation for the buffer
name you want (see Completion). An empty argument to C-x b
specifies the buffer that was current most recently among those not
now displayed in any window.
For conveniently switching between a few buffers, use the commands
C-x <LEFT> and C-x <RIGHT>. C-x <RIGHT>
(previous-buffer) selects the previous buffer (following the order
of most recent selection in the current frame), while C-x <LEFT>
(next-buffer) moves through buffers in the reverse direction.
To select a buffer in a window other than the current one, type
C-x 4 b bufname <RET>. This runs the command
switch-to-buffer-other-window which displays the buffer
bufname in another window. By default, if displaying the buffer
causes two vertically adjacent windows to be displayed, the heights of
those windows are evened out; to countermand that and preserve the
window configuration, set the variable even-window-heights to
nil.
Similarly, C-x 5 b buffer <RET> runs the command
switch-to-buffer-other-frame which selects a buffer in another
frame.
You can control how certain buffers are handled by these commands by
customizing the variables special-display-buffer-names,
special-display-regexps, same-window-buffer-names, and
same-window-regexps. See Force Same Window, and
Special Buffer Frames, for more about these variables. In
addition, if the value of display-buffer-reuse-frames is
non-nil, and the buffer you want to switch to is already
displayed in some frame, Emacs will raise that frame.
Most buffers are created by visiting files, or by Emacs commands that
want to display some text, but you can also create a buffer explicitly
by typing C-x b bufname <RET>. This makes a new, empty
buffer that is not visiting any file, and selects it for editing. Such
buffers are used for making notes to yourself. If you try to save one,
you are asked for the file name to use. The new buffer's major mode is
determined by the value of default-major-mode (see Major Modes).
Note that C-x C-f, and any other command for visiting a file, can also be used to switch to an existing file-visiting buffer. See Visiting.
C-u M-g M-g, that is goto-line with a prefix argument
of just C-u, reads a number n using the minibuffer,
selects the most recently selected buffer other than the current
buffer in another window, and then moves point to the beginning of
line number n in that buffer. This is mainly useful in a buffer
that refers to line numbers in another buffer: if point is on or just
after a number, goto-line uses that number as the default for
n. Note that prefix arguments other than just C-u behave
differently. C-u 4 M-g M-g goes to line 4 in the current
buffer, without reading a number from the minibuffer. (Remember that
M-g M-g without prefix argument reads a number n and then
moves to line number n in the current buffer.)
Emacs uses buffer names that start with a space for internal purposes. It treats these buffers specially in minor ways—for example, by default they do not record undo information. It is best to avoid using such buffer names yourself.
list-buffers).
To display a list of existing buffers, type C-x C-b. Each line in the list shows one buffer's name, major mode and visited file. The buffers are listed in the order that they were current; the buffers that were current most recently come first.
‘*’ in the first field of a line indicates the buffer is “modified.” If several buffers are modified, it may be time to save some with C-x s (see Save Commands). ‘%’ indicates a read-only buffer. ‘.’ marks the current buffer. Here is an example of a buffer list:
CRM Buffer Size Mode File
. * .emacs 3294 Emacs-Lisp ~/.emacs
% *Help* 101 Help
search.c 86055 C ~/cvs/emacs/src/search.c
% src 20959 Dired by name ~/cvs/emacs/src/
* *mail* 42 Mail
% HELLO 1607 Fundamental ~/cvs/emacs/etc/HELLO
% NEWS 481184 Outline ~/cvs/emacs/etc/NEWS
*scratch* 191 Lisp Interaction
* *Messages* 1554 Fundamental
Note that the buffer ‘*Help*’ was made by a help request; it is
not visiting any file. The buffer src was made by Dired on the
directory ~/cvs/emacs/src/. You can list only buffers that are
visiting files by giving the command a prefix; for instance, by typing
C-u C-x C-b.
list-buffers omits buffers whose names begin with a space,
unless they visit files: such buffers are used internally by Emacs.
toggle-read-only).
A buffer can be read-only, which means that commands to change its contents are not allowed. The mode line indicates read-only buffers with ‘%%’ or ‘%*’ near the left margin. Read-only buffers are usually made by subsystems such as Dired and Rmail that have special commands to operate on the text; also by visiting a file whose access control says you cannot write it.
If you wish to make changes in a read-only buffer, use the command
C-x C-q (toggle-read-only). It makes a read-only buffer
writable, and makes a writable buffer read-only. This
works by setting the variable buffer-read-only, which has a local
value in each buffer and makes the buffer read-only if its value is
non-nil. If you have files under version control, you may find
it convenient to bind C-x C-q to vc-toggle-read-only
instead. Then, typing C-x C-q not only changes the read-only
flag, but it also checks the file in or out. See Version Control.
M-x rename-buffer changes the name of the current buffer. Specify the new name as a minibuffer argument. There is no default. If you specify a name that is in use for some other buffer, an error happens and no renaming is done.
M-x rename-uniquely renames the current buffer to a similar name with a numeric suffix added to make it both different and unique. This command does not need an argument. It is useful for creating multiple shell buffers: if you rename the ‘*shell*’ buffer, then do M-x shell again, it makes a new shell buffer named ‘*shell*’; meanwhile, the old shell buffer continues to exist under its new name. This method is also good for mail buffers, compilation buffers, and most Emacs features that create special buffers with particular names. (With some of these features, such as M-x compile, M-x grep an M-x info, you need to switch to some other buffer before using the command, in order for it to make a different buffer.)
M-x view-buffer is much like M-x view-file (see Misc File Ops) except that it examines an already existing Emacs buffer. View mode provides commands for scrolling through the buffer conveniently but not for changing it. When you exit View mode with q, that switches back to the buffer (and the position) which was previously displayed in the window. Alternatively, if you exit View mode with e, the buffer and the value of point that resulted from your perusal remain in effect.
The commands M-x append-to-buffer and M-x insert-buffer can be used to copy text from one buffer to another. See Accumulating Text.
If you continue an Emacs session for a while, you may accumulate a large number of buffers. You may then find it convenient to kill the buffers you no longer need. On most operating systems, killing a buffer releases its space back to the operating system so that other programs can use it. Here are some commands for killing buffers:
kill-buffer).
C-x k (kill-buffer) kills one buffer, whose name you
specify in the minibuffer. The default, used if you type just
<RET> in the minibuffer, is to kill the current buffer. If you
kill the current buffer, another buffer becomes current: one that was
current in the recent past but is not displayed in any window now. If
you ask to kill a file-visiting buffer that is modified (has unsaved
editing), then you must confirm with yes before the buffer is
killed.
The command M-x kill-some-buffers asks about each buffer, one by
one. An answer of y means to kill the buffer. Killing the current
buffer or a buffer containing unsaved changes selects a new buffer or asks
for confirmation just like kill-buffer.
The buffer menu feature (see Several Buffers) is also convenient for killing various buffers.
If you want to do something special every time a buffer is killed, you
can add hook functions to the hook kill-buffer-hook (see Hooks).
If you run one Emacs session for a period of days, as many people do, it can fill up with buffers that you used several days ago. The command M-x clean-buffer-list is a convenient way to purge them; it kills all the unmodified buffers that you have not used for a long time. An ordinary buffer is killed if it has not been displayed for three days; however, you can specify certain buffers that should never be killed automatically, and others that should be killed if they have been unused for a mere hour.
You can also have this buffer purging done for you, every day at
midnight, by enabling Midnight mode. Midnight mode operates each day at
midnight; at that time, it runs clean-buffer-list, or whichever
functions you have placed in the normal hook midnight-hook
(see Hooks).
To enable Midnight mode, use the Customization buffer to set the
variable midnight-mode to t. See Easy Customization.
The buffer-menu facility is like a “Dired for buffers”; it allows you to request operations on various Emacs buffers by editing an Emacs buffer containing a list of them. You can save buffers, kill them (here called deleting them, for consistency with Dired), or display them.
The command buffer-menu writes a list of all Emacs
buffers2 into the
buffer ‘*Buffer List*’, and selects that buffer in Buffer Menu
mode.
The buffer is read-only, and can be changed only through the special commands described in this section. The usual Emacs cursor motion commands can be used in the ‘*Buffer List*’ buffer. The following commands apply to the buffer described on the current line.
The d, C-d, s and u commands to add or remove flags also move down (or up) one line. They accept a numeric argument as a repeat count.
These commands operate immediately on the buffer listed on the current line:
There are also commands to select another buffer or buffers:
There is also a command that affects the entire buffer list:
What buffer-menu actually does is create and switch to a
suitable buffer, and turn on Buffer Menu mode in it. Everything else
described above is implemented by the special commands provided in
Buffer Menu mode. One consequence of this is that you can switch from
the ‘*Buffer List*’ buffer to another Emacs buffer, and edit
there. You can reselect the ‘*Buffer List*’ buffer later, to
perform the operations already requested, or you can kill it, or pay
no further attention to it.
The list in the ‘*Buffer List*’ buffer looks exactly like the
buffer list described in List Buffers, because they really are
the same. The only difference between buffer-menu and
list-buffers is that buffer-menu switches to the
‘*Buffer List*’ buffer in the selected window;
list-buffers displays the same buffer in another window. If
you run list-buffers (that is, type C-x C-b) and select
the buffer list manually, you can use all of the commands described
here.
Normally, the buffer ‘*Buffer List*’ is not updated automatically when
buffers are created and killed; its contents are just text. If you have
created, deleted or renamed buffers, the way to update ‘*Buffer
List*’ to show what you have done is to type g
(revert-buffer) or repeat the buffer-menu command.
The ‘*Buffer List*’ buffer does automatically update every
auto-revert-interval seconds if you enable Auto Revert mode in
it. (As long as it is not marked modified.) Global Auto Revert mode
does not update the ‘*Buffer List*’ buffer by default, but it
does if global-auto-revert-non-file-buffers is non-nil.
see Autorevert, for details.
The command buffer-menu-other-window works the same as
buffer-menu, except that it displays the buffers list in
another window.
An indirect buffer shares the text of some other buffer, which is called the base buffer of the indirect buffer. In some ways it is the analogue, for buffers, of a symbolic link between files.
clone-indirect-buffer-other-window).
The text of the indirect buffer is always identical to the text of its base buffer; changes made by editing either one are visible immediately in the other. But in all other respects, the indirect buffer and its base buffer are completely separate. They have different names, different values of point, different narrowing, different markers, different major modes, and different local variables.
An indirect buffer cannot visit a file, but its base buffer can. If you try to save the indirect buffer, that actually works by saving the base buffer. Killing the base buffer effectively kills the indirect buffer, but killing an indirect buffer has no effect on its base buffer.
One way to use indirect buffers is to display multiple views of an outline. See Outline Views.
A quick and handy way to make an indirect buffer is with the command
M-x clone-indirect-buffer. It creates and selects an indirect
buffer whose base buffer is the current buffer. With a numeric
argument, it prompts for the name of the indirect buffer; otherwise it
uses the name of the current buffer, with a ‘<n>’ suffix
added. C-x 4 c (clone-indirect-buffer-other-window)
works like M-x clone-indirect-buffer, but it selects the new
buffer in another window.
The more general way to make an indirect buffer is with the command M-x make-indirect-buffer. It creates an indirect buffer from buffer base-buffer, under the name indirect-name. It prompts for both base-buffer and indirect-name using the minibuffer.
This section describes several modes and features that make it more convenient to switch between buffers.
When several buffers visit identically-named files, Emacs must give the buffers distinct names. The usual method for making buffer names unique adds ‘<2>’, ‘<3>’, etc. to the end of the buffer names (all but one of them).
Other methods work by adding parts of each file's directory to the
buffer name. To select one, customize the variable
uniquify-buffer-name-style (see Easy Customization).
For instance, the forward naming method puts part of the
directory name at the beginning of the buffer name; using this method,
buffers visiting /u/mernst/tmp/Makefile and
/usr/projects/zaphod/Makefile would be named
‘tmp/Makefile’ and ‘zaphod/Makefile’, respectively (instead
of ‘Makefile’ and ‘Makefile<2>’).
By contrast, the post-forward naming method would call the
buffers ‘Makefile|tmp’ and ‘Makefile|zaphod’, and the
reverse naming method would call them ‘Makefile\tmp’ and
‘Makefile\zaphod’. The nontrivial difference between
post-forward and reverse occurs when just one directory
name is not enough to distinguish two files; then reverse puts
the directory names in reverse order, so that /top/middle/file
becomes ‘file\middle\top’, while post-forward puts them in
forward order after the file name, as in ‘file|top/middle’.
Which rule to follow for putting the directory names in the buffer name is not very important if you are going to look at the buffer names before you type one. But as an experienced user, if you know the rule, you won't have to look. And then you may find that one rule or another is easier for you to remember and utilize fast.
Iswitchb global minor mode provides convenient switching between buffers using substrings of their names. It replaces the normal definitions of C-x b, C-x 4 b, C-x 5 b, and C-x 4 C-o with alternative commands that are somewhat “smarter.”
When one of these commands prompts you for a buffer name, you can type in just a substring of the name you want to choose. As you enter the substring, Iswitchb mode continuously displays a list of buffers that match the substring you have typed.
At any time, you can type <RET> to select the first buffer in the list. So the way to select a particular buffer is to make it the first in the list. There are two ways to do this. You can type more of the buffer name and thus narrow down the list, excluding unwanted buffers above the desired one. Alternatively, you can use C-s and C-r to rotate the list until the desired buffer is first.
<TAB> while entering the buffer name performs completion on the string you have entered, based on the displayed list of buffers.
To enable Iswitchb mode, type M-x iswitchb-mode, or customize
the variable iswitchb-mode to t (see Easy Customization).
M-x bs-show pops up a buffer list similar to the one normally
displayed by C-x C-b but which you can customize. If you prefer
this to the usual buffer list, you can bind this command to C-x
C-b. To customize this buffer list, use the bs Custom group
(see Easy Customization).
MSB global minor mode (“MSB” stands for “mouse select buffer”)
provides a different and customizable mouse buffer menu which you may
prefer. It replaces the bindings of mouse-buffer-menu,
normally on C-Down-Mouse-1, and the menu bar buffer menu. You
can customize the menu in the msb Custom group.
Emacs can split a frame into two or many windows. Multiple windows can display parts of different buffers, or different parts of one buffer. Multiple frames always imply multiple windows, because each frame has its own set of windows. Each window belongs to one and only one frame.
Each Emacs window displays one Emacs buffer at any time. A single buffer may appear in more than one window; if it does, any changes in its text are displayed in all the windows where it appears. But the windows showing the same buffer can show different parts of it, because each window has its own value of point.
At any time, one of the windows is the selected window; the buffer this window is displaying is the current buffer. The terminal's cursor shows the location of point in this window. Each other window has a location of point as well. On text-only terminals, there is no way to show where those locations are, since the terminal has only one cursor. If you are using a window system, the location of point in a non-selected window is indicated by a hollow box. The cursor in the selected window is blinking or solid.
Commands to move point affect the value of point for the selected Emacs
window only. They do not change the value of point in any other Emacs
window, even one showing the same buffer. The same is true for commands
such as C-x b to change the current buffer in the selected window;
they do not affect other windows at all. However, there are other commands
such as C-x 4 b that select a different window and switch buffers in
it. Also, all commands that display information in a window, including
(for example) C-h f (describe-function) and C-x C-b
(list-buffers), work by switching buffers in a nonselected window
without affecting the selected window.
When multiple windows show the same buffer, they can have different regions, because they can have different values of point. However, they all have the same value for the mark, because each buffer has only one mark position.
Each window has its own mode line, which displays the buffer name, modification status and major and minor modes of the buffer that is displayed in the window. The selected window's mode line appears in a different color. See Mode Line, for full details on the mode line.
split-window-vertically).
split-window-horizontally).
The command C-x 2 (split-window-vertically) breaks the
selected window into two windows, one above the other. Both windows start
out displaying the same buffer, with the same value of point. By default
the two windows each get half the height of the window that was split; a
numeric argument specifies how many lines to give to the top window.
C-x 3 (split-window-horizontally) breaks the selected
window into two side-by-side windows. A numeric argument specifies how
many columns to give the one on the left. If you are not using
scrollbars, a vertical line separates the two windows.
You can customize its color with the face vertical-border.
Windows that are not the full width of the screen have mode lines, but
they are truncated. On terminals where Emacs does not support
highlighting, truncated mode lines sometimes do not appear in inverse
video.
You can split a window horizontally or vertically by clicking C-Mouse-2 in the mode line or the scroll bar. The line of splitting goes through the place where you click: if you click on the mode line, the new scroll bar goes above the spot; if you click in the scroll bar, the mode line of the split window is side by side with your click.
When a window is less than the full width, text lines too long to
fit are frequent. Continuing all those lines might be confusing, so
if the variable truncate-partial-width-windows is
non-nil, that forces truncation in all windows less than the
full width of the screen, independent of the buffer being displayed
and its value for truncate-lines. See Display Custom.
Horizontal scrolling is often used in side-by-side windows. See Horizontal Scrolling.
If split-window-keep-point is non-nil, the default,
both of the windows resulting from C-x 2 inherit the value of
point from the window that was split. This means that scrolling is
inevitable. If this variable is nil, then C-x 2 tries to
avoid scrolling the text currently visible on the screen, by putting
point in each window at a position already visible in the window. It
also selects whichever window contains the screen line that the cursor
was previously on. Some users prefer the latter mode on slow
terminals.
other-window). That is o, not zero.
scroll-other-window).
mouse-select-window).
To select a different window, click with Mouse-1 on its mode
line. With the keyboard, you can switch windows by typing C-x o
(other-window). That is an o, for “other,” not a zero.
When there are more than two windows, this command moves through all the
windows in a cyclic order, generally top to bottom and left to right.
After the rightmost and bottommost window, it goes back to the one at
the upper left corner. A numeric argument means to move several steps
in the cyclic order of windows. A negative argument moves around the
cycle in the opposite order. When the minibuffer is active, the
minibuffer is the last window in the cycle; you can switch from the
minibuffer window to one of the other windows, and later switch back and
finish supplying the minibuffer argument that is requested.
See Minibuffer Edit.
The usual scrolling commands (see Display) apply to the selected
window only, but there is one command to scroll the next window.
C-M-v (scroll-other-window) scrolls the window that
C-x o would select. It takes arguments, positive and negative,
like C-v. (In the minibuffer, C-M-v scrolls the window
that contains the minibuffer help display, if any, rather than the
next window in the standard cyclic order.)
The command M-x compare-windows lets you compare two files or buffers visible in two windows, by moving through them to the next mismatch. See Comparing Files, for details.
If you set mouse-autoselect-window to a non-nil value,
moving the mouse into a different window selects that window. This
feature is off by default.
C-x 4 is a prefix key for commands that select another window (splitting the window if there is only one) and select a buffer in that window. Different C-x 4 commands have different ways of finding the buffer to select.
switch-to-buffer-other-window.
display-buffer.
find-file-other-window. See Visiting.
dired-other-window. See Dired.
mail-other-window; its same-window analogue is C-x m
(see Sending Mail).
find-tag-other-window, the multiple-window variant of M-.
(see Tags).
find-file-read-only-other-window.
See Visiting.
Certain Emacs commands switch to a specific buffer with special contents. For example, M-x shell switches to a buffer named ‘*shell*’. By convention, all these commands are written to pop up the buffer in a separate window. But you can specify that certain of these buffers should appear in the selected window.
If you add a buffer name to the list same-window-buffer-names,
the effect is that such commands display that particular buffer by
switching to it in the selected window. For example, if you add the
element "*grep*" to the list, the grep command will
display its output buffer in the selected window.
The default value of same-window-buffer-names is not
nil: it specifies buffer names ‘*info*’, ‘*mail*’ and
‘*shell*’ (as well as others used by more obscure Emacs packages).
This is why M-x shell normally switches to the ‘*shell*’
buffer in the selected window. If you delete this element from the
value of same-window-buffer-names, the behavior of M-x
shell will change—it will pop up the buffer in another window
instead.
You can specify these buffers more generally with the variable
same-window-regexps. Set it to a list of regular expressions;
then any buffer whose name matches one of those regular expressions is
displayed by switching to it in the selected window. (Once again, this
applies only to buffers that normally get displayed for you in a
separate window.) The default value of this variable specifies Telnet
and rlogin buffers.
An analogous feature lets you specify buffers which should be displayed in their own individual frames. See Special Buffer Frames.
delete-window). The last character
in this key sequence is a zero.
delete-other-windows).
kill-buffer-and-window). The last character in this key
sequence is a zero.
enlarge-window).
enlarge-window-horizontally).
shrink-window-horizontally).
shrink-window-if-larger-than-buffer).
balance-windows).
mouse-delete-other-windows).
mouse-delete-window), unless the frame has only one window, in
which case it buries the current buffer instead and switches to another
buffer.
To delete a window, type C-x 0 (delete-window). (That is
a zero.) The space occupied by the deleted window is given to an
adjacent window (but not the minibuffer window, even if that is active
at the time). Once a window is deleted, its attributes are forgotten;
only restoring a window configuration can bring it back. Deleting the
window has no effect on the buffer it used to display; the buffer
continues to exist, and you can select it in any window with C-x
b.
C-x 4 0 (kill-buffer-and-window) is a stronger command
than C-x 0; it kills the current buffer and then deletes the
selected window.
C-x 1 (delete-other-windows) is more powerful in a
different way; it deletes all the windows except the selected one (and
the minibuffer); the selected window expands to use the whole frame
except for the echo area.
You can also delete a window by clicking on its mode line with Mouse-3, and delete all the windows in a frame except one window by clicking on that window's mode line with Mouse-2.
You can also adjust window heights and widths with the mouse. If you press Mouse-1 on a mode line, you can drag that mode line up or down, changing the heights of the windows above and below it. If you press it on the divider between two consecutive mode lines, you can drag that divider right or left, changing the widths of the windows to either side. Note that changing heights and widths with the mouse never deletes windows, it just refuses to make any window smaller than it can be.
To readjust the division of space among vertically adjacent windows,
use C-x ^ (enlarge-window). It makes the currently
selected window get one line bigger, or as many lines as is specified
with a numeric argument. With a negative argument, it makes the
selected window smaller. C-x }
(enlarge-window-horizontally) makes the selected window wider by
the specified number of columns. C-x {
(shrink-window-horizontally) makes the selected window narrower
by the specified number of columns.
When you make a window bigger, the space comes from one of its
neighbors. If this makes any window too small, it is deleted and its
space is given to an adjacent window. The minimum size is specified by
the variables window-min-height and window-min-width.
The command C-x - (shrink-window-if-larger-than-buffer)
reduces the height of the selected window, if it is taller than
necessary to show the whole text of the buffer it is displaying. It
gives the extra lines to other windows in the frame.
You can also use C-x + (balance-windows) to even out the
heights of all the windows in the selected frame.
M-x winner-mode is a global minor mode that records the
changes in the window configuration (i.e. how the frames are
partitioned into windows), so that you can “undo” them. To undo,
use C-c left (winner-undo). If you change your mind
while undoing, you can redo the changes you had undone using C-c
right (M-x winner-redo). Another way to enable Winner mode is
by customizing the variable winner-mode.
The Windmove commands move directionally between neighboring windows in a frame. M-x windmove-right selects the window immediately to the right of the currently selected one, and similarly for the “left,” “up,” and “down” counterparts. M-x windmove-default-keybindings binds these commands to S-right etc. (Not all terminals support shifted arrow keys, however.)
Follow minor mode (M-x follow-mode) synchronizes several windows on the same buffer so that they always display adjacent sections of that buffer. See Follow Mode.
M-x scroll-all-mode provides commands to scroll all visible
windows together. You can also turn it on by customizing the variable
scroll-all-mode. The commands provided are M-x
scroll-all-scroll-down-all, M-x scroll-all-page-down-all and
their corresponding “up” equivalents. To make this mode useful,
you should bind these commands to appropriate keys.
When using the X Window System, you can create multiple windows at the X level in a single Emacs session. Each X window that belongs to Emacs displays a frame which can contain one or several Emacs windows. A frame initially contains a single general-purpose Emacs window which you can subdivide vertically or horizontally into smaller windows. A frame normally contains its own echo area and minibuffer, but you can make frames that don't have these—they use the echo area and minibuffer of another frame.
Editing you do in one frame also affects the other frames. For instance, if you put text in the kill ring in one frame, you can yank it in another frame. If you exit Emacs through C-x C-c in one frame, it terminates all the frames. To delete just one frame, use C-x 5 0 (that is zero, not o).
To avoid confusion, we reserve the word “window” for the subdivisions that Emacs implements, and never use it to refer to a frame.
Emacs compiled for MS-DOS emulates some aspects of the window system so that you can use many of the features described in this chapter. See MS-DOS Mouse, for more information.
The mouse commands for selecting and copying a region are mostly
compatible with the xterm program. You can use the same mouse
commands for copying between Emacs and other window-based programs.
Most of these commands also work in Emacs when you run it under an
xterm terminal.
If you select a region with any of these mouse commands, and then immediately afterward type the <DELETE> function key, it deletes the region that you selected. The <BACKSPACE> function key and the ASCII character <DEL> do not do this; if you type any other key in between the mouse command and <DELETE>, it does not do this.
mouse-set-point).
This is normally the left button.
Normally, Emacs does not distinguish between ordinary mouse clicks and
clicks that select a frame. When you click on a frame to select it,
that also changes the selected window and cursor position according to
the mouse click position. On the X window system, you can change this
behavior by setting the variable
x-mouse-click-focus-ignore-position to t. Then the
first click selects the frame, but does not affect the selected window
or cursor position. If you click again in the same place, since that
click will be in the selected frame, it will change the window or
cursor position.
mouse-set-region). You can specify both ends of the
region with this single command.
If you move the mouse off the top or bottom of the window while
dragging, the window scrolls at a steady rate until you move the mouse
back into the window. This way, you can select regions that don't fit
entirely on the screen. The number of lines scrolled per step depends
on how far away from the window edge the mouse has gone; the variable
mouse-scroll-min-lines specifies a minimum step size.
If the variable mouse-drag-copy-region is nil, this
mouse command does not copy the selected region into the kill ring.
mouse-yank-at-click).
This is normally the middle button.
mouse-save-then-kill, has several functions
depending on where you click and the status of the region.
The most basic case is when you click Mouse-1 in one place and then Mouse-3 in another. This selects the text between those two positions as the region. It also copies the new region to the kill ring, so that you can copy it to someplace else.
If you click Mouse-1 in the text, scroll with the scroll bar, and then click Mouse-3, it remembers where point was before scrolling (where you put it with Mouse-1), and uses that position as the other end of the region. This is so that you can select a region that doesn't fit entirely on the screen.
More generally, if you do not have a highlighted region, Mouse-3 selects the text between point and the click position as the region. It does this by setting the mark where point was, and moving point to where you click.
If you have a highlighted region, or if the region was set just before by dragging button 1, Mouse-3 adjusts the nearer end of the region by moving it to where you click. The adjusted region's text also replaces the old region's text in the kill ring.
If you originally specified the region using a double or triple Mouse-1, so that the region is defined to consist of entire words or lines, then adjusting the region with Mouse-3 also proceeds by entire words or lines.
If you use Mouse-3 a second time consecutively, at the same place,
that kills the region already selected.
If you click on a character with open-parenthesis or close-parenthesis
syntax, it sets the region around the parenthetical grouping
which that character starts or ends. If you click on a character with
string-delimiter syntax (such as a singlequote or doublequote in C), it
sets the region around the string constant (using heuristics to figure
out whether that character is the beginning or the end of it).
The simplest way to kill text with the mouse is to press Mouse-1 at one end, then press Mouse-3 twice at the other end. See Killing. To copy the text into the kill ring without deleting it from the buffer, press Mouse-3 just once—or just drag across the text with Mouse-1. Then you can copy it elsewhere by yanking it.
To yank the killed or copied text somewhere else, move the mouse there
and press Mouse-2. See Yanking. However, if
mouse-yank-at-point is non-nil, Mouse-2 yanks at
point. Then it does not matter where you click, or even which of the
frame's windows you click on. The default value is nil. This
variable also affects yanking the secondary selection.
To copy text to another X window, kill it or save it in the kill ring. Under X, this also sets the primary selection. Then use the “paste” or “yank” command of the program operating the other window to insert the text from the selection.
To copy text from another X window, use the “cut” or “copy” command of the program operating the other window, to select the text you want. Then yank it in Emacs with C-y or Mouse-2.
The standard coding system for X selections is
compound-text-with-extensions. To specify another coding
system for X selections, use C-x <RET> x or C-x
<RET> X. See Specify Coding.
When Emacs puts text into the kill ring, or rotates text to the front
of the kill ring, it sets the primary selection in the X server.
This is how other X clients can access the text. Emacs also stores the
text in the cut buffer, but only if the text is short enough
(the value of x-cut-buffer-max specifies the maximum number of
characters); putting long strings in the cut buffer can be slow.
The commands to yank the first entry in the kill ring actually check first for a primary selection in another program; after that, they check for text in the cut buffer. If neither of those sources provides text to yank, the kill ring contents are used.
The secondary selection is another way of selecting text using X. It does not use point or the mark, so you can use it to kill text without setting point or the mark.
mouse-set-secondary). The highlighting appears and changes as
you drag. You can control the appearance of the highlighting by
customizing the secondary-selection face (see Face Customization).
If you move the mouse off the top or bottom of the window while dragging, the window scrolls at a steady rate until you move the mouse back into the window. This way, you can mark regions that don't fit entirely on the screen.
This way of setting the secondary selection does not alter the kill ring.
mouse-start-secondary).
mouse-secondary-save-then-kill). This also
puts the selected text in the kill ring. A second click at the same
place kills the secondary selection just made.
mouse-yank-secondary). This places point at the end of the
yanked text.
Double or triple clicking of M-Mouse-1 operates on words and lines, much like Mouse-1.
If mouse-yank-at-point is non-nil, M-Mouse-2
yanks at point. Then it does not matter precisely where you click; all
that matters is which window you click on. See Mouse Commands.
Apart from the primary and secondary selection types, X supports a clipboard selection type which is used by some applications, particularly under OpenWindows and Gnome.
The command M-x menu-bar-enable-clipboard makes the Cut,
Paste and Copy menu items, as well as the keys of the same
names, all use the clipboard.
You can customize the variable x-select-enable-clipboard to make
the Emacs yank functions consult the clipboard before the primary
selection, and to make the kill functions to store in the clipboard as
well as the primary selection. Otherwise they do not access the
clipboard at all. Using the clipboard is the default on MS-Windows,
unlike most systems.
Some read-only Emacs buffers include references you can follow, or commands you can activate. These include names of files, of buffers, of possible completions, of matches for a pattern, as well as the buttons in Help buffers and customization buffers. You can follow the reference or activate the command by moving point to it and typing <RET>. You can also do this with the mouse, using either Mouse-1 or Mouse-2.
Since yanking text into a read-only buffer is not allowed, these buffers generally define Mouse-2 to follow a reference or activate a command. For example, if you click Mouse-2 on a file name in a Dired buffer, you visit that file. If you click Mouse-2 on an error message in the ‘*Compilation*’ buffer, you go to the source code for that error message. If you click Mouse-2 on a completion in the ‘*Completions*’ buffer, you choose that completion.
However, most applications use Mouse-1 to do this sort of thing, so Emacs implements this too. If you click Mouse-1 quickly on a reference or button, it follows or activates. If you click slowly, it moves point as usual. Dragging, meaning moving the mouse while it is held down, also has its usual behavior of setting the region.
Normally, the Mouse-1 click behavior is performed on links in
any window. The variable mouse-1-click-in-non-selected-windows
controls whether Mouse-1 has this behavior even in non-selected
windows, or only in the selected window.
You can usually tell when Mouse-1 and Mouse-2 have this
special sort of meaning because the sensitive text highlights when you
move the mouse over it. The variable mouse-highlight controls
whether to do this highlighting always (even when such text appears
where the mouse already is), never, or only immediately after you move
the mouse.
In Emacs versions before 22, only Mouse-2 follows links and
Mouse-1 always sets points. If you prefer this behavior, set
the variable mouse-1-click-follows-link to nil. This
variable also lets you choose various other alternatives for following
links with the mouse. Type C-h v mouse-1-click-follows-link <RET>
for more details.
Mouse clicks modified with the <CTRL> and <SHIFT> keys bring up menus.
The MSB (“mouse select buffer”) global minor mode makes this
menu smarter and more customizable. See Buffer Menus.
You can use mouse clicks on window mode lines to select and manipulate windows.
Some areas of the mode line, such as the buffer name and the major mode name, have their own special mouse bindings. These areas are highlighted when you hold the mouse over them, and information about the special bindings will be displayed (see Tooltips).
You can also click on areas of the mode line that do not have special mouse bindings of their own. This has the following effects:
C-Mouse-2 on a scroll bar splits the corresponding window vertically. See Split Window.
The prefix key C-x 5 is analogous to C-x 4, with parallel subcommands. The difference is that C-x 5 commands create a new frame rather than just a new window in the selected frame (see Pop Up Window). If an existing visible or iconified frame already displays the requested material, these commands use the existing frame, after raising or deiconifying as necessary.
The various C-x 5 commands differ in how they find or create the buffer to select:
make-frame-command).
switch-to-buffer-other-frame.
find-file-other-frame. See Visiting.
dired-other-frame. See Dired.
mail-other-frame. It is the other-frame variant of C-x m.
See Sending Mail.
find-tag-other-frame, the multiple-frame variant of M-..
See Tags.
find-file-read-only-other-frame.
See Visiting.
You can control the appearance of new frames you create by setting the
frame parameters in default-frame-alist. You can use the
variable initial-frame-alist to specify parameters that affect
only the initial frame. See Initial Parameters, for more information.
The easiest way to specify the principal font for all your Emacs
frames is with an X resource (see Font X), but you can also do it by
modifying default-frame-alist to specify the font
parameter, as shown here:
(add-to-list 'default-frame-alist '(font . "10x20"))
Here's a similar example for specifying a foreground color:
(add-to-list 'default-frame-alist '(foreground-color . "blue"))
The following commands let you create, delete and operate on frames:
iconify-or-deiconify-frame).
The normal meaning of C-z, to suspend Emacs, is not useful under a
window system, so it has a different binding in that case.
If you type this command on an Emacs frame's icon, it deiconifies the frame.
delete-frame). This is not allowed if
there is only one frame.
To make the command C-x 5 o work properly, you must tell Emacs
how the system (or the window manager) generally handles
focus-switching between windows. There are two possibilities: either
simply moving the mouse onto a window selects it (gives it focus), or
you have to click on it in a suitable way to do so. Unfortunately
there is no way Emacs can find out automatically which way the system
handles this, so you have to explicitly say, by setting the variable
focus-follows-mouse. If just moving the mouse onto a window
selects it, that variable should be t; if a click is necessary,
the variable should be nil.
The speedbar is a special frame for conveniently navigating in or operating on another frame. The speedbar, when it exists, is always associated with a specific frame, called its attached frame; all speedbar operations act on that frame.
Type M-x speedbar to create the speedbar and associate it with the current frame. To dismiss the speedbar, type M-x speedbar again, or select the speedbar and type q. (You can also delete the speedbar frame like any other Emacs frame.) If you wish to associate the speedbar with a different frame, dismiss it and call M-x speedbar from that frame.
The speedbar can operate in various modes. Its default mode is File Display mode, which shows the files in the current directory of the selected window of the attached frame, one file per line. Clicking on a file name visits that file in the selected window of the attached frame, and clicking on a directory name shows that directory in the speedbar (see Mouse References). Each line also has a box, ‘[+]’ or ‘<+>’, that you can click on to expand the contents of that item. Expanding a directory adds the contents of that directory to the speedbar display, underneath the directory's own line. Expanding an ordinary file adds a list of the tags in that file to the speedbar display; you can click on a tag name to jump to that tag in the selected window of the attached frame. When a file or directory is expanded, the ‘[+]’ changes to ‘[-]’; you can click on that box to contract the item, hiding its contents.
You navigate through the speedbar using the keyboard, too. Typing RET while point is on a line in the speedbar is equivalent to clicking the item on the current line, and SPC expands or contracts the item. U displays the parent directory of the current directory. To copy, delete, or rename the file on the current line, type C, D, and R respectively. To create a new directory, type M.
Another general-purpose speedbar mode is Buffer Display mode; in this mode, the speedbar displays a list of Emacs buffers. To switch to this mode, type b in the speedbar. To return to File Display mode, type f. You can also change the display mode by clicking mouse-3 anywhere in the speedbar window (or mouse-1 on the mode-line) and selecting ‘Displays’ in the pop-up menu.
Some major modes, including Rmail mode, Info, and GUD, have specialized ways of putting useful items into the speedbar for you to select. For example, in Rmail mode, the speedbar shows a list of Rmail files, and lets you move the current message to another Rmail file by clicking on its ‘<M>’ box.
For more details on using and programming the speedbar, See Speedbar.
A single Emacs can talk to more than one X display. Initially, Emacs
uses just one display—the one specified with the DISPLAY
environment variable or with the ‘--display’ option (see Initial Options). To connect to another display, use the command
make-frame-on-display:
A single X server can handle more than one screen. When you open frames on two screens belonging to one server, Emacs knows they share a single keyboard, and it treats all the commands arriving from these screens as a single stream of input.
When you open frames on different X servers, Emacs makes a separate input stream for each server. This way, two users can type simultaneously on the two displays, and Emacs will not garble their input. Each server also has its own selected frame. The commands you enter with a particular X server apply to that server's selected frame.
Despite these features, people using the same Emacs job from different displays can still interfere with each other if they are not careful. For example, if any one types C-x C-c, that exits the Emacs job for all of them!
You can make certain chosen buffers, for which Emacs normally creates
a second window when you have just one window, appear in special frames
of their own. To do this, set the variable
special-display-buffer-names to a list of buffer names; any
buffer whose name is in that list automatically gets a special frame,
when an Emacs command wants to display it “in another window.”
For example, if you set the variable this way,
(setq special-display-buffer-names
'("*Completions*" "*grep*" "*tex-shell*"))
then completion lists, grep output and the TeX mode shell
buffer get individual frames of their own. These frames, and the
windows in them, are never automatically split or reused for any other
buffers. They continue to show the buffers they were created for,
unless you alter them by hand. Killing the special buffer deletes its
frame automatically.
More generally, you can set special-display-regexps to a list
of regular expressions; then a buffer gets its own frame if its name
matches any of those regular expressions. (Once again, this applies only
to buffers that normally get displayed for you in a separate window.)
The variable special-display-frame-alist specifies the frame
parameters for these frames. It has a default value, so you don't need
to set it.
For those who know Lisp, an element of
special-display-buffer-names or special-display-regexps
can also be a list. Then the first element is the buffer name or
regular expression; the rest of the list specifies how to create the
frame. It can be an association list specifying frame parameter
values; these values take precedence over parameter values specified
in special-display-frame-alist. If you specify the symbol
same-window as a “frame parameter” in this list, with a
non-nil value, that means to use the selected window if
possible. If you use the symbol same-frame as a “frame
parameter” in this list, with a non-nil value, that means to
use the selected frame if possible.
Alternatively, the value can have this form:
(function args...)
where function is a symbol. Then the frame is constructed by calling function; its first argument is the buffer, and its remaining arguments are args.
An analogous feature lets you specify buffers which should be
displayed in the selected window. See Force Same Window. The
same-window feature takes precedence over the special-frame feature;
therefore, if you add a buffer name to
special-display-buffer-names and it has no effect, check to see
whether that feature is also in use for the same buffer name.
This section describes commands for altering the display style and window management behavior of the selected frame.
Note that this auto-raise feature is implemented by Emacs itself. Some
window managers also implement auto-raise. If you enable auto-raise for
Emacs frames in your X window manager, it should work, but it is beyond
Emacs's control and therefore auto-raise-mode has no effect on
it.
The command auto-lower-mode has no effect on auto-lower
implemented by the X window manager. To control that, you must use
the appropriate window manager features.
default face (see Faces). For example, if the principal font
has a height of 12 pt, all text will be drawn in 12 pt fonts, unless you
use another face that specifies a different height. See Font X, for
ways to list the available fonts on your system.
You can also set a frame's principal font through a pop-up menu. Press S-Mouse-1 to activate this menu.
In Emacs versions that use an X toolkit, the color-setting and font-setting functions don't affect menus and the menu bar, since they are displayed by their own widget classes. To change the appearance of the menus and menu bar, you must use X resources (see Resources). See Colors, regarding colors. See Font X, regarding choice of font.
Colors, fonts, and other attributes of the frame's display can also
be customized by setting frame parameters in the variable
default-frame-alist (see Creating Frames). For a detailed
description of frame parameters and customization, see Frame Parameters.
When using X, Emacs normally makes a scroll bar at the left of each Emacs window.5 The scroll bar runs the height of the window, and shows a moving rectangular inner box which represents the portion of the buffer currently displayed. The entire height of the scroll bar represents the entire length of the buffer.
You can use Mouse-2 (normally, the middle button) in the scroll bar to move or drag the inner box up and down. If you move it to the top of the scroll bar, you see the top of the buffer. If you move it to the bottom of the scroll bar, you see the bottom of the buffer.
The left and right buttons in the scroll bar scroll by controlled increments. Mouse-1 (normally, the left button) moves the line at the level where you click up to the top of the window. Mouse-3 (normally, the right button) moves the line at the top of the window down to the level where you click. By clicking repeatedly in the same place, you can scroll by the same distance over and over.
You can also click C-Mouse-2 in the scroll bar to split a window vertically. The split occurs on the line where you click.
You can enable or disable Scroll Bar mode with the command M-x
scroll-bar-mode. With no argument, it toggles the use of scroll bars.
With an argument, it turns use of scroll bars on if and only if the
argument is positive. This command applies to all frames, including
frames yet to be created. Customize the variable scroll-bar-mode
to control the use of scroll bars at startup. You can use it to specify
that they are placed at the right of windows if you prefer that. You
have to set this variable through the ‘Customize’ interface
(see Easy Customization). Otherwise, it will not work properly.
You can use the X resource ‘verticalScrollBars’ to control the
initial setting of Scroll Bar mode similarly. See Resources.
To enable or disable scroll bars for just the selected frame, use the command M-x toggle-scroll-bar.
You can control the scroll bar width by changing the value of the
scroll-bar-width frame parameter.
Some mice have a “wheel” instead of a third button. You can usually click the wheel to act as either Mouse-2 or Mouse-3, depending on the setup. You can also use the wheel to scroll windows instead of using the scroll bar or keyboard commands. Mouse wheel support only works if the system generates appropriate events; whenever possible, it is turned on by default. To toggle this feature, use M-x mouse-wheel-mode.
The variables mouse-wheel-follow-mouse and
mouse-wheel-scroll-amount determine where and by how much
buffers are scrolled. The variable
mouse-wheel-progressive-speed determines whether the scroll
speed is linked to how fast you move the wheel.
Emacs supports drag and drop using the mouse. For instance, dropping text onto an Emacs frame inserts the text where it is dropped. Dropping a file onto an Emacs frame visits that file. As a special case, dropping the file on a Dired buffer moves or copies the file (according to the conventions of the application it came from) into the directory displayed in that buffer.
Dropping a file normally visits it in the window you drop it on. If
you prefer to visit the file in a new window in such cases, customize
the variable dnd-open-file-other-window.
The drag and drop protocols XDND, Motif and the old KDE 1.x protocol are currently supported.
You can turn display of menu bars on or off with M-x
menu-bar-mode or by customizing the variable menu-bar-mode.
With no argument, this command toggles Menu Bar mode, a
minor mode. With an argument, the command turns Menu Bar mode on if the
argument is positive, off if the argument is not positive. You can use
the X resource ‘menuBarLines’ to control the initial setting of
Menu Bar mode. See Resources.
Expert users often turn off the menu bar, especially on text-only terminals, where this makes one additional line available for text. If the menu bar is off, you can still pop up a menu of its contents with C-Mouse-3 on a display which supports pop-up menus. See Menu Mouse Clicks.
See Menu Bar, for information on how to invoke commands with the menu bar. See X Resources, for how to customize the menu bar menus.
The tool bar is a line (or lines) of icons at the top of the Emacs window, just below the menu bar. You can click on these icons with the mouse to do various jobs.
The global tool bar contains general commands. Some major modes define their own tool bars to replace it. A few “special” modes that are not designed for ordinary editing remove some items from the global tool bar.
Tool bars work only on a graphical display. The tool bar uses colored XPM icons if Emacs was built with XPM support. Otherwise, the tool bar uses monochrome icons (PBM or XBM format).
You can turn display of tool bars on or off with M-x
tool-bar-mode or by customizing the option tool-bar-mode.
A dialog box is a special kind of menu for asking you a yes-or-no question or some other special question. Many Emacs commands use a dialog box to ask a yes-or-no question, if you used the mouse to invoke the command to begin with.
You can customize the variable use-dialog-box to suppress the
use of dialog boxes. This also controls whether to use file selection
windows (but those are not supported on all platforms).
A file selection window is a special kind of dialog box for asking for file names.
You can customize the variable use-file-dialog to suppress the
use of file selection windows even if you still want other kinds
of dialogs. This variable has no effect if you have suppressed all dialog
boxes with the variable use-dialog-box.
For Gtk+ version 2.4 and 2.6, you can make Emacs use the old file dialog
by setting the variable x-use-old-gtk-file-dialog to a non-nil
value. If Emacs is built with a Gtk+ version that has only one file dialog,
the setting of this variable has no effect.
Tooltips are small windows that display text information at the current mouse position. They activate when there is a pause in mouse movement. There are two types of tooltip: help tooltips and GUD tooltips.
Help tooltips typically display over text—including the mode line—but may be also available for many other parts of the Emacs frame such as the tool bar and menu items.
You can toggle help tooltips (Tooltip mode) with the command M-x tooltip-mode. When Tooltip mode is disabled, the help text is displayed in the echo area instead.
GUD tooltips show values of variables. They are useful when you are debugging a program. See Debugger Operation.
The variables tooltip-delay specifies how long Emacs should
wait before displaying a tooltip. For additional customization
options for displaying tooltips, use M-x customize-group
<RET> tooltip <RET>. See X Resources, for information on
customizing the windows that display tooltips.
Mouse Avoidance mode keeps the window system mouse pointer away from
point, to avoid obscuring text. Whenever it moves the mouse, it also
raises the frame. To use Mouse Avoidance mode, customize the variable
mouse-avoidance-mode. You can set this to various values to
move the mouse in several ways:
banishexilejumpanimatejump, but shows steps along the way for illusion of motion;
cat-and-mouseanimate;
proteusanimate, but changes the shape of the mouse pointer too.
You can also use the command M-x mouse-avoidance-mode to enable the mode.
If your terminal does not have a window system that Emacs supports, then it can display only one Emacs frame at a time. However, you can still create multiple Emacs frames, and switch between them. Switching frames on these terminals is much like switching between different window configurations.
Use C-x 5 2 to create a new frame and switch to it; use C-x 5 o to cycle through the existing frames; use C-x 5 0 to delete the current frame.
Each frame has a number to distinguish it. If your terminal can display only one frame at a time, the selected frame's number n appears near the beginning of the mode line, in the form ‘Fn’.
‘Fn’ is actually the frame's name. You can also specify a different name if you wish, and you can select a frame by its name. Use the command M-x set-frame-name <RET> name <RET> to specify a new name for the selected frame, and use M-x select-frame-by-name <RET> name <RET> to select a frame according to its name. The name you specify appears in the mode line when the frame is selected.
Some terminal emulators under X support mouse clicks in the terminal
window. In a terminal emulator which is compatible with xterm,
you can use M-x xterm-mouse-mode to give Emacs control over
simple use of the mouse—basically, only non-modified single clicks
are supported. The normal xterm mouse functionality for such
clicks is still available by holding down the SHIFT key when you
press the mouse button.
Xterm Mouse mode is a global minor mode (see Minor Modes). Repeating the command turns the mode off again.
Emacs supports a wide variety of international character sets, including European and Vietnamese variants of the Latin alphabet, as well as Cyrillic, Devanagari (for Hindi and Marathi), Ethiopic, Greek, Han (for Chinese and Japanese), Hangul (for Korean), Hebrew, IPA, Kannada, Lao, Malayalam, Tamil, Thai, Tibetan, and Vietnamese scripts. These features have been merged from the modified version of Emacs known as MULE (for “MULti-lingual Enhancement to GNU Emacs”)
Emacs also supports various encodings of these characters used by other internationalized software, such as word processors and mailers.
Emacs allows editing text with international characters by supporting all the related activities:
The rest of this chapter describes these issues in detail.
The users of international character sets and scripts have established many more-or-less standard coding systems for storing files. Emacs internally uses a single multibyte character encoding, so that it can intermix characters from all these scripts in a single buffer or string. This encoding represents each non-ASCII character as a sequence of bytes in the range 0200 through 0377. Emacs translates between the multibyte character encoding and various other coding systems when reading and writing files, when exchanging data with subprocesses, and (in some cases) in the C-q command (see Multibyte Conversion).
The command C-h h (view-hello-file) displays the file
etc/HELLO, which shows how to say “hello” in many languages.
This illustrates various scripts. If some characters can't be
displayed on your terminal, they appear as ‘?’ or as hollow boxes
(see Undisplayable Characters).
Keyboards, even in the countries where these character sets are used, generally don't have keys for all the characters in them. So Emacs supports various input methods, typically one for each script or language, to make it convenient to type them.
The prefix key C-x <RET> is used for commands that pertain to multibyte characters, coding systems, and input methods.
You can enable or disable multibyte character support, either for Emacs as a whole, or for a single buffer. When multibyte characters are disabled in a buffer, then each byte in that buffer represents a character, even codes 0200 through 0377. The old features for supporting the European character sets, ISO Latin-1 and ISO Latin-2, work as they did in Emacs 19 and also work for the other ISO 8859 character sets.
However, there is no need to turn off multibyte character support to use ISO Latin; the Emacs multibyte character set includes all the characters in these character sets, and Emacs can translate automatically to and from the ISO codes.
By default, Emacs starts in multibyte mode, because that allows you to use all the supported languages and scripts without limitations.
To edit a particular file in unibyte representation, visit it using
find-file-literally. See Visiting. To convert a buffer in
multibyte representation into a single-byte representation of the same
characters, the easiest way is to save the contents in a file, kill the
buffer, and find the file again with find-file-literally. You
can also use C-x <RET> c
(universal-coding-system-argument) and specify ‘raw-text’ as
the coding system with which to find or save a file. See Specify Coding. Finding a file as ‘raw-text’ doesn't disable format
conversion, uncompression and auto mode selection as
find-file-literally does.
To turn off multibyte character support by default, start Emacs with
the ‘--unibyte’ option (see Initial Options), or set the
environment variable EMACS_UNIBYTE. You can also customize
enable-multibyte-characters or, equivalently, directly set the
variable default-enable-multibyte-characters to nil in
your init file to have basically the same effect as ‘--unibyte’.
To convert a unibyte session to a multibyte session, set
default-enable-multibyte-characters to t. Buffers which
were created in the unibyte session before you turn on multibyte support
will stay unibyte. You can turn on multibyte support in a specific
buffer by invoking the command toggle-enable-multibyte-characters
in that buffer.
With ‘--unibyte’, multibyte strings are not created during initialization from the values of environment variables, /etc/passwd entries etc. that contain non-ASCII 8-bit characters.
Emacs normally loads Lisp files as multibyte, regardless of whether you used ‘--unibyte’. This includes the Emacs initialization file, .emacs, and the initialization files of Emacs packages such as Gnus. However, you can specify unibyte loading for a particular Lisp file, by putting ‘-*-unibyte: t;-*-’ in a comment on the first line (see File Variables). Then that file is always loaded as unibyte text, even if you did not start Emacs with ‘--unibyte’. The motivation for these conventions is that it is more reliable to always load any particular Lisp file in the same way. However, you can load a Lisp file as unibyte, on any one occasion, by typing C-x <RET> c raw-text <RET> immediately before loading it.
The mode line indicates whether multibyte character support is enabled in the current buffer. If it is, there are two or more characters (most often two dashes) before the colon near the beginning of the mode line. When multibyte characters are not enabled, just one dash precedes the colon.
All supported character sets are supported in Emacs buffers whenever multibyte characters are enabled; there is no need to select a particular language in order to display its characters in an Emacs buffer. However, it is important to select a language environment in order to set various defaults. The language environment really represents a choice of preferred script (more or less) rather than a choice of language.
The language environment controls which coding systems to recognize when reading text (see Recognize Coding). This applies to files, incoming mail, netnews, and any other text you read into Emacs. It may also specify the default coding system to use when you create a file. Each language environment also specifies a default input method.
To select a language environment, you can customize the variable
current-language-environment or use the command M-x
set-language-environment. It makes no difference which buffer is
current when you use this command, because the effects apply globally to
the Emacs session. The supported language environments include:
Belarusian, Brazilian Portuguese, Bulgarian, Chinese-BIG5, Chinese-CNS, Chinese-EUC-TW, Chinese-GB, Croatian, Cyrillic-ALT, Cyrillic-ISO, Cyrillic-KOI8, Czech, Devanagari, Dutch, English, Ethiopic, French, Georgian, German, Greek, Hebrew, IPA, Italian, Japanese, Kannada, Korean, Lao, Latin-1, Latin-2, Latin-3, Latin-4, Latin-5, Latin-6, Latin-7, Latin-8 (Celtic), Latin-9 (updated Latin-1 with the Euro sign), Latvian, Lithuanian, Malayalam, Polish, Romanian, Russian, Slovak, Slovenian, Spanish, Swedish, Tajik, Tamil, Thai, Tibetan, Turkish, UTF-8 (for a setup which prefers Unicode characters and files encoded in UTF-8), Ukrainian, Vietnamese, Welsh, and Windows-1255 (for a setup which prefers Cyrillic characters and files encoded in Windows-1255).
To display the script(s) used by your language environment on a graphical display, you need to have a suitable font. If some of the characters appear as empty boxes, you should install the GNU Intlfonts package, which includes fonts for most supported scripts.6 See Fontsets, for more details about setting up your fonts.
Some operating systems let you specify the character-set locale you
are using by setting the locale environment variables LC_ALL,
LC_CTYPE, or LANG.7 During startup, Emacs looks up your character-set locale's
name in the system locale alias table, matches its canonical name
against entries in the value of the variables
locale-charset-language-names and locale-language-names,
and selects the corresponding language environment if a match is found.
(The former variable overrides the latter.) It also adjusts the display
table and terminal coding system, the locale coding system, the
preferred coding system as needed for the locale, and—last but not
least—the way Emacs decodes non-ASCII characters sent by your keyboard.
If you modify the LC_ALL, LC_CTYPE, or LANG
environment variables while running Emacs, you may want to invoke the
set-locale-environment function afterwards to readjust the
language environment from the new locale.
The set-locale-environment function normally uses the preferred
coding system established by the language environment to decode system
messages. But if your locale matches an entry in the variable
locale-preferred-coding-systems, Emacs uses the corresponding
coding system instead. For example, if the locale ‘ja_JP.PCK’
matches japanese-shift-jis in
locale-preferred-coding-systems, Emacs uses that encoding even
though it might normally use japanese-iso-8bit.
You can override the language environment chosen at startup with
explicit use of the command set-language-environment, or with
customization of current-language-environment in your init
file.
To display information about the effects of a certain language
environment lang-env, use the command C-h L lang-env
<RET> (describe-language-environment). This tells you which
languages this language environment is useful for, and lists the
character sets, coding systems, and input methods that go with it. It
also shows some sample text to illustrate scripts used in this language
environment. By default, this command describes the chosen language
environment.
You can customize any language environment with the normal hook
set-language-environment-hook. The command
set-language-environment runs that hook after setting up the new
language environment. The hook functions can test for a specific
language environment by checking the variable
current-language-environment. This hook is where you should
put non-default settings for specific language environment, such as
coding systems for keyboard input and terminal output, the default
input method, etc.
Before it starts to set up the new language environment,
set-language-environment first runs the hook
exit-language-environment-hook. This hook is useful for undoing
customizations that were made with set-language-environment-hook.
For instance, if you set up a special key binding in a specific language
environment using set-language-environment-hook, you should set
up exit-language-environment-hook to restore the normal binding
for that key.
An input method is a kind of character conversion designed specifically for interactive input. In Emacs, typically each language has its own input method; sometimes several languages which use the same characters can share one input method. A few languages support several input methods.
The simplest kind of input method works by mapping ASCII letters into another alphabet; this allows you to use one other alphabet instead of ASCII. The Greek and Russian input methods work this way.
A more powerful technique is composition: converting sequences of characters into one letter. Many European input methods use composition to produce a single non-ASCII letter from a sequence that consists of a letter followed by accent characters (or vice versa). For example, some methods convert the sequence a' into a single accented letter. These input methods have no special commands of their own; all they do is compose sequences of printing characters.
The input methods for syllabic scripts typically use mapping followed by composition. The input methods for Thai and Korean work this way. First, letters are mapped into symbols for particular sounds or tone marks; then, sequences of these which make up a whole syllable are mapped into one syllable sign.
Chinese and Japanese require more complex methods. In Chinese input
methods, first you enter the phonetic spelling of a Chinese word (in
input method chinese-py, among others), or a sequence of
portions of the character (input methods chinese-4corner and
chinese-sw, and others). One input sequence typically
corresponds to many possible Chinese characters. You select the one
you mean using keys such as C-f, C-b, C-n,
C-p, and digits, which have special meanings in this situation.
The possible characters are conceptually arranged in several rows,
with each row holding up to 10 alternatives. Normally, Emacs displays
just one row at a time, in the echo area; (i/j)
appears at the beginning, to indicate that this is the ith row
out of a total of j rows. Type C-n or C-p to
display the next row or the previous row.
Type C-f and C-b to move forward and backward among
the alternatives in the current row. As you do this, Emacs highlights
the current alternative with a special color; type C-<SPC>
to select the current alternative and use it as input. The
alternatives in the row are also numbered; the number appears before
the alternative. Typing a digit n selects the nth
alternative of the current row and uses it as input.
<TAB> in these Chinese input methods displays a buffer showing all the possible characters at once; then clicking Mouse-2 on one of them selects that alternative. The keys C-f, C-b, C-n, C-p, and digits continue to work as usual, but they do the highlighting in the buffer showing the possible characters, rather than in the echo area.
In Japanese input methods, first you input a whole word using phonetic spelling; then, after the word is in the buffer, Emacs converts it into one or more characters using a large dictionary. One phonetic spelling corresponds to a number of different Japanese words; to select one of them, use C-n and C-p to cycle through the alternatives.
Sometimes it is useful to cut off input method processing so that the
characters you have just entered will not combine with subsequent
characters. For example, in input method latin-1-postfix, the
sequence e ' combines to form an ‘e’ with an accent. What if
you want to enter them as separate characters?
One way is to type the accent twice; this is a special feature for entering the separate letter and accent. For example, e ' ' gives you the two characters ‘e'’. Another way is to type another letter after the e—something that won't combine with that—and immediately delete it. For example, you could type e e <DEL> ' to get separate ‘e’ and ‘'’.
Another method, more general but not quite as easy to type, is to use
C-\ C-\ between two characters to stop them from combining. This
is the command C-\ (toggle-input-method) used twice.
C-\ C-\ is especially useful inside an incremental search, because it stops waiting for more characters to combine, and starts searching for what you have already entered.
To find out how to input the character after point using the current input method, type C-u C-x =. See Position Info.
The variables input-method-highlight-flag and
input-method-verbose-flag control how input methods explain
what is happening. If input-method-highlight-flag is
non-nil, the partial sequence is highlighted in the buffer (for
most input methods—some disable this feature). If
input-method-verbose-flag is non-nil, the list of
possible characters to type next is displayed in the echo area (but
not when you are in the minibuffer).
describe-input-method).
By default, it describes the current input method (if any). This
description should give you the full details of how to use any
particular input method.
To choose an input method for the current buffer, use C-x
<RET> C-\ (set-input-method). This command reads the
input method name from the minibuffer; the name normally starts with the
language environment that it is meant to be used with. The variable
current-input-method records which input method is selected.
Input methods use various sequences of ASCII characters to stand for
non-ASCII characters. Sometimes it is useful to turn off the input
method temporarily. To do this, type C-\
(toggle-input-method). To reenable the input method, type
C-\ again.
If you type C-\ and you have not yet selected an input method, it prompts for you to specify one. This has the same effect as using C-x <RET> C-\ to specify an input method.
When invoked with a numeric argument, as in C-u C-\,
toggle-input-method always prompts you for an input method,
suggesting the most recently selected one as the default.
Selecting a language environment specifies a default input method for
use in various buffers. When you have a default input method, you can
select it in the current buffer by typing C-\. The variable
default-input-method specifies the default input method
(nil means there is none).
In some language environments, which support several different input
methods, you might want to use an input method different from the
default chosen by set-language-environment. You can instruct
Emacs to select a different default input method for a certain
language environment, if you wish, by using
set-language-environment-hook (see set-language-environment-hook). For example:
(defun my-chinese-setup ()
"Set up my private Chinese environment."
(if (equal current-language-environment "Chinese-GB")
(setq default-input-method "chinese-tonepy")))
(add-hook 'set-language-environment-hook 'my-chinese-setup)
This sets the default input method to be chinese-tonepy
whenever you choose a Chinese-GB language environment.
Some input methods for alphabetic scripts work by (in effect) remapping the keyboard to emulate various keyboard layouts commonly used for those scripts. How to do this remapping properly depends on your actual keyboard layout. To specify which layout your keyboard has, use the command M-x quail-set-keyboard-layout.
You can use the command M-x quail-show-key to show what key (or key sequence) to type in order to input the character following point, using the selected keyboard layout. The command C-u C-x = also shows that information in addition to the other information about the character.
To display a list of all the supported input methods, type M-x list-input-methods. The list gives information about each input method, including the string that stands for it in the mode line.
When multibyte characters are enabled, character codes 0240 (octal) through 0377 (octal) are not really legitimate in the buffer. The valid non-ASCII printing characters have codes that start from 0400.
If you type a self-inserting character in the range 0240 through 0377, or if you use C-q to insert one, Emacs assumes you intended to use one of the ISO Latin-n character sets, and converts it to the Emacs code representing that Latin-n character. You select which ISO Latin character set to use through your choice of language environment If you do not specify a choice, the default is Latin-1.
If you insert a character in the range 0200 through 0237, which
forms the eight-bit-control character set, it is inserted
literally. You should normally avoid doing this since buffers
containing such characters have to be written out in either the
emacs-mule or raw-text coding system, which is usually
not what you want.
Users of various languages have established many more-or-less standard coding systems for representing them. Emacs does not use these coding systems internally; instead, it converts from various coding systems to its own system when reading data, and converts the internal coding system to other coding systems when writing data. Conversion is possible in reading or writing files, in sending or receiving from the terminal, and in exchanging data with subprocesses.
Emacs assigns a name to each coding system. Most coding systems are
used for one language, and the name of the coding system starts with the
language name. Some coding systems are used for several languages;
their names usually start with ‘iso’. There are also special
coding systems no-conversion, raw-text and
emacs-mule which do not convert printing characters at all.
A special class of coding systems, collectively known as
codepages, is designed to support text encoded by MS-Windows and
MS-DOS software. The names of these coding systems are
cpnnnn, where nnnn is a 3- or 4-digit number of the
codepage. You can use these encodings just like any other coding
system; for example, to visit a file encoded in codepage 850, type
C-x <RET> c cp850 <RET> C-x C-f filename
<RET>8.
In addition to converting various representations of non-ASCII characters, a coding system can perform end-of-line conversion. Emacs handles three different conventions for how to separate lines in a file: newline, carriage-return linefeed, and just carriage-return.
The command C-h C (describe-coding-system) displays
information about particular coding systems. You can specify a coding
system name as the argument; alternatively, with an empty argument, it
describes the coding systems currently selected for various purposes,
both in the current buffer and as the defaults, and the priority list
for recognizing coding systems (see Recognize Coding).
To display a list of all the supported coding systems, type M-x list-coding-systems. The list gives information about each coding system, including the letter that stands for it in the mode line (see Mode Line).
Each of the coding systems that appear in this list—except for
no-conversion, which means no conversion of any kind—specifies
how and whether to convert printing characters, but leaves the choice of
end-of-line conversion to be decided based on the contents of each file.
For example, if the file appears to use the sequence carriage-return
linefeed to separate lines, DOS end-of-line conversion will be used.
Each of the listed coding systems has three variants which specify exactly what to do for end-of-line conversion:
...-unix...-dos...-macThese variant coding systems are omitted from the
list-coding-systems display for brevity, since they are entirely
predictable. For example, the coding system iso-latin-1 has
variants iso-latin-1-unix, iso-latin-1-dos and
iso-latin-1-mac.
The coding system raw-text is good for a file which is mainly
ASCII text, but may contain byte values above 127 which are not meant to
encode non-ASCII characters. With raw-text, Emacs copies those
byte values unchanged, and sets enable-multibyte-characters to
nil in the current buffer so that they will be interpreted
properly. raw-text handles end-of-line conversion in the usual
way, based on the data encountered, and has the usual three variants to
specify the kind of end-of-line conversion to use.
In contrast, the coding system no-conversion specifies no
character code conversion at all—none for non-ASCII byte values and
none for end of line. This is useful for reading or writing binary
files, tar files, and other files that must be examined verbatim. It,
too, sets enable-multibyte-characters to nil.
The easiest way to edit a file with no conversion of any kind is with
the M-x find-file-literally command. This uses
no-conversion, and also suppresses other Emacs features that
might convert the file contents before you see them. See Visiting.
The coding system emacs-mule means that the file contains
non-ASCII characters stored with the internal Emacs encoding. It
handles end-of-line conversion based on the data encountered, and has
the usual three variants to specify the kind of end-of-line conversion.
Emacs tries to recognize which coding system to use for a given text as an integral part of reading that text. (This applies to files being read, output from subprocesses, text from X selections, etc.) Emacs can select the right coding system automatically most of the time—once you have specified your preferences.
Some coding systems can be recognized or distinguished by which byte sequences appear in the data. However, there are coding systems that cannot be distinguished, not even potentially. For example, there is no way to distinguish between Latin-1 and Latin-2; they use the same byte values with different meanings.
Emacs handles this situation by means of a priority list of coding systems. Whenever Emacs reads a file, if you do not specify the coding system to use, Emacs checks the data against each coding system, starting with the first in priority and working down the list, until it finds a coding system that fits the data. Then it converts the file contents assuming that they are represented in this coding system.
The priority list of coding systems depends on the selected language environment (see Language Environments). For example, if you use French, you probably want Emacs to prefer Latin-1 to Latin-2; if you use Czech, you probably want Latin-2 to be preferred. This is one of the reasons to specify a language environment.
However, you can alter the coding system priority list in detail with the command M-x prefer-coding-system. This command reads the name of a coding system from the minibuffer, and adds it to the front of the priority list, so that it is preferred to all others. If you use this command several times, each use adds one element to the front of the priority list.
If you use a coding system that specifies the end-of-line conversion
type, such as iso-8859-1-dos, what this means is that Emacs
should attempt to recognize iso-8859-1 with priority, and should
use DOS end-of-line conversion when it does recognize iso-8859-1.
Sometimes a file name indicates which coding system to use for the
file. The variable file-coding-system-alist specifies this
correspondence. There is a special function
modify-coding-system-alist for adding elements to this list. For
example, to read and write all ‘.txt’ files using the coding system
china-iso-8bit, you can execute this Lisp expression:
(modify-coding-system-alist 'file "\\.txt\\'" 'chinese-iso-8bit)
The first argument should be file, the second argument should be
a regular expression that determines which files this applies to, and
the third argument says which coding system to use for these files.
Emacs recognizes which kind of end-of-line conversion to use based on
the contents of the file: if it sees only carriage-returns, or only
carriage-return linefeed sequences, then it chooses the end-of-line
conversion accordingly. You can inhibit the automatic use of
end-of-line conversion by setting the variable inhibit-eol-conversion
to non-nil. If you do that, DOS-style files will be displayed
with the ‘^M’ characters visible in the buffer; some people
prefer this to the more subtle ‘(DOS)’ end-of-line type
indication near the left edge of the mode line (see eol-mnemonic).
By default, the automatic detection of coding system is sensitive to escape sequences. If Emacs sees a sequence of characters that begin with an escape character, and the sequence is valid as an ISO-2022 code, that tells Emacs to use one of the ISO-2022 encodings to decode the file.
However, there may be cases that you want to read escape sequences
in a file as is. In such a case, you can set the variable
inhibit-iso-escape-detection to non-nil. Then the code
detection ignores any escape sequences, and never uses an ISO-2022
encoding. The result is that all escape sequences become visible in
the buffer.
The default value of inhibit-iso-escape-detection is
nil. We recommend that you not change it permanently, only for
one specific operation. That's because many Emacs Lisp source files
in the Emacs distribution contain non-ASCII characters encoded in the
coding system iso-2022-7bit, and they won't be
decoded correctly when you visit those files if you suppress the
escape sequence detection.
You can specify the coding system for a particular file using the
‘-*-...-*-’ construct at the beginning of a file, or a
local variables list at the end (see File Variables). You do this
by defining a value for the “variable” named coding. Emacs
does not really have a variable coding; instead of setting a
variable, this uses the specified coding system for the file. For
example, ‘-*-mode: C; coding: latin-1;-*-’ specifies use of the
Latin-1 coding system, as well as C mode. When you specify the coding
explicitly in the file, that overrides
file-coding-system-alist.
The variables auto-coding-alist,
auto-coding-regexp-alist and auto-coding-functions are
the strongest way to specify the coding system for certain patterns of
file names, or for files containing certain patterns; these variables
even override ‘-*-coding:-*-’ tags in the file itself. Emacs
uses auto-coding-alist for tar and archive files, to prevent it
from being confused by a ‘-*-coding:-*-’ tag in a member of the
archive and thinking it applies to the archive file as a whole.
Likewise, Emacs uses auto-coding-regexp-alist to ensure that
RMAIL files, whose names in general don't match any particular
pattern, are decoded correctly. One of the builtin
auto-coding-functions detects the encoding for XML files.
If Emacs recognizes the encoding of a file incorrectly, you can reread the file using the correct coding system by typing C-x <RET> r coding-system <RET>. To see what coding system Emacs actually used to decode the file, look at the coding system mnemonic letter near the left edge of the mode line (see Mode Line), or type C-h C <RET>.
The command unify-8859-on-decoding-mode enables a mode that
“unifies” the Latin alphabets when decoding text. This works by
converting all non-ASCII Latin-n characters to either Latin-1 or
Unicode characters. This way it is easier to use various
Latin-n alphabets together. In a future Emacs version we hope
to move towards full Unicode support and complete unification of
character sets.
Once Emacs has chosen a coding system for a buffer, it stores that
coding system in buffer-file-coding-system and uses that coding
system, by default, for operations that write from this buffer into a
file. This includes the commands save-buffer and
write-region. If you want to write files from this buffer using
a different coding system, you can specify a different coding system for
the buffer using set-buffer-file-coding-system (see Specify Coding).
You can insert any possible character into any Emacs buffer, but
most coding systems can only handle some of the possible characters.
This means that it is possible for you to insert characters that
cannot be encoded with the coding system that will be used to save the
buffer. For example, you could start with an ASCII file and insert a
few Latin-1 characters into it, or you could edit a text file in
Polish encoded in iso-8859-2 and add some Russian words to it.
When you save the buffer, Emacs cannot use the current value of
buffer-file-coding-system, because the characters you added
cannot be encoded by that coding system.
When that happens, Emacs tries the most-preferred coding system (set
by M-x prefer-coding-system or M-x
set-language-environment), and if that coding system can safely
encode all of the characters in the buffer, Emacs uses it, and stores
its value in buffer-file-coding-system. Otherwise, Emacs
displays a list of coding systems suitable for encoding the buffer's
contents, and asks you to choose one of those coding systems.
If you insert the unsuitable characters in a mail message, Emacs behaves a bit differently. It additionally checks whether the most-preferred coding system is recommended for use in MIME messages; if not, Emacs tells you that the most-preferred coding system is not recommended and prompts you for another coding system. This is so you won't inadvertently send a message encoded in a way that your recipient's mail software will have difficulty decoding. (If you do want to use the most-preferred coding system, you can still type its name in response to the question.)
When you send a message with Mail mode (see Sending Mail), Emacs has
four different ways to determine the coding system to use for encoding
the message text. It tries the buffer's own value of
buffer-file-coding-system, if that is non-nil. Otherwise,
it uses the value of sendmail-coding-system, if that is
non-nil. The third way is to use the default coding system for
new files, which is controlled by your choice of language environment,
if that is non-nil. If all of these three values are nil,
Emacs encodes outgoing mail using the Latin-1 coding system.
When you get new mail in Rmail, each message is translated
automatically from the coding system it is written in, as if it were a
separate file. This uses the priority list of coding systems that you
have specified. If a MIME message specifies a character set, Rmail
obeys that specification, unless rmail-decode-mime-charset is
nil.
For reading and saving Rmail files themselves, Emacs uses the coding
system specified by the variable rmail-file-coding-system. The
default value is nil, which means that Rmail files are not
translated (they are read and written in the Emacs internal character
code).
In cases where Emacs does not automatically choose the right coding system, you can use these commands to specify one:
The command C-x <RET> f
(set-buffer-file-coding-system) sets the file coding system for
the current buffer—in other words, it says which coding system to
use when saving or reverting the visited file. You specify which
coding system using the minibuffer. If you specify a coding system
that cannot handle all of the characters in the buffer, Emacs warns
you about the troublesome characters when you actually save the
buffer.
Another way to specify the coding system for a file is when you visit
the file. First use the command C-x <RET> c
(universal-coding-system-argument); this command uses the
minibuffer to read a coding system name. After you exit the minibuffer,
the specified coding system is used for the immediately following
command.
So if the immediately following command is C-x C-f, for example, it reads the file using that coding system (and records the coding system for when you later save the file). Or if the immediately following command is C-x C-w, it writes the file using that coding system. When you specify the coding system for saving in this way, instead of with C-x <RET> f, there is no warning if the buffer contains characters that the coding system cannot handle.
Other file commands affected by a specified coding system include C-x C-i and C-x C-v, as well as the other-window variants of C-x C-f. C-x <RET> c also affects commands that start subprocesses, including M-x shell (see Shell).
If the immediately following command does not use the coding system, then C-x <RET> c ultimately has no effect.
An easy way to visit a file with no conversion is with the M-x find-file-literally command. See Visiting.
The variable default-buffer-file-coding-system specifies the
choice of coding system to use when you create a new file. It applies
when you find a new file, and when you create a buffer and then save it
in a file. Selecting a language environment typically sets this
variable to a good choice of default coding system for that language
environment.
If you visit a file with a wrong coding system, you can correct this
with C-x <RET> r (revert-buffer-with-coding-system).
This visits the current file again, using a coding system you specify.
The command C-x <RET> t (set-terminal-coding-system)
specifies the coding system for terminal output. If you specify a
character code for terminal output, all characters output to the
terminal are translated into that coding system.
This feature is useful for certain character-only terminals built to support specific languages or character sets—for example, European terminals that support one of the ISO Latin character sets. You need to specify the terminal coding system when using multibyte text, so that Emacs knows which characters the terminal can actually handle.
By default, output to the terminal is not translated at all, unless Emacs can deduce the proper coding system from your terminal type or your locale specification (see Language Environments).
The command C-x <RET> k (set-keyboard-coding-system)
or the variable keyboard-coding-system specifies the coding
system for keyboard input. Character-code translation of keyboard
input is useful for terminals with keys that send non-ASCII
graphic characters—for example, some terminals designed for ISO
Latin-1 or subsets of it.
By default, keyboard input is translated based on your system locale
setting. If your terminal does not really support the encoding
implied by your locale (for example, if you find it inserts a
non-ASCII character if you type M-i), you will need to set
keyboard-coding-system to nil to turn off encoding.
You can do this by putting
(set-keyboard-coding-system nil)
in your ~/.emacs file.
There is a similarity between using a coding system translation for keyboard input, and using an input method: both define sequences of keyboard input that translate into single characters. However, input methods are designed to be convenient for interactive use by humans, and the sequences that are translated are typically sequences of ASCII printing characters. Coding systems typically translate sequences of non-graphic characters.
The command C-x <RET> x (set-selection-coding-system)
specifies the coding system for sending selected text to the window
system, and for receiving the text of selections made in other
applications. This command applies to all subsequent selections, until
you override it by using the command again. The command C-x
<RET> X (set-next-selection-coding-system) specifies the
coding system for the next selection made in Emacs or read by Emacs.
The command C-x <RET> p (set-buffer-process-coding-system)
specifies the coding system for input and output to a subprocess. This
command applies to the current buffer; normally, each subprocess has its
own buffer, and thus you can use this command to specify translation to
and from a particular subprocess by giving the command in the
corresponding buffer.
The default for translation of process input and output depends on the current language environment.
If a piece of text has already been inserted into a buffer using the wrong coding system, you can decode it again using M-x recode-region. This prompts you for the old coding system and the desired coding system, and acts on the text in the region.
The variable file-name-coding-system specifies a coding
system to use for encoding file names. If you set the variable to a
coding system name (as a Lisp symbol or a string), Emacs encodes file
names using that coding system for all file operations. This makes it
possible to use non-ASCII characters in file names—or, at
least, those non-ASCII characters which the specified coding
system can encode. Use C-x <RET> F
(set-file-name-coding-system) to specify this interactively.
If file-name-coding-system is nil, Emacs uses a default
coding system determined by the selected language environment. In the
default language environment, any non-ASCII characters in file names are
not encoded specially; they appear in the file system using the internal
Emacs representation.
Warning: if you change file-name-coding-system (or the
language environment) in the middle of an Emacs session, problems can
result if you have already visited files whose names were encoded using
the earlier coding system and cannot be encoded (or are encoded
differently) under the new coding system. If you try to save one of
these buffers under the visited file name, saving may use the wrong file
name, or it may get an error. If such a problem happens, use C-x
C-w to specify a new file name for that buffer.
If a mistake occurs when encoding a file name, use the command M-x recode-file-name to change the file name's coding system. This prompts for an existing file name, its old coding system, and the coding system to which you wish to convert.
The variable locale-coding-system specifies a coding system
to use when encoding and decoding system strings such as system error
messages and format-time-string formats and time stamps. That
coding system is also used for decoding non-ASCII keyboard input on X
Window systems. You should choose a coding system that is compatible
with the underlying system's text representation, which is normally
specified by one of the environment variables LC_ALL,
LC_CTYPE, and LANG. (The first one, in the order
specified above, whose value is nonempty is the one that determines
the text representation.)
A font for X typically defines shapes for a single alphabet or script. Therefore, displaying the entire range of scripts that Emacs supports requires a collection of many fonts. In Emacs, such a collection is called a fontset. A fontset is defined by a list of fonts, each assigned to handle a range of character codes.
Each fontset has a name, like a font. The available X fonts are defined by the X server; fontsets, however, are defined within Emacs itself. Once you have defined a fontset, you can use it within Emacs by specifying its name, anywhere that you could use a single font. Of course, Emacs fontsets can use only the fonts that the X server supports; if certain characters appear on the screen as hollow boxes, this means that the fontset in use for them has no font for those characters.10
Emacs creates two fontsets automatically: the standard fontset and the startup fontset. The standard fontset is most likely to have fonts for a wide variety of non-ASCII characters; however, this is not the default for Emacs to use. (By default, Emacs tries to find a font that has bold and italic variants.) You can specify use of the standard fontset with the ‘-fn’ option, or with the ‘Font’ X resource (see Font X). For example,
emacs -fn fontset-standard
A fontset does not necessarily specify a font for every character code. If a fontset specifies no font for a certain character, or if it specifies a font that does not exist on your system, then it cannot display that character properly. It will display that character as an empty box instead.
Emacs creates a standard fontset automatically according to the value
of standard-fontset-spec. This fontset's name is
-*-fixed-medium-r-normal-*-16-*-*-*-*-*-fontset-standard
or just ‘fontset-standard’ for short.
Bold, italic, and bold-italic variants of the standard fontset are created automatically. Their names have ‘bold’ instead of ‘medium’, or ‘i’ instead of ‘r’, or both.
If you specify a default ASCII font with the ‘Font’ resource or
the ‘-fn’ argument, Emacs generates a fontset from it
automatically. This is the startup fontset and its name is
fontset-startup. It does this by replacing the foundry,
family, add_style, and average_width fields of the
font name with ‘*’, replacing charset_registry field with
‘fontset’, and replacing charset_encoding field with
‘startup’, then using the resulting string to specify a fontset.
For instance, if you start Emacs this way,
emacs -fn "*courier-medium-r-normal--14-140-*-iso8859-1"
Emacs generates the following fontset and uses it for the initial X window frame:
-*-*-medium-r-normal-*-14-140-*-*-*-*-fontset-startup
With the X resource ‘Emacs.Font’, you can specify a fontset name just like an actual font name. But be careful not to specify a fontset name in a wildcard resource like ‘Emacs*Font’—that wildcard specification matches various other resources, such as for menus, and menus cannot handle fontsets.
You can specify additional fontsets using X resources named ‘Fontset-n’, where n is an integer starting from 0. The resource value should have this form:
fontpattern, [charsetname:fontname]...
fontpattern should have the form of a standard X font name, except for the last two fields. They should have the form ‘fontset-alias’.
The fontset has two names, one long and one short. The long name is fontpattern. The short name is ‘fontset-alias’. You can refer to the fontset by either name.
The construct ‘charset:font’ specifies which font to use (in this fontset) for one particular character set. Here, charset is the name of a character set, and font is the font to use for that character set. You can use this construct any number of times in defining one fontset.
For the other character sets, Emacs chooses a font based on fontpattern. It replaces ‘fontset-alias’ with values that describe the character set. For the ASCII character font, ‘fontset-alias’ is replaced with ‘ISO8859-1’.
In addition, when several consecutive fields are wildcards, Emacs collapses them into a single wildcard. This is to prevent use of auto-scaled fonts. Fonts made by scaling larger fonts are not usable for editing, and scaling a smaller font is not useful because it is better to use the smaller font in its own size, which is what Emacs does.
Thus if fontpattern is this,
-*-fixed-medium-r-normal-*-24-*-*-*-*-*-fontset-24
the font specification for ASCII characters would be this:
-*-fixed-medium-r-normal-*-24-*-ISO8859-1
and the font specification for Chinese GB2312 characters would be this:
-*-fixed-medium-r-normal-*-24-*-gb2312*-*
You may not have any Chinese font matching the above font specification. Most X distributions include only Chinese fonts that have ‘song ti’ or ‘fangsong ti’ in family field. In such a case, ‘Fontset-n’ can be specified as below:
Emacs.Fontset-0: -*-fixed-medium-r-normal-*-24-*-*-*-*-*-fontset-24,\
chinese-gb2312:-*-*-medium-r-normal-*-24-*-gb2312*-*
Then, the font specifications for all but Chinese GB2312 characters have ‘fixed’ in the family field, and the font specification for Chinese GB2312 characters has a wild card ‘*’ in the family field.
The function that processes the fontset resource value to create the
fontset is called create-fontset-from-fontset-spec. You can also
call this function explicitly to create a fontset.
See Font X, for more information about font naming in X.
There may be a some non-ASCII characters that your terminal cannot
display. Most non-windowing terminals support just a single character
set (use the variable default-terminal-coding-system
(see Specify Coding) to tell Emacs which one); characters which
can't be encoded in that coding system are displayed as ‘?’ by
default.
Windowing terminals can display a broader range of characters, but you may not have fonts installed for all of them; characters that have no font appear as a hollow box.
If you use Latin-1 characters but your terminal can't display Latin-1, you can arrange to display mnemonic ASCII sequences instead, e.g. ‘"o’ for o-umlaut. Load the library iso-ascii to do this.
If your terminal can display Latin-1, you can display characters
from other European character sets using a mixture of equivalent
Latin-1 characters and ASCII mnemonics. Customize the variable
latin1-display to enable this. The mnemonic ASCII
sequences mostly correspond to those of the prefix input methods.
The ISO 8859 Latin-n character sets define character codes in the range 0240 to 0377 octal (160 to 255 decimal) to handle the accented letters and punctuation needed by various European languages (and some non-European ones). If you disable multibyte characters, Emacs can still handle one of these character codes at a time. To specify which of these codes to use, invoke M-x set-language-environment and specify a suitable language environment such as ‘Latin-n’.
For more information about unibyte operation, see Enabling Multibyte. Note particularly that you probably want to ensure that your initialization files are read as unibyte if they contain non-ASCII characters.
Emacs can also display those characters, provided the terminal or font
in use supports them. This works automatically. Alternatively, if you
are using a window system, Emacs can also display single-byte characters
through fontsets, in effect by displaying the equivalent multibyte
characters according to the current language environment. To request
this, set the variable unibyte-display-via-language-environment
to a non-nil value.
If your terminal does not support display of the Latin-1 character
set, Emacs can display these characters as ASCII sequences which at
least give you a clear idea of what the characters are. To do this,
load the library iso-ascii. Similar libraries for other
Latin-n character sets could be implemented, but we don't have
them yet.
Normally non-ISO-8859 characters (decimal codes between 128 and 159
inclusive) are displayed as octal escapes. You can change this for
non-standard “extended” versions of ISO-8859 character sets by using the
function standard-display-8bit in the disp-table library.
There are two ways to input single-byte non-ASCII characters:
On a window system, you should not need to do anything special to use
these keys; they should simply work. On a text-only terminal, you
should use the command M-x set-keyboard-coding-system or the
variable keyboard-coding-system to specify which coding system
your keyboard uses (see Specify Coding). Enabling this feature
will probably require you to use ESC to type Meta characters;
however, on a console terminal or in xterm, you can arrange for
Meta to be converted to ESC and still be able type 8-bit
characters present directly on the keyboard or using Compose or
AltGr keys. See User Input.
C-x 8 works by loading the iso-transl library. Once that
library is loaded, the <ALT> modifier key, if the keyboard has
one, serves the same purpose as C-x 8: use <ALT> together
with an accent character to modify the following letter. In addition,
if the keyboard has keys for the Latin-1 “dead accent characters,”
they too are defined to compose with the following character, once
iso-transl is loaded.
Use C-x 8 C-h to list all the available C-x 8 translations.
Emacs groups all supported characters into disjoint charsets.
Each character code belongs to one and only one charset. For
historical reasons, Emacs typically divides an 8-bit character code
for an extended version of ASCII into two charsets: ASCII, which
covers the codes 0 through 127, plus another charset which covers the
“right-hand part” (the codes 128 and up). For instance, the
characters of Latin-1 include the Emacs charset ascii plus the
Emacs charset latin-iso8859-1.
Emacs characters belonging to different charsets may look the same,
but they are still different characters. For example, the letter
‘o’ with acute accent in charset latin-iso8859-1, used for
Latin-1, is different from the letter ‘o’ with acute accent in
charset latin-iso8859-2, used for Latin-2.
There are two commands for obtaining information about Emacs charsets. The command M-x list-charset-chars prompts for a name of a character set, and displays all the characters in that character set. The command M-x describe-character-set prompts for a charset name and displays information about that charset, including its internal representation within Emacs.
To find out which charset a character in the buffer belongs to, put point before it and type C-u C-x =.
Emacs provides many alternative major modes, each of which customizes Emacs for editing text of a particular sort. The major modes are mutually exclusive, and each buffer has one major mode at any time. The mode line normally shows the name of the current major mode, in parentheses (see Mode Line).
The least specialized major mode is called Fundamental mode. This mode has no mode-specific redefinitions or variable settings, so that each Emacs command behaves in its most general manner, and each user option variable is in its default state. For editing text of a specific type that Emacs knows about, such as Lisp code or English text, you should switch to the appropriate major mode, such as Lisp mode or Text mode.
Selecting a major mode changes the meanings of a few keys to become more specifically adapted to the language being edited. The ones that are changed frequently are <TAB>, <DEL>, and C-j. The prefix key C-c normally contains mode-specific commands. In addition, the commands which handle comments use the mode to determine how comments are to be delimited. Many major modes redefine the syntactical properties of characters appearing in the buffer. See Syntax.
The major modes fall into three major groups. The first group contains modes for normal text, either plain or with mark-up. It includes Text mode, HTML mode, SGML mode, TeX mode and Outline mode. The second group contains modes for specific programming languages. These include Lisp mode (which has several variants), C mode, Fortran mode, and others. The remaining major modes are not intended for use on users' files; they are used in buffers created for specific purposes by Emacs, such as Dired mode for buffers made by Dired (see Dired), Mail mode for buffers made by C-x m (see Sending Mail), and Shell mode for buffers used for communicating with an inferior shell process (see Interactive Shell).
Most programming-language major modes specify that only blank lines separate paragraphs. This is to make the paragraph commands useful. (See Paragraphs.) They also cause Auto Fill mode to use the definition of <TAB> to indent the new lines it creates. This is because most lines in a program are usually indented (see Indentation).
You can select a major mode explicitly for the current buffer, but most of the time Emacs determines which mode to use based on the file name or on special text in the file.
Explicit selection of a new major mode is done with a M-x command.
From the name of a major mode, add -mode to get the name of a
command to select that mode. Thus, you can enter Lisp mode by executing
M-x lisp-mode.
When you visit a file, Emacs usually chooses the right major mode based
on the file's name. For example, files whose names end in ‘.c’ are
edited in C mode. The correspondence between file names and major modes is
controlled by the variable auto-mode-alist. Its value is a list in
which each element has this form,
(regexp . mode-function)
or this form,
(regexp mode-function flag)
For example, one element normally found in the list has the form
("\\.c\\'" . c-mode), and it is responsible for selecting C
mode for files whose names end in .c. (Note that ‘\\’ is
needed in Lisp syntax to include a ‘\’ in the string, which must
be used to suppress the special meaning of ‘.’ in regexps.) If
the element has the form (regexp mode-function
flag) and flag is non-nil, then after calling
mode-function, Emacs discards the suffix that matched
regexp and searches the list again for another match.
Sometimes the major mode is determined from the way the file's text
begins. The variable magic-mode-alist controls this. Its value
is a list of elements of this form:
(regexp . mode-function)
This looks like an element of auto-mode-alist, but it doesn't work
the same: this regexp is matched against the text at the start
of the buffer, not against the file name. magic-mode-alist
takes priority over auto-mode-alist.
You can specify the major mode to use for editing a certain file by special text in the first nonblank line of the file. The mode name should appear in this line both preceded and followed by ‘-*-’. Other text may appear on the line as well. For example,
;-*-Lisp-*-
tells Emacs to use Lisp mode. Such an explicit specification overrides any defaults based on the file name. Note how the semicolon is used to make Lisp treat this line as a comment.
Another format of mode specification is
-*- mode: modename;-*-
which allows you to specify local variables as well, like this:
-*- mode: modename; var: value; ... -*-
See File Variables, for more information about this.
When a file's contents begin with ‘#!’, it can serve as an executable shell command, which works by running an interpreter named on the file's first line. The rest of the file is used as input to the interpreter.
When you visit such a file in Emacs, if the file's name does not
specify a major mode, Emacs uses the interpreter name on the first line
to choose a mode. If the first line is the name of a recognized
interpreter program, such as ‘perl’ or ‘tcl’, Emacs uses a
mode appropriate for programs for that interpreter. The variable
interpreter-mode-alist specifies the correspondence between
interpreter program names and major modes.
When the first line starts with ‘#!’, you cannot (on many systems) use the ‘-*-’ feature on the first line, because the system would get confused when running the interpreter. So Emacs looks for ‘-*-’ on the second line in such files as well as on the first line.
When you visit a file that does not specify a major mode to use, or
when you create a new buffer with C-x b, the variable
default-major-mode specifies which major mode to use. Normally
its value is the symbol fundamental-mode, which specifies
Fundamental mode. If default-major-mode is nil, the major
mode is taken from the previously current buffer.
If you change the major mode of a buffer, you can go back to the major
mode Emacs would choose automatically: use the command M-x
normal-mode to do this. This is the same function that
find-file calls to choose the major mode. It also processes
the file's ‘-*-’ line or local variables list (if any).
See File Variables.
The commands C-x C-w and set-visited-file-name change to
a new major mode if the new file name implies a mode (see Saving).
(C-x C-s does this too, if the buffer wasn't visiting a file.)
However, this does not happen if the buffer contents specify a major
mode, and certain “special” major modes do not allow the mode to
change. You can turn off this mode-changing feature by setting
change-major-mode-with-file-name to nil.
This chapter describes the Emacs commands that add, remove, or adjust indentation.
newline-and-indent).
delete-indentation).
This would cancel the effect of a preceding C-j.
split-line).
back-to-indentation).
indent-region).
indent-rigidly).
tab-to-tab-stop).
Emacs supports four general categories of operations that could all be called `indentation':
A tab character is displayed as a stretch of whitespace which extends to the next display tab stop position, and the default width of a tab stop is eight. See Display Custom, for more details.
indent-relative.
Type <TAB> to do syntax-driven indentation, in a mode that supports it. It realigns the current line according with the syntax of the preceding lines. No matter where in the line you are when you type <TAB>, it aligns the line as a whole.
Normally, most of the above methods insert an optimal mix of tabs and spaces to align to the desired column. See Just Spaces, for how to disable use of tabs. However, C-q <TAB> always inserts a tab, even when tabs are disabled for the indentation commands.
To move over the indentation on a line, do M-m
(back-to-indentation). This command, given anywhere on a line,
positions point at the first nonblank character on the line, if any,
or else at the end of the line.
To insert an indented line before the current line, do C-a C-o <TAB>. To make an indented line after the current line, use C-e C-j.
If you just want to insert a tab character in the buffer, you can type C-q <TAB>.
C-M-o (split-line) moves the text from point to the end of
the line vertically down, so that the current line becomes two lines.
C-M-o first moves point forward over any spaces and tabs. Then it
inserts after point a newline and enough indentation to reach the same
column point is on. Point remains before the inserted newline; in this
regard, C-M-o resembles C-o.
To join two lines cleanly, use the M-^
(delete-indentation) command. It deletes the indentation at the
front of the current line, and the line boundary as well, replacing them
with a single space. As a special case (useful for Lisp code) the
single space is omitted if the characters to be joined are consecutive
open parentheses or closing parentheses, or if the junction follows
another newline. To delete just the indentation of a line, go to the
beginning of the line and use M-\
(delete-horizontal-space), which deletes all spaces and tabs
around the cursor.
If you have a fill prefix, M-^ deletes the fill prefix if it appears after the newline that is deleted. See Fill Prefix.
There are also commands for changing the indentation of several lines
at once. They apply to all the lines that begin in the region.
C-M-\ (indent-region) indents each line in the “usual”
way, as if you had typed <TAB> at the beginning of the line. A
numeric argument specifies the column to indent to, and each line is
shifted left or right so that its first nonblank character appears in
that column. C-x <TAB> (indent-rigidly) moves all of
the lines in the region right by its argument (left, for negative
arguments). The whole group of lines moves rigidly sideways, which is
how the command gets its name.
If you want to remove all indentation from all of the line in the region, invoke C-x <TAB> with a large negative argument, such as -1000.
M-x indent-relative indents at point based on the previous line
(actually, the last nonempty line). It inserts whitespace at point, moving
point, until it is underneath the next indentation point in the previous line.
An indentation point is the end of a sequence of whitespace or the end of
the line. If point is farther right than any indentation point in the
previous line, indent-relative runs tab-to-tab-stop
unless it is called with a numeric argument, in which case it does
nothing.
See Format Indentation, for another way of specifying the indentation for part of your text.
For typing in tables, you can use M-i (tab-to-tab-stop).
This command inserts indentation before point, enough to reach the
next tab stop column.
You can specify the tab stops used by M-i. They are stored in a
variable called tab-stop-list, as a list of column-numbers in
increasing order.
The convenient way to set the tab stops is with M-x
edit-tab-stops, which creates and selects a buffer containing a
description of the tab stop settings. You can edit this buffer to
specify different tab stops, and then type C-c C-c to make those
new tab stops take effect. The buffer uses Overwrite mode
(see Minor Modes). edit-tab-stops records which buffer was
current when you invoked it, and stores the tab stops back in that
buffer; normally all buffers share the same tab stops and changing
them in one buffer affects all, but if you happen to make
tab-stop-list local in one buffer then edit-tab-stops in
that buffer will edit the local settings.
Here is what the text representing the tab stops looks like for ordinary tab stops every eight columns.
: : : : : :
0 1 2 3 4
0123456789012345678901234567890123456789012345678
To install changes, type C-c C-c
The first line contains a colon at each tab stop. The remaining lines are present just to help you see where the colons are and know what to do.
Note that the tab stops that control tab-to-tab-stop have nothing
to do with displaying tab characters in the buffer. See Display Custom,
for more information on that.
Emacs normally uses both tabs and spaces to indent lines. If you
prefer, all indentation can be made from spaces only. To request
this, set indent-tabs-mode to nil. This is a per-buffer
variable, so altering the variable affects only the current buffer,
but there is a default value which you can change as well.
See Locals.
A tab is not always displayed in the same way. By default, tabs are eight columns wide, but some people like to customize their tools to use a different tab width. So by using spaces only, you can make sure that your file looks the same regardless of the tab width setting.
There are also commands to convert tabs to spaces or vice versa, always preserving the columns of all nonblank text. M-x tabify scans the region for sequences of spaces, and converts sequences of at least two spaces to tabs if that can be done without changing indentation. M-x untabify changes all tabs in the region to appropriate numbers of spaces.
The term text has two widespread meanings in our area of the computer field. One is data that is a sequence of characters. Any file that you edit with Emacs is text, in this sense of the word. The other meaning is more restrictive: a sequence of characters in a human language for humans to read (possibly after processing by a text formatter), as opposed to a program or commands for a program.
Human languages have syntactic/stylistic conventions that can be supported or used to advantage by editor commands: conventions involving words, sentences, paragraphs, and capital letters. This chapter describes Emacs commands for all of these things. There are also commands for filling, which means rearranging the lines of a paragraph to be approximately equal in length. The commands for moving over and killing words, sentences and paragraphs, while intended primarily for editing text, are also often useful for editing programs.
Emacs has several major modes for editing human-language text. If the file contains text pure and simple, use Text mode, which customizes Emacs in small ways for the syntactic conventions of text. Outline mode provides special commands for operating on text with an outline structure.
For text which contains embedded commands for text formatters, Emacs has other major modes, each for a particular text formatter. Thus, for input to TeX, you would use TeX For input to nroff, use Nroff mode.
Instead of using a text formatter, you can edit formatted text in WYSIWYG style (“what you see is what you get”), with Enriched mode. Then the formatting appears on the screen in Emacs while you edit.
The “automatic typing” features may be useful when writing text. see Top.
Emacs has commands for moving over or operating on words. By convention, the keys for them are all Meta characters.
forward-word).
backward-word).
kill-word).
backward-kill-word).
mark-word).
transpose-words).
Notice how these keys form a series that parallels the character-based C-f, C-b, C-d, <DEL> and C-t. M-@ is cognate to C-@, which is an alias for C-<SPC>.
The commands M-f (forward-word) and M-b
(backward-word) move forward and backward over words. These
Meta characters are thus analogous to the corresponding control
characters, C-f and C-b, which move over single characters
in the text. The analogy extends to numeric arguments, which serve as
repeat counts. M-f with a negative argument moves backward, and
M-b with a negative argument moves forward. Forward motion
stops right after the last letter of the word, while backward motion
stops right before the first letter.
M-d (kill-word) kills the word after point. To be
precise, it kills everything from point to the place M-f would
move to. Thus, if point is in the middle of a word, M-d kills
just the part after point. If some punctuation comes between point and the
next word, it is killed along with the word. (If you wish to kill only the
next word but not the punctuation before it, simply do M-f to get
the end, and kill the word backwards with M-<DEL>.)
M-d takes arguments just like M-f.
M-<DEL> (backward-kill-word) kills the word before
point. It kills everything from point back to where M-b would
move to. If point is after the space in ‘FOO, BAR’, then
‘FOO, ’ is killed. (If you wish to kill just ‘FOO’, and
not the comma and the space, use M-b M-d instead of
M-<DEL>.)
M-t (transpose-words) exchanges the word before or
containing point with the following word. The delimiter characters between
the words do not move. For example, ‘FOO, BAR’ transposes into
‘BAR, FOO’ rather than ‘BAR FOO,’. See Transpose, for
more on transposition and on arguments to transposition commands.
To operate on the next n words with an operation which applies
between point and mark, you can either set the mark at point and then move
over the words, or you can use the command M-@ (mark-word)
which does not move point, but sets the mark where M-f would move
to. M-@ accepts a numeric argument that says how many words to
scan for the place to put the mark. In Transient Mark mode, this command
activates the mark.
The word commands' understanding of syntax is completely controlled by the syntax table. Any character can, for example, be declared to be a word delimiter. See Syntax.
The Emacs commands for manipulating sentences and paragraphs are mostly on Meta keys, so as to be like the word-handling commands.
backward-sentence).
forward-sentence).
kill-sentence).
backward-kill-sentence).
The commands M-a and M-e (backward-sentence and
forward-sentence) move to the beginning and end of the current
sentence, respectively. They were chosen to resemble C-a and
C-e, which move to the beginning and end of a line. Unlike
them, M-a and M-e move over successive sentences if
repeated.
Moving backward over a sentence places point just before the first character of the sentence; moving forward places point right after the punctuation that ends the sentence. Neither one moves over the whitespace at the sentence boundary.
Just as C-a and C-e have a kill command, C-k, to go
with them, so M-a and M-e have a corresponding kill command
M-k (kill-sentence) which kills from point to the end of
the sentence. With minus one as an argument it kills back to the
beginning of the sentence. Larger arguments serve as a repeat count.
There is also a command, C-x <DEL>
(backward-kill-sentence), for killing back to the beginning of a
sentence. This command is useful when you change your mind in the
middle of composing text.
The sentence commands assume that you follow the American typist's convention of putting two spaces at the end of a sentence; they consider a sentence to end wherever there is a ‘.’, ‘?’ or ‘!’ followed by the end of a line or two spaces, with any number of ‘)’, ‘]’, ‘'’, or ‘"’ characters allowed in between. A sentence also begins or ends wherever a paragraph begins or ends.
The variable sentence-end controls recognition of the end of
a sentence. If non-nil, it is a regexp that matches the last
few characters of a sentence, together with the whitespace following
the sentence. If the value is nil, the default, then Emacs
computes the regexp according to various criteria. The result is
normally similar to the following regexp:
"[.?!][]\"')]*\\($\\| $\\|\t\\| \\)[ \t\n]*"
This example is explained in the section on regexps. See Regexp Example.
If you want to use just one space between sentences, you should
set sentence-end to this value:
"[.?!][]\"')]*\\($\\|\t\\| \\)[ \t\n]*"
This is what setting the variable sentence-end-double-space to
nil automatically does. But note that this makes it impossible
to distinguish between periods that end sentences and those that
indicate abbreviations.
The Emacs commands for manipulating paragraphs are also Meta keys.
backward-paragraph).
forward-paragraph).
mark-paragraph).
M-{ moves to the beginning of the current or previous paragraph, while M-} moves to the end of the current or next paragraph. Blank lines and text-formatter command lines separate paragraphs and are not considered part of any paragraph. In Paragraph-Indent Text mode, but not in Text mode, an indented line also starts a new paragraph. If there is a blank line before the paragraph, M-{ moves to the blank line, because that is convenient in practice.
In major modes for programs, paragraphs begin and end only at blank lines. This makes the paragraph commands continue to be useful even though there are no paragraphs per se.
When there is a fill prefix, then paragraphs are delimited by all lines which don't start with the fill prefix. See Filling.
When you wish to operate on a paragraph, you can use the command
M-h (mark-paragraph) to set the region around it. Thus,
for example, M-h C-w kills the paragraph around or after point.
The M-h command puts point at the beginning and mark at the end of
the paragraph point was in. In Transient Mark mode, it activates the
mark. If point is between paragraphs (in a run of blank lines, or at a
boundary), the paragraph following point is surrounded by point and
mark. If there are blank lines preceding the first line of the
paragraph, one of these blank lines is included in the region.
The precise definition of a paragraph boundary is controlled by the
variables paragraph-separate and paragraph-start. The
value of paragraph-start is a regexp that should match any line
that either starts or separates paragraphs. The value of
paragraph-separate is another regexp that should match only lines
that separate paragraphs without being part of any paragraph (for
example, blank lines). Lines that start a new paragraph and are
contained in it must match only paragraph-start, not
paragraph-separate. Each regular expression must match at the
left margin. For example, in Fundamental mode, paragraph-start
is "\f\\|[ \t]*$", and paragraph-separate is
"[ \t\f]*$".
Normally it is desirable for page boundaries to separate paragraphs. The default values of these variables recognize the usual separator for pages.
Files are often thought of as divided into pages by the formfeed character (ASCII control-L, octal code 014). When you print hardcopy for a file, this character forces a page break; thus, each page of the file goes on a separate page on paper. Most Emacs commands treat the page-separator character just like any other character: you can insert it with C-q C-l, and delete it with <DEL>. Thus, you are free to paginate your file or not. However, since pages are often meaningful divisions of the file, Emacs provides commands to move over them and operate on them.
backward-page).
forward-page).
mark-page).
count-lines-page).
The C-x [ (backward-page) command moves point to immediately
after the previous page delimiter. If point is already right after a page
delimiter, it skips that one and stops at the previous one. A numeric
argument serves as a repeat count. The C-x ] (forward-page)
command moves forward past the next page delimiter.
The C-x C-p command (mark-page) puts point at the
beginning of the current page and the mark at the end. The page
delimiter at the end is included (the mark follows it). The page
delimiter at the front is excluded (point follows it). In Transient
Mark mode, this command activates the mark.
C-x C-p C-w is a handy way to kill a page to move it elsewhere. If you move to another page delimiter with C-x [ and C-x ], then yank the killed page, all the pages will be properly delimited once again. The reason C-x C-p includes only the following page delimiter in the region is to ensure that.
A numeric argument to C-x C-p is used to specify which page to go to, relative to the current one. Zero means the current page. One means the next page, and −1 means the previous one.
The C-x l command (count-lines-page) is good for deciding
where to break a page in two. It displays in the echo area the total number
of lines in the current page, and then divides it up into those preceding
the current line and those following, as in
Page has 96 (72+25) lines
Notice that the sum is off by one; this is correct if point is not at the beginning of a line.
The variable page-delimiter controls where pages begin. Its
value is a regexp that matches the beginning of a line that separates
pages. The normal value of this variable is "^\f", which
matches a formfeed character at the beginning of a line.
Filling text means breaking it up into lines that fit a specified width. Emacs does filling in two ways. In Auto Fill mode, inserting text with self-inserting characters also automatically fills it. There are also explicit fill commands that you can use when editing text leaves it unfilled. When you edit formatted text, you can specify a style of filling for each portion of the text (see Formatted Text).
Auto Fill mode is a minor mode in which lines are broken automatically when they become too wide. Breaking happens only when you type a <SPC> or <RET>.
M-x auto-fill-mode turns Auto Fill mode on if it was off, or off if it was on. With a positive numeric argument it always turns Auto Fill mode on, and with a negative argument always turns it off. You can see when Auto Fill mode is in effect by the presence of the word ‘Fill’ in the mode line, inside the parentheses. Auto Fill mode is a minor mode which is enabled or disabled for each buffer individually. See Minor Modes.
In Auto Fill mode, lines are broken automatically at spaces when they get longer than the desired width. Line breaking and rearrangement takes place only when you type <SPC> or <RET>. If you wish to insert a space or newline without permitting line-breaking, type C-q <SPC> or C-q C-j (recall that a newline is really a control-J). Also, C-o inserts a newline without line breaking.
Auto Fill mode works well with programming-language modes, because it
indents new lines with <TAB>. If a line ending in a comment gets
too long, the text of the comment is split into two comment lines.
Optionally, new comment delimiters are inserted at the end of the first
line and the beginning of the second so that each line is a separate
comment; the variable comment-multi-line controls the choice
(see Comments).
Adaptive filling (see Adaptive Fill) works for Auto Filling as well as for explicit fill commands. It takes a fill prefix automatically from the second or first line of a paragraph.
Auto Fill mode does not refill entire paragraphs; it can break lines but cannot merge lines. So editing in the middle of a paragraph can result in a paragraph that is not correctly filled. The easiest way to make the paragraph properly filled again is usually with the explicit fill commands.
Many users like Auto Fill mode and want to use it in all text files. The section on init files says how to arrange this permanently for yourself. See Init File.
Refill minor mode provides support for keeping paragraphs filled as you type or modify them in other ways. It provides an effect similar to typical word processor behavior. This works by running a paragraph-filling command at suitable times.
To toggle the use of Refill mode in the current buffer, type M-x refill-mode. When you are typing text, only characters which normally trigger auto filling, like the space character, will trigger refilling. This is to avoid making it too slow. Apart from self-inserting characters, other commands which modify the text cause refilling.
The current implementation is preliminary and not robust. You can get better “line wrapping” behavior using Longlines mode. See Longlines. However, Longlines mode has an important side-effect: the newlines that it inserts for you are not saved to disk, so the files that you make with Longlines mode will appear to be completely unfilled if you edit them without Longlines mode.
fill-paragraph).
set-fill-column).
fill-region).
To refill a paragraph, use the command M-q
(fill-paragraph). This operates on the paragraph that point is
inside, or the one after point if point is between paragraphs.
Refilling works by removing all the line-breaks, then inserting new ones
where necessary.
To refill many paragraphs, use M-x fill-region, which divides the region into paragraphs and fills each of them.
M-q and fill-region use the same criteria as M-h
for finding paragraph boundaries (see Paragraphs). For more
control, you can use M-x fill-region-as-paragraph, which refills
everything between point and mark. This command deletes any blank lines
within the region, so separate blocks of text end up combined into one
block.
A numeric argument to M-q causes it to justify the text as
well as filling it. This means that extra spaces are inserted to make
the right margin line up exactly at the fill column. To remove the
extra spaces, use M-q with no argument. (Likewise for
fill-region.) Another way to control justification, and choose
other styles of filling, is with the justification text property;
see Format Justification.
The command M-s (center-line) centers the current line
within the current fill column. With an argument n, it centers
n lines individually and moves past them. This binding is
made by Text mode and is available only in that and related modes
(see Text Mode).
The maximum line width for filling is in the variable
fill-column. Altering the value of fill-column makes it
local to the current buffer; until that time, the default value is in
effect. The default is initially 70. See Locals. The easiest way
to set fill-column is to use the command C-x f
(set-fill-column). With a numeric argument, it uses that as the
new fill column. With just C-u as argument, it sets
fill-column to the current horizontal position of point.
Emacs commands normally consider a period followed by two spaces or by a newline as the end of a sentence; a period followed by just one space indicates an abbreviation and not the end of a sentence. To preserve the distinction between these two ways of using a period, the fill commands do not break a line after a period followed by just one space.
If the variable sentence-end-double-space is nil, the
fill commands expect and leave just one space at the end of a sentence.
Ordinarily this variable is t, so the fill commands insist on
two spaces for the end of a sentence, as explained above. See Sentences.
If the variable colon-double-space is non-nil, the
fill commands put two spaces after a colon.
Some languages do not use period to indicate end of sentence. For
example, a sentence in Thai text ends with double space but without a
period. Set the variable sentence-end-without-period to
t to tell the sentence commands that a period is not necessary.
The variable fill-nobreak-predicate specifies additional
conditions for where line-breaking is allowed. Its value is either
nil or a Lisp function; the function is called with no
arguments, and if it returns a non-nil value, then point is not
a good place to break the line. Two standard functions you can use are
fill-single-word-nobreak-p (don't break after the first word of
a sentence or before the last) and fill-french-nobreak-p (don't
break after ‘(’ or before ‘)’, ‘:’ or ‘?’).
To fill a paragraph in which each line starts with a special marker (which might be a few spaces, giving an indented paragraph), you can use the fill prefix feature. The fill prefix is a string that Emacs expects every line to start with, and which is not included in filling. You can specify a fill prefix explicitly; Emacs can also deduce the fill prefix automatically (see Adaptive Fill).
set-fill-prefix).
fill-paragraph).
To specify a fill prefix for the current buffer, move to a line that
starts with the desired prefix, put point at the end of the prefix,
and give the command C-x . (set-fill-prefix).
That's a period after the C-x. To turn off the fill prefix,
specify an empty prefix: type C-x . with point at the
beginning of a line.
When a fill prefix is in effect, the fill commands remove the fill prefix from each line before filling and insert it on each line after filling. (The beginning of the first line is left unchanged, since often that is intentionally different.) Auto Fill mode also inserts the fill prefix automatically when it makes a new line. The C-o command inserts the fill prefix on new lines it creates, when you use it at the beginning of a line (see Blank Lines). Conversely, the command M-^ deletes the prefix (if it occurs) after the newline that it deletes (see Indentation).
For example, if fill-column is 40 and you set the fill prefix
to ‘;; ’, then M-q in the following text
;; This is an
;; example of a paragraph
;; inside a Lisp-style comment.
produces this:
;; This is an example of a paragraph
;; inside a Lisp-style comment.
Lines that do not start with the fill prefix are considered to start paragraphs, both in M-q and the paragraph commands; this gives good results for paragraphs with hanging indentation (every line indented except the first one). Lines which are blank or indented once the prefix is removed also separate or start paragraphs; this is what you want if you are writing multi-paragraph comments with a comment delimiter on each line.
You can use M-x fill-individual-paragraphs to set the fill prefix for each paragraph automatically. This command divides the region into paragraphs, treating every change in the amount of indentation as the start of a new paragraph, and fills each of these paragraphs. Thus, all the lines in one “paragraph” have the same amount of indentation. That indentation serves as the fill prefix for that paragraph.
M-x fill-nonuniform-paragraphs is a similar command that divides
the region into paragraphs in a different way. It considers only
paragraph-separating lines (as defined by paragraph-separate) as
starting a new paragraph. Since this means that the lines of one
paragraph may have different amounts of indentation, the fill prefix
used is the smallest amount of indentation of any of the lines of the
paragraph. This gives good results with styles that indent a paragraph's
first line more or less that the rest of the paragraph.
The fill prefix is stored in the variable fill-prefix. Its value
is a string, or nil when there is no fill prefix. This is a
per-buffer variable; altering the variable affects only the current buffer,
but there is a default value which you can change as well. See Locals.
The indentation text property provides another way to control
the amount of indentation paragraphs receive. See Format Indentation.
The fill commands can deduce the proper fill prefix for a paragraph automatically in certain cases: either whitespace or certain punctuation characters at the beginning of a line are propagated to all lines of the paragraph.
If the paragraph has two or more lines, the fill prefix is taken from the paragraph's second line, but only if it appears on the first line as well.
If a paragraph has just one line, fill commands may take a prefix from that line. The decision is complicated because there are three reasonable things to do in such a case:
All three of these styles of formatting are commonly used. So the fill commands try to determine what you would like, based on the prefix that appears and on the major mode. Here is how.
If the prefix found on the first line matches
adaptive-fill-first-line-regexp, or if it appears to be a
comment-starting sequence (this depends on the major mode), then the
prefix found is used for filling the paragraph, provided it would not
act as a paragraph starter on subsequent lines.
Otherwise, the prefix found is converted to an equivalent number of spaces, and those spaces are used as the fill prefix for the rest of the lines, provided they would not act as a paragraph starter on subsequent lines.
In Text mode, and other modes where only blank lines and page delimiters separate paragraphs, the prefix chosen by adaptive filling never acts as a paragraph starter, so it can always be used for filling.
The variable adaptive-fill-regexp determines what kinds of line
beginnings can serve as a fill prefix: any characters at the start of
the line that match this regular expression are used. If you set the
variable adaptive-fill-mode to nil, the fill prefix is
never chosen automatically.
You can specify more complex ways of choosing a fill prefix
automatically by setting the variable adaptive-fill-function to a
function. This function is called with point after the left margin of a
line, and it should return the appropriate fill prefix based on that
line. If it returns nil, adaptive-fill-regexp gets
a chance to find a prefix.
Long Lines mode is a minor mode for word wrapping; it lets you edit “unfilled” text files, which Emacs would normally display as a bunch of extremely long lines. Many text editors, such as those built into many web browsers, normally do word wrapping.
To enable Long Lines mode, type M-x longlines-mode. If the text is full of long lines, this will “wrap” them immediately—i.e., break up to fit in the window. As you edit the text, Long Lines mode automatically re-wraps lines by inserting or deleting soft newlines as necessary (see Hard and Soft Newlines.) These soft newlines won't show up when you save the buffer into a file, or when you copy the text into the kill ring, clipboard, or a register.
Word wrapping is not the same as ordinary filling (see Fill Commands). It does not contract multiple spaces into a single space, recognize fill prefixes (see Fill Prefix), or perform adaptive filling (see Adaptive Fill). The reason for this is that a wrapped line is still, conceptually, a single line. Each soft newline is equivalent to exactly one space in that long line, and vice versa. However, you can still call filling functions such as M-q, and these will work as expected, inserting soft newlines that won't show up on disk or when the text is copied. You can even rely entirely on the normal fill commands by turning off automatic line wrapping, with C-u M-x longlines-auto-wrap. To turn automatic line wrapping back on, type M-x longlines-auto-wrap.
Whenever you type RET, you are inserting a hard newline. If you want to see where all the hard newlines are, type M-x longlines-show-hard-newlines. This will mark each hard newline with a special symbol. The same command with a prefix argument turns this display off.
Long Lines mode does not change normal text files that are already
filled, since the existing newlines are considered hard newlines.
Before Long Lines can do anything, you need to transform each
paragraph into a long line. One way is to set fill-column to a
large number (e.g., C-u 9999 C-x f), re-fill all the paragraphs,
and then set fill-column back to its original value.
Emacs has commands for converting either a single word or any arbitrary range of text to upper case or to lower case.
downcase-word).
upcase-word).
capitalize-word).
downcase-region).
upcase-region).
The word conversion commands are the most useful. M-l
(downcase-word) converts the word after point to lower case, moving
past it. Thus, repeating M-l converts successive words.
M-u (upcase-word) converts to all capitals instead, while
M-c (capitalize-word) puts the first letter of the word
into upper case and the rest into lower case. All these commands convert
several words at once if given an argument. They are especially convenient
for converting a large amount of text from all upper case to mixed case,
because you can move through the text using M-l, M-u or
M-c on each word as appropriate, occasionally using M-f instead
to skip a word.
When given a negative argument, the word case conversion commands apply to the appropriate number of words before point, but do not move point. This is convenient when you have just typed a word in the wrong case: you can give the case conversion command and continue typing.
If a word case conversion command is given in the middle of a word, it
applies only to the part of the word which follows point. This is just
like what M-d (kill-word) does. With a negative argument,
case conversion applies only to the part of the word before point.
The other case conversion commands are C-x C-u
(upcase-region) and C-x C-l (downcase-region), which
convert everything between point and mark to the specified case. Point and
mark do not move.
The region case conversion commands upcase-region and
downcase-region are normally disabled. This means that they ask
for confirmation if you try to use them. When you confirm, you may
enable the command, which means it will not ask for confirmation again.
See Disabling.
When you edit files of text in a human language, it's more convenient to use Text mode rather than Fundamental mode. To enter Text mode, type M-x text-mode.
In Text mode, only blank lines and page delimiters separate paragraphs. As a result, paragraphs can be indented, and adaptive filling determines what indentation to use when filling a paragraph. See Adaptive Fill.
Text mode defines <TAB> to run indent-relative
(see Indentation), so that you can conveniently indent a line like
the previous line.
Text mode turns off the features concerned with comments except when you explicitly invoke them. It changes the syntax table so that single-quotes are considered part of words. However, if a word starts with single-quotes, then these are treated as a prefix for purposes such as capitalization. That is, M-c will convert ‘'hello'’ into ‘'Hello'’, as expected.
If you indent the first lines of paragraphs, then you should use Paragraph-Indent Text mode rather than Text mode. In this mode, you do not need to have blank lines between paragraphs, because the first-line indentation is sufficient to start a paragraph; however paragraphs in which every line is indented are not supported. Use M-x paragraph-indent-text-mode to enter this mode. Use M-x paragraph-indent-minor-mode to enter an equivalent minor mode, for instance during mail composition.
Text mode, and all the modes based on it, define M-<TAB>
as the command ispell-complete-word, which performs completion
of the partial word in the buffer before point, using the spelling
dictionary as the space of possible words. See Spelling. If your
window manager defines M-<TAB> to switch windows, you can
type <ESC> <TAB> or C-M-i.
Entering Text mode runs the hook text-mode-hook. Other major
modes related to Text mode also run this hook, followed by hooks of
their own; this includes Paragraph-Indent Text mode, Nroff mode, TeX
mode, Outline mode, and Mail mode. Hook functions on
text-mode-hook can look at the value of major-mode to see
which of these modes is actually being entered. See Hooks.
Outline mode is a major mode much like Text mode but intended for editing outlines. It allows you to make parts of the text temporarily invisible so that you can see the outline structure. Type M-x outline-mode to switch to Outline mode as the major mode of the current buffer.
When Outline mode makes a line invisible, the line does not appear on the screen. The screen appears exactly as if the invisible line were deleted, except that an ellipsis (three periods in a row) appears at the end of the previous visible line. (Multiple consecutive invisible lines produce just one ellipsis.)
Editing commands that operate on lines, such as C-n and C-p, treat the text of the invisible line as part of the previous visible line. Killing the ellipsis at the end of a visible line really kills all the following invisible lines.
Outline minor mode provides the same commands as the major mode, Outline mode, but you can use it in conjunction with other major modes. Type M-x outline-minor-mode to enable the Outline minor mode in the current buffer. You can also specify this in the text of a file, with a file local variable of the form ‘mode: outline-minor’ (see File Variables).
The major mode, Outline mode, provides special key bindings on the
C-c prefix. Outline minor mode provides similar bindings with
C-c @ as the prefix; this is to reduce the conflicts with the
major mode's special commands. (The variable
outline-minor-mode-prefix controls the prefix used.)
Entering Outline mode runs the hook text-mode-hook followed by
the hook outline-mode-hook (see Hooks).
Outline mode assumes that the lines in the buffer are of two types: heading lines and body lines. A heading line represents a topic in the outline. Heading lines start with one or more stars; the number of stars determines the depth of the heading in the outline structure. Thus, a heading line with one star is a major topic; all the heading lines with two stars between it and the next one-star heading are its subtopics; and so on. Any line that is not a heading line is a body line. Body lines belong with the preceding heading line. Here is an example:
* Food
This is the body,
which says something about the topic of food.
** Delicious Food
This is the body of the second-level header.
** Distasteful Food
This could have
a body too, with
several lines.
*** Dormitory Food
* Shelter
Another first-level topic with its header line.
A heading line together with all following body lines is called collectively an entry. A heading line together with all following deeper heading lines and their body lines is called a subtree.
You can customize the criterion for distinguishing heading lines
by setting the variable outline-regexp. Any line whose
beginning has a match for this regexp is considered a heading line.
Matches that start within a line (not at the left margin) do not count.
The length of the matching text determines the level of the heading;
longer matches make a more deeply nested level. Thus, for example,
if a text formatter has commands ‘@chapter’, ‘@section’
and ‘@subsection’ to divide the document into chapters and
sections, you could make those lines count as heading lines by
setting outline-regexp to ‘"@chap\\|@\\(sub\\)*section"’.
Note the trick: the two words ‘chapter’ and ‘section’ are equally
long, but by defining the regexp to match only ‘chap’ we ensure
that the length of the text matched on a chapter heading is shorter,
so that Outline mode will know that sections are contained in chapters.
This works as long as no other command starts with ‘@chap’.
You can change the rule for calculating the level of a heading line
by setting the variable outline-level. The value of
outline-level should be a function that takes no arguments and
returns the level of the current heading. Some major modes such as C,
Nroff, and Emacs Lisp mode set this variable and outline-regexp
in order to work with Outline minor mode.
Outline mode provides special motion commands that move backward and forward to heading lines.
outline-next-visible-heading).
outline-previous-visible-heading).
outline-forward-same-level).
outline-backward-same-level).
outline-up-heading).
C-c C-n (outline-next-visible-heading) moves down to the next
heading line. C-c C-p (outline-previous-visible-heading) moves
similarly backward. Both accept numeric arguments as repeat counts. The
names emphasize that invisible headings are skipped, but this is not really
a special feature. All editing commands that look for lines ignore the
invisible lines automatically.
More powerful motion commands understand the level structure of headings.
C-c C-f (outline-forward-same-level) and
C-c C-b (outline-backward-same-level) move from one
heading line to another visible heading at the same depth in
the outline. C-c C-u (outline-up-heading) moves
backward to another heading that is less deeply nested.
The other special commands of outline mode are used to make lines visible
or invisible. Their names all start with hide or show.
Most of them fall into pairs of opposites. They are not undoable; instead,
you can undo right past them. Making lines visible or invisible is simply
not recorded by the undo mechanism.
Many of these commands act on the “current” heading line. If point is on a heading line, that is the current heading line; if point is on a body line, the current heading line is the nearest preceding header line.
hide-entry).
show-entry).
hide-subtree).
show-subtree).
hide-leaves).
show-branches).
show-children).
hide-body).
show-all).
hide-sublevels).
hide-other).
Two commands that are exact opposites are C-c C-c
(hide-entry) and C-c C-e (show-entry). They apply
to the body lines directly following the current heading line.
Subheadings and their bodies are not affected.
Two more powerful opposites are C-c C-d (hide-subtree)
and C-c C-s (show-subtree). Both apply to the current
heading line's subtree: its body, all its subheadings, both
direct and indirect, and all of their bodies. In other words, the
subtree contains everything following the current heading line, up to
and not including the next heading of the same or higher rank.
Intermediate between a visible subtree and an invisible one is having
all the subheadings visible but none of the body. There are two
commands for doing this, depending on whether you want to hide the
bodies or make the subheadings visible. They are C-c C-l
(hide-leaves) and C-c C-k (show-branches).
A little weaker than show-branches is C-c C-i
(show-children). It makes just the direct subheadings
visible—those one level down. Deeper subheadings remain invisible, if
they were invisible.
Two commands have a blanket effect on the whole file. C-c C-t
(hide-body) makes all body lines invisible, so that you see just
the outline structure (as a special exception, it will not hide lines
at the top of the file, preceding the first header line, even though
these are technically body lines). C-c C-a (show-all)
makes all lines visible. These commands can be thought of as a pair
of opposites even though C-c C-a applies to more than just body
lines.
The command C-c C-q (hide-sublevels) hides all but the
top level headings. With a numeric argument n, it hides everything
except the top n levels of heading lines.
The command C-c C-o (hide-other) hides everything except
the heading and body text that point is in, plus its parents (the headers
leading up from there to top level in the outline) and the top level
headings.
When incremental search finds text that is hidden by Outline mode, it makes that part of the buffer visible. If you exit the search at that position, the text remains visible. You can also automatically make text visible as you navigate in it by using M-x reveal-mode.
You can display two views of a single outline at the same time, in different windows. To do this, you must create an indirect buffer using M-x make-indirect-buffer. The first argument of this command is the existing outline buffer name, and its second argument is the name to use for the new indirect buffer. See Indirect Buffers.
Once the indirect buffer exists, you can display it in a window in the normal fashion, with C-x 4 b or other Emacs commands. The Outline mode commands to show and hide parts of the text operate on each buffer independently; as a result, each buffer can have its own view. If you want more than two views on the same outline, create additional indirect buffers.
The Foldout package extends Outline mode and Outline minor mode with “folding” commands. The idea of folding is that you zoom in on a nested portion of the outline, while hiding its relatives at higher levels.
Consider an Outline mode buffer with all the text and subheadings under level-1 headings hidden. To look at what is hidden under one of these headings, you could use C-c C-e (M-x show-entry) to expose the body, or C-c C-i to expose the child (level-2) headings.
With Foldout, you use C-c C-z (M-x foldout-zoom-subtree). This exposes the body and child subheadings, and narrows the buffer so that only the level-1 heading, the body and the level-2 headings are visible. Now to look under one of the level-2 headings, position the cursor on it and use C-c C-z again. This exposes the level-2 body and its level-3 child subheadings and narrows the buffer again. Zooming in on successive subheadings can be done as much as you like. A string in the mode line shows how deep you've gone.
When zooming in on a heading, to see only the child subheadings specify a numeric argument: C-u C-c C-z. The number of levels of children can be specified too (compare M-x show-children), e.g. M-2 C-c C-z exposes two levels of child subheadings. Alternatively, the body can be specified with a negative argument: M-- C-c C-z. The whole subtree can be expanded, similarly to C-c C-s (M-x show-subtree), by specifying a zero argument: M-0 C-c C-z.
While you're zoomed in, you can still use Outline mode's exposure and hiding functions without disturbing Foldout. Also, since the buffer is narrowed, “global” editing actions will only affect text under the zoomed-in heading. This is useful for restricting changes to a particular chapter or section of your document.
To unzoom (exit) a fold, use C-c C-x (M-x foldout-exit-fold). This hides all the text and subheadings under the top-level heading and returns you to the previous view of the buffer. Specifying a numeric argument exits that many levels of folds. Specifying a zero argument exits all folds.
To cancel the narrowing of a fold without hiding the text and subheadings, specify a negative argument. For example, M--2 C-c C-x exits two folds and leaves the text and subheadings exposed.
Foldout mode also provides mouse commands for entering and exiting folds, and for showing and hiding text:
You can specify different modifier keys (instead of
Control-Meta-) by setting foldout-mouse-modifiers; but if
you have already loaded the foldout.el library, you must reload
it in order for this to take effect.
To use the Foldout package, you can type M-x load-library <RET> foldout <RET>; or you can arrange for to do that automatically by putting this in your .emacs file:
(eval-after-load "outline" '(require 'foldout))
TeX is a powerful text formatter written by Donald Knuth; it is also free, like GNU Emacs. LaTeX is a simplified input format for TeX, implemented by TeX macros; it comes with TeX. SliTeX is a special form of LaTeX.11 DocTeX (.dtx) is a special file format in which the LaTeX sources are written, combining sources with documentation.
Emacs has a special TeX mode for editing TeX input files. It provides facilities for checking the balance of delimiters and for invoking TeX on all or part of the file.
TeX mode has four variants: Plain TeX mode, LaTeX mode,
SliTeX mode, and DocTeX mode (these distinct major modes differ
only slightly). They are designed for editing the four different
formats. The command M-x tex-mode looks at the contents of the
buffer to determine whether the contents appear to be either LaTeX
input, SliTeX, or DocTeX input; if so, it selects the
appropriate mode. If the file contents do not appear to be LaTeX,
SliTeX or DocTeX, it selects Plain TeX mode. If the contents
are insufficient to determine this, the variable
tex-default-mode controls which mode is used.
When M-x tex-mode does not guess right, you can use the commands M-x plain-tex-mode, M-x latex-mode, M-x slitex-mode, and doctex-mode to select explicitly the particular variants of TeX mode.
Here are the special commands provided in TeX mode for editing the text of the file.
tex-insert-quote).
tex-terminate-paragraph).
tex-insert-braces).
up-list).
In TeX, the character ‘"’ is not normally used; we use
‘``’ to start a quotation and ‘''’ to end one. To make
editing easier under this formatting convention, TeX mode overrides
the normal meaning of the key " with a command that inserts a pair
of single-quotes or backquotes (tex-insert-quote). To be
precise, this command inserts ‘``’ after whitespace or an open
brace, ‘"’ after a backslash, and ‘''’ after any other
character.
If you need the character ‘"’ itself in unusual contexts, use C-q to insert it. Also, " with a numeric argument always inserts that number of ‘"’ characters. You can turn off the feature of " expansion by eliminating that binding in the local map (see Key Bindings).
In TeX mode, ‘$’ has a special syntax code which attempts to understand the way TeX math mode delimiters match. When you insert a ‘$’ that is meant to exit math mode, the position of the matching ‘$’ that entered math mode is displayed for a second. This is the same feature that displays the open brace that matches a close brace that is inserted. However, there is no way to tell whether a ‘$’ enters math mode or leaves it; so when you insert a ‘$’ that enters math mode, the previous ‘$’ position is shown as if it were a match, even though they are actually unrelated.
TeX uses braces as delimiters that must match. Some users prefer
to keep braces balanced at all times, rather than inserting them
singly. Use C-c { (tex-insert-braces) to insert a pair of
braces. It leaves point between the two braces so you can insert the
text that belongs inside. Afterward, use the command C-c }
(up-list) to move forward past the close brace.
There are two commands for checking the matching of braces. C-j
(tex-terminate-paragraph) checks the paragraph before point, and
inserts two newlines to start a new paragraph. It outputs a message in
the echo area if any mismatch is found. M-x tex-validate-region
checks a region, paragraph by paragraph. The errors are listed in the
‘*Occur*’ buffer, and you can use C-c C-c or Mouse-2 in
that buffer to go to a particular mismatch.
Note that Emacs commands count square brackets and parentheses in TeX mode, not just braces. This is not strictly correct for the purpose of checking TeX syntax. However, parentheses and square brackets are likely to be used in text as matching delimiters and it is useful for the various motion commands and automatic match display to work with them.
LaTeX mode, and its variant, SliTeX mode, provide a few extra features not applicable to plain TeX.
tex-latex-block).
tex-close-latex-block).
In LaTeX input, ‘\begin’ and ‘\end’ commands are used to
group blocks of text. To insert a ‘\begin’ and a matching
‘\end’ (on a new line following the ‘\begin’), use C-c
C-o (tex-latex-block). A blank line is inserted between the
two, and point is left there. You can use completion when you enter the
block type; to specify additional block type names beyond the standard
list, set the variable latex-block-names. For example, here's
how to add ‘theorem’, ‘corollary’, and ‘proof’:
(setq latex-block-names '("theorem" "corollary" "proof"))
In LaTeX input, ‘\begin’ and ‘\end’ commands must
balance. You can use C-c C-e (tex-close-latex-block) to
insert automatically a matching ‘\end’ to match the last unmatched
‘\begin’. It indents the ‘\end’ to match the corresponding
‘\begin’. It inserts a newline after ‘\end’ if point is at
the beginning of a line.
You can invoke TeX as an inferior of Emacs on either the entire contents of the buffer or just a region at a time. Running TeX in this way on just one chapter is a good way to see what your changes look like without taking the time to format the entire file.
tex-region).
tex-buffer).
tex-bibtex-file).
tex-file).
tex-recenter-output-buffer).
tex-kill-job).
tex-print).
tex-view).
tex-show-print-queue).
tex-compile).
You can pass the current buffer through an inferior TeX by means of
C-c C-b (tex-buffer). The formatted output appears in a
temporary file; to print it, type C-c C-p (tex-print).
Afterward, you can use C-c C-q (tex-show-print-queue) to
view the progress of your output towards being printed. If your terminal
has the ability to display TeX output files, you can preview the
output on the terminal with C-c C-v (tex-view).
You can specify the directory to use for running TeX by setting the
variable tex-directory. "." is the default value. If
your environment variable TEXINPUTS contains relative directory
names, or if your files contains ‘\input’ commands with relative
file names, then tex-directory must be "." or you
will get the wrong results. Otherwise, it is safe to specify some other
directory, such as "/tmp".
If you want to specify which shell commands are used in the inferior TeX,
you can do so by setting the values of the variables tex-run-command,
latex-run-command, slitex-run-command,
tex-dvi-print-command, tex-dvi-view-command, and
tex-show-queue-command. You must set the value of
tex-dvi-view-command for your particular terminal; this variable
has no default value. The other variables have default values that may
(or may not) be appropriate for your system.
Normally, the file name given to these commands comes at the end of the command string; for example, ‘latex filename’. In some cases, however, the file name needs to be embedded in the command; an example is when you need to provide the file name as an argument to one command whose output is piped to another. You can specify where to put the file name with ‘*’ in the command string. For example,
(setq tex-dvi-print-command "dvips -f * | lpr")
The terminal output from TeX, including any error messages, appears in a buffer called ‘*tex-shell*’. If TeX gets an error, you can switch to this buffer and feed it input (this works as in Shell mode; see Interactive Shell). Without switching to this buffer you can scroll it so that its last line is visible by typing C-c C-l.
Type C-c C-k (tex-kill-job) to kill the TeX process if
you see that its output is no longer useful. Using C-c C-b or
C-c C-r also kills any TeX process still running.
You can also pass an arbitrary region through an inferior TeX by typing
C-c C-r (tex-region). This is tricky, however, because most files
of TeX input contain commands at the beginning to set parameters and
define macros, without which no later part of the file will format
correctly. To solve this problem, C-c C-r allows you to designate a
part of the file as containing essential commands; it is included before
the specified region as part of the input to TeX. The designated part
of the file is called the header.
To indicate the bounds of the header in Plain TeX mode, you insert two special strings in the file. Insert ‘%**start of header’ before the header, and ‘%**end of header’ after it. Each string must appear entirely on one line, but there may be other text on the line before or after. The lines containing the two strings are included in the header. If ‘%**start of header’ does not appear within the first 100 lines of the buffer, C-c C-r assumes that there is no header.
In LaTeX mode, the header begins with ‘\documentclass’ or ‘\documentstyle’ and ends with ‘\begin{document}’. These are commands that LaTeX requires you to use in any case, so nothing special needs to be done to identify the header.
The commands (tex-buffer) and (tex-region) do all of their
work in a temporary directory, and do not have available any of the auxiliary
files needed by TeX for cross-references; these commands are generally
not suitable for running the final copy in which all of the cross-references
need to be correct.
When you want the auxiliary files for cross references, use C-c
C-f (tex-file) which runs TeX on the current buffer's file,
in that file's directory. Before running TeX, it offers to save any
modified buffers. Generally, you need to use (tex-file) twice to
get the cross-references right.
The value of the variable tex-start-options specifies
options for the TeX run.
The value of the variable tex-start-commands specifies TeX
commands for starting TeX. The default value causes TeX to run
in nonstop mode. To run TeX interactively, set the variable to
"".
Large TeX documents are often split into several files—one main
file, plus subfiles. Running TeX on a subfile typically does not
work; you have to run it on the main file. In order to make
tex-file useful when you are editing a subfile, you can set the
variable tex-main-file to the name of the main file. Then
tex-file runs TeX on that file.
The most convenient way to use tex-main-file is to specify it
in a local variable list in each of the subfiles. See File Variables.
For LaTeX files, you can use BibTeX to process the auxiliary
file for the current buffer's file. BibTeX looks up bibliographic
citations in a data base and prepares the cited references for the
bibliography section. The command C-c TAB
(tex-bibtex-file) runs the shell command
(tex-bibtex-command) to produce a ‘.bbl’ file for the
current buffer's file. Generally, you need to do C-c C-f
(tex-file) once to generate the ‘.aux’ file, then do
C-c TAB (tex-bibtex-file), and then repeat C-c C-f
(tex-file) twice more to get the cross-references correct.
To invoke some other compilation program on the current TeX
buffer, type C-c C-c (tex-compile). This command knows
how to pass arguments to many common programs, including
pdflatex, yap, xdvi, and dvips. You can
select your desired compilation program using the standard completion
keys (see Completion).
Entering any variant of TeX mode runs the hooks
text-mode-hook and tex-mode-hook. Then it runs either
plain-tex-mode-hook, latex-mode-hook, or
slitex-mode-hook, whichever is appropriate. Starting the
TeX shell runs the hook tex-shell-hook. See Hooks.
The commands M-x iso-iso2tex, M-x iso-tex2iso, M-x iso-iso2gtex and M-x iso-gtex2iso can be used to convert between Latin-1 encoded files and TeX-encoded equivalents.
For managing all kinds of references for LaTeX, you can use RefTeX. see Top.
The major modes for SGML and HTML include indentation support and commands to operate on tags. This section describes the special commands of these modes. (HTML mode is a slightly customized variant of SGML mode.)
sgml-tag).
This command asks you for a tag name and for the attribute values,
then inserts both the opening tag and the closing tag, leaving point
between them.
With a prefix argument n, the command puts the tag around the
n words already present in the buffer after point. With
−1 as argument, it puts the tag around the region. (In
Transient Mark mode, it does this whenever a region is active.)
sgml-attributes).
sgml-skip-tag-forward).
A numeric argument acts as a repeat count.
sgml-skip-tag-forward). A numeric argument acts as a repeat
count.
sgml-delete-tag). If the tag at or after point is an opening
tag, delete the closing tag too; if it is a closing tag, delete the
opening tag too.
sgml-tag-help). If the argument tag is empty, describe
the tag at point.
sgml-close-tag). If called from within a tag or a comment,
close this element instead of inserting a close tag.
sgml-name-8bit-mode).
sgml-validate).
SGML mode and HTML mode support XML also. In XML, every opening tag
must have an explicit closing tag. When sgml-xml-mode is
non-nil, SGML mode (and HTML mode) always insert explicit
closing tags. When you visit a file, these modes determine from the
file contents whether it is XML or not, and set sgml-xml-mode
accordingly, so that they do the right thing for the file in either
case.
Nroff mode is a mode like Text mode but modified to handle nroff commands present in the text. Invoke M-x nroff-mode to enter this mode. It differs from Text mode in only a few ways. All nroff command lines are considered paragraph separators, so that filling will never garble the nroff commands. Pages are separated by ‘.bp’ commands. Comments start with backslash-doublequote. Also, three special commands are provided that are not in Text mode:
forward-text-line). An argument is a repeat count.
backward-text-line).
count-text-lines).
The other feature of Nroff mode is that you can turn on Electric Nroff mode. This is a minor mode that you can turn on or off with M-x electric-nroff-mode (see Minor Modes). When the mode is on, each time you use <RET> to end a line that contains an nroff command that opens a kind of grouping, the matching nroff command to close that grouping is automatically inserted on the following line. For example, if you are at the beginning of a line and type . ( b <RET>, this inserts the matching command ‘.)b’ on a new line following point.
If you use Outline minor mode with Nroff mode (see Outline Mode), heading lines are lines of the form ‘.H’ followed by a number (the header level).
Entering Nroff mode runs the hook text-mode-hook, followed by
the hook nroff-mode-hook (see Hooks).
Enriched mode is a minor mode for editing files that contain formatted text in WYSIWYG fashion, as in a word processor. Currently, formatted text in Enriched mode can specify fonts, colors, underlining, margins, and types of filling and justification. In the future, we plan to implement other formatting features as well.
Enriched mode is a minor mode (see Minor Modes). It is typically used in conjunction with Text mode (see Text Mode), but you can also use it with other major modes such as Outline mode and Paragraph-Indent Text mode.
Potentially, Emacs can store formatted text files in various file formats. Currently, only one format is implemented: text/enriched format, which is defined by the MIME protocol. See Format Conversion, for details of how Emacs recognizes and converts file formats.
The Emacs distribution contains a formatted text file that can serve as an example. Its name is etc/enriched.doc. It contains samples illustrating all the features described in this section. It also contains a list of ideas for future enhancements.
Whenever you visit a file that Emacs saved in the text/enriched format, Emacs automatically converts the formatting information in the file into Emacs's own internal format (known as text properties), and turns on Enriched mode.
To create a new file of formatted text, first visit the nonexistent file, then type M-x enriched-mode before you start inserting text. This command turns on Enriched mode. Do this before you begin inserting text, to ensure that the text you insert is handled properly.
More generally, the command enriched-mode turns Enriched mode
on if it was off, and off if it was on. With a prefix argument, this
command turns Enriched mode on if the argument is positive, and turns
the mode off otherwise.
When you save a buffer while Enriched mode is enabled in it, Emacs automatically converts the text to text/enriched format while writing it into the file. When you visit the file again, Emacs will automatically recognize the format, reconvert the text, and turn on Enriched mode again.
You can add annotations for saving additional text properties, which
Emacs normally does not save, by adding to enriched-translations.
Note that the text/enriched standard requires any non-standard
annotations to have names starting with ‘x-’, as in
‘x-read-only’. This ensures that they will not conflict with
standard annotations that may be added later.
See Text Properties, for more information about text properties.
In formatted text, Emacs distinguishes between two different kinds of
newlines, hard newlines and soft newlines. (You can enable
or disable this feature separately in any buffer with the command
use-hard-newlines.)
Hard newlines are used to separate paragraphs, or items in a list, or
anywhere that there should always be a line break regardless of the
margins. The <RET> command (newline) and C-o
(open-line) insert hard newlines.
Soft newlines are used to make text fit between the margins. All the fill commands, including Auto Fill, insert soft newlines—and they delete only soft newlines.
Although hard and soft newlines look the same, it is important to bear the difference in mind. Do not use <RET> to break lines in the middle of filled paragraphs, or else you will get hard newlines that are barriers to further filling. Instead, let Auto Fill mode break lines, so that if the text or the margins change, Emacs can refill the lines properly. See Auto Fill.
On the other hand, in tables and lists, where the lines should always
remain as you type them, you can use <RET> to end lines. For these
lines, you may also want to set the justification style to
unfilled. See Format Justification.
There are two ways to alter the formatting information for a formatted text file: with keyboard commands, and with the mouse.
The easiest way to add properties to your document is with the Text Properties menu. You can get to this menu in two ways: from the Edit menu in the menu bar (use <F10> e t if you have no mouse), or with C-Mouse-2 (hold the <CTRL> key and press the middle mouse button). There are also keyboard commands described in the following section.
Most of the items in the Text Properties menu lead to other submenus. These are described in the sections that follow. Some items run commands directly:
Remove Face Propertiesfacemenu-remove-face-props).
Remove Text Propertiesfacemenu-remove-all).
Describe Propertiesdescribe-text-properties).
Display Faceslist-faces-display).
Display Colorslist-colors-display).
The Faces submenu lists various Emacs faces including bold,
italic, and underline. Selecting one of these adds the
chosen face to the region. See Faces. You can also specify a face
with these keyboard commands:
default face
(facemenu-set-default).
bold face
(facemenu-set-bold).
italic face
(facemenu-set-italic).
bold-italic face
(facemenu-set-bold-italic).
underline face
(facemenu-set-underline).
facemenu-set-face).
If you use these commands with a prefix argument—or, in Transient Mark mode, if the region is not active—then these commands specify a face to use for any immediately following self-inserting input. See Transient Mark. This applies to both the keyboard commands and the menu commands.
Specifying the default face also resets foreground and
background color to their defaults.(see Format Colors).
Any self-inserting character you type inherits, by default, the face properties (as well as most other text properties) of the preceding character. Specifying any face property, including foreground or background color, for your next self-inserting character will prevent it from inheriting any face properties from the preceding character, although it will still inherit other text properties. Characters inserted by yanking do not inherit text properties.
Enriched mode defines two additional faces: excerpt and
fixed. These correspond to codes used in the text/enriched file
format.
The excerpt face is intended for quotations. This face is the
same as italic unless you customize it (see Face Customization).
The fixed face means, “Use a fixed-width font for this part
of the text.” Applying the fixed face to a part of the text
will cause that part of the text to appear in a fixed-width font, even
if the default font is variable-width. This applies to Emacs and to
other systems that display text/enriched format. So if you
specifically want a certain part of the text to use a fixed-width
font, you should specify the fixed face for that part.
By default, the fixed face looks the same as bold.
This is an attempt to distinguish it from default. You may
wish to customize fixed to some other fixed-width medium font.
See Face Customization.
If your terminal cannot display different faces, you will not be able to see them, but you can still edit documents containing faces, and even add faces and colors to documents. The faces you specify will be visible when the file is viewed on a terminal that can display them.
You can specify foreground and background colors for portions of the text. There is a menu for specifying the foreground color and a menu for specifying the background color. Each color menu lists all the colors that you have used in Enriched mode in the current Emacs session.
If you specify a color with a prefix argument—or, in Transient Mark mode, if the region is not active—then it applies to any immediately following self-inserting input. See Transient Mark. Otherwise, the command applies to the region.
Each color menu contains one additional item: ‘Other’. You can use this item to specify a color that is not listed in the menu; it reads the color name with the minibuffer. To display a list of available colors and their names, use the ‘Display Colors’ menu item in the Text Properties menu (see Editing Format Info).
Any color that you specify in this way, or that is mentioned in a formatted text file that you read in, is added to the corresponding color menu for the duration of the Emacs session.
There are no key bindings for specifying colors, but you can do so with the extended commands M-x facemenu-set-foreground and M-x facemenu-set-background. Both of these commands read the name of the color with the minibuffer.
When editing formatted text, you can specify different amounts of indentation for the right or left margin of an entire paragraph or a part of a paragraph. The margins you specify automatically affect the Emacs fill commands (see Filling) and line-breaking commands.
The Indentation submenu provides a convenient interface for specifying these properties. The submenu contains four items:
Indent Moreincrease-left-margin). In
Enriched mode, this command is also available on C-x <TAB>; if
you supply a numeric argument, that says how many columns to add to the
margin (a negative argument reduces the number of columns).
Indent LessIndent Right MoreIndent Right LessYou can use these commands repeatedly to increase or decrease the indentation.
The most common way to use them is to change the indentation of an entire paragraph. For other uses, the effects of refilling can be hard to predict, except in some special cases like the one described next.
The most common other use is to format paragraphs with hanging indents, which means that the first line is indented less than subsequent lines. To set up a hanging indent, increase the indentation of the region starting after the first word of the paragraph and running until the end of the paragraph.
Indenting the first line of a paragraph is easier. Set the margin for the whole paragraph where you want it to be for the body of the paragraph, then indent the first line by inserting extra spaces or tabs.
The variable standard-indent specifies how many columns these
commands should add to or subtract from the indentation. The default
value is 4. The overall default right margin for Enriched mode is
controlled by the variable fill-column, as usual.
There are also two commands for setting the left or right margin of
the region absolutely: set-left-margin and
set-right-margin. Enriched mode binds these commands to
C-c [ and C-c ], respectively. You can specify the
margin width either with a numeric argument or in the minibuffer.
Sometimes, as a result of editing, the filling of a paragraph becomes
messed up—parts of the paragraph may extend past the left or right
margins. When this happens, use M-q (fill-paragraph) to
refill the paragraph.
The fill prefix, if any, works in addition to the specified paragraph indentation: C-x . does not include the specified indentation's whitespace in the new value for the fill prefix, and the fill commands look for the fill prefix after the indentation on each line. See Fill Prefix.
When editing formatted text, you can specify various styles of justification for a paragraph. The style you specify automatically affects the Emacs fill commands.
The Justification submenu provides a convenient interface for specifying the style. The submenu contains five items:
LeftRightFullCenterUnfilledIn Enriched mode, you can also specify justification from the keyboard using the M-j prefix character:
set-justification-left).
set-justification-right).
set-justification-full).
set-justification-center).
set-justification-none).
Justification styles apply to entire paragraphs. All the justification-changing commands operate on the paragraph containing point, or, if the region is active, on all paragraphs which overlap the region.
The default justification style is specified by the variable
default-justification. Its value should be one of the symbols
left, right, full, center, or none.
This is a per-buffer variable. Setting the variable directly affects
only the current buffer. However, customizing it in a Custom buffer
sets (as always) the default value for buffers that do not override it.
See Locals, and Easy Customization.
The Special Properties menu lets you add or remove three other useful text
properties: read-only, invisible and intangible.
The intangible property disallows moving point within the text,
the invisible text property hides text from display, and the
read-only property disallows alteration of the text.
Each of these special properties has a menu item to add it to the region. The last menu item, ‘Remove Special’, removes all of these special properties from the text in the region.
Currently, the invisible and intangible properties are
not saved in the text/enriched format. The read-only
property is saved, but it is not a standard part of the text/enriched
format, so other editors may not respect it.
Normally, Emacs knows when you are editing formatted text because it recognizes the special annotations used in the file that you visited. However, there are situations in which you must take special actions to convert file contents or turn on Enriched mode:
The command format-decode-buffer translates text in various
formats into Emacs's internal format. It asks you to specify the format
to translate from; however, normally you can type just <RET>, which
tells Emacs to guess the format.
If you wish to look at a text/enriched file in its raw form, as a
sequence of characters rather than as formatted text, use the M-x
find-file-literally command. This visits a file, like
find-file, but does not do format conversion. It also inhibits
character code conversion (see Coding Systems) and automatic
uncompression (see Compressed Files). To disable format conversion
but allow character code conversion and/or automatic uncompression if
appropriate, use format-find-file with suitable arguments.
Table Mode provides an easy and intuitive way to create and edit WYSIWYG text-based tables. Here is an example of such a table:
+-----------------+--------------------------------+-----------------+
| Command | Description | Key Binding |
+-----------------+--------------------------------+-----------------+
| forward-char |Move point right N characters | C-f |
| |(left if N is negative). | |
| | | |
| |On reaching end of buffer, stop | |
| |and signal error. | |
+-----------------+--------------------------------+-----------------+
| backward-char |Move point left N characters | C-b |
| |(right if N is negative). | |
| | | |
| |On attempt to pass beginning or | |
| |end of buffer, stop and signal | |
| |error. | |
+-----------------+--------------------------------+-----------------+
Table Mode allows the contents of the table such as this one to be easily manipulated by inserting or deleting characters inside a cell. A cell is effectively a localized rectangular edit region and edits to a cell do not affect the contents of the surrounding cells. If the contents do not fit into a cell, then the cell is automatically expanded in the vertical and/or horizontal directions and the rest of the table is restructured and reformatted in accordance with the growth of the cell.
Look at the following examples of valid tables as a reference while you read this section:
+--+----+---+ +-+ +--+-----+
| | | | | | | | |
+--+----+---+ +-+ | +--+--+
| | | | | | | |
+--+----+---+ +--+--+ |
| | |
+-----+--+
A table consists of a rectangular frame and the contents inside the frame. A table's cells must be at least one character wide and one character high with two adjacent cells sharing a boarder line. A cell can be subdivided into multiple rectangular cells but cannot nest or overlap.
Both the table frame and cell border lines must consist of one of three special characters. The variables that hold these characters are described below:
table-cell-vertical-chartable-cell-horizontal-chartable-cell-intersection-charBased on this definition, the following five tables are examples of invalid tables:
+-----+ +-----+ +--+ +-++--+ ++
| | | | | | | || | ++
| +-+ | | | | | | || |
| | | | +--+ | +--+--+ +-++--+
| +-+ | | | | | | | +-++--+
| | | | | | | | | || |
+-----+ +--+--+ +--+--+ +-++--+
a b c d e
From left to right:
The command to create a table is table-insert. When called
interactively, it asks for the number of columns, number of rows, cell
width and cell height. The number of columns is a number of cells
within the table's width. The number of rows is the number of cells
within the table's height. The cell width is a number of characters
that fit within a cell width. The cell height is a number of lines
within cell height. While the number of columns and number of rows
must be an integer number, the cell width and the cell height can be
either an integer number (when the value is constant across the table)
or a series of integer numbers, separated by spaces or commas, where
each number corresponds to each cell width within a row from left to
right or each cell height within a column from top to bottom.
Table Mode maintains special text properties in the buffer to allow
editing in a convenient fashion. When a buffer with tables is saved
to its file, these text properties are lost, so when you visit this
file again later, Emacs does not see a table, but just formatted text.
To resurrect the table text properties, issue the M-x
table-recognize command. It scans the current buffer, recognizes
valid table cells, and attaches appropriate text properties to allow
for table editing. The converse command, table-unrecognize, is
used to remove the special text properties and revert the buffer back
to plain text.
An optional numeric prefix argument can precede the
table-recognize command. If the argument is negative, tables
in the buffer become inactive. This is equivalent to invoking
table-unrecognize.
Similar functions exist to enable or disable tables within a region, enable or disable individual tables, and enable/disable individual cells. These commands are:
For another way of converting text into tables, see Table Conversion.
The commands table-forward-cell and
table-backward-cell move point from the current cell to an
adjacent cell forward and backward respectively. The order of the
cell is wrapped. When point is positioned in the last cell of a
table, typing M-x table-forward-cell moves point to the first
cell in the table. Likewise M-x table-backward-cell from the
first cell in a table moves point to the last cell in the table.
The command table-span-cell spans the current cell into one
of the four directions—right, left, above or below—and merges the
current cell with the adjacent cell. It does not allow directions to
which spanning does not produce a legitimate cell.
The command table-split-cell splits the current cell
vertically or horizontally. This command is a wrapper to the
direction specific commands table-split-cell-vertically and
table-split-cell-horizontally.
The command table-split-cell-vertically splits the current
cell vertically and creates a pair of cells above and below where
point is located. The content in the original cell is split as well.
The command table-split-cell-horizontally splits the current
cell horizontally and creates a pair of cells right and left of where
point is located. If the subject cell to split is not empty the user
is asked how to handle the cell contents. The three options are:
split, left, or right. split splits the
contents at point literally while the left and right
options move the entire contents into the left or right cell
respectively.
The next four commands enlarge or shrink a cell. These commands accept numeric arguments (see Arguments) to specify how many columns or rows to enlarge or shrink a particular table.
You can specify text justification for each cell. The justification is remembered independently for each cell and the subsequent editing of cell contents is subject to the specified justification.
The command table-justify requests the user to specify what
to justify: a cell,a column, or a row. If you select cell
justification, this command sets the justification only to the current
cell. Selecting column or row justification set the justification to
all the cells within a column or row respectively. The command then
requests the user to enter which justification to apply: left,
center, right, top, middle, bottom,
or none. The options left, center, and
right specify horizontal justification while the options
top, middle, bottom, and none specify
vertical justification. The vertical justification none
effectively removes vertical justification while horizontal
justification must be one of left, center, or
right. Horizontal justification and vertical justification are
specified independently.
Justification information is stored in the buffer as a part of text
property. Therefore, this information is ephemeral and does not
survive through the loss of the buffer (closing the buffer and
revisiting the buffer erase any previous text properties). To
countermand for this, the command table-recognize and other
recognition commands (see Table Recognition) are equipped with a
convenience feature (turned on by default). During table recognition,
the contents of a cell are examined to determine which justification
was originally applied to the cell and then applies this justification
to the cell. This is a speculative algorithm and is therefore not
perfect, however, the justification is deduced correctly most of the
time. If you desire to disable this feature, customize the variable
table-detect-cell-alignment to set it to nil.
The command table-insert-row inserts a row of cells before
the current row in a table. The current row where point is located is
pushed down after the newly inserted row. A numeric prefix argument
specifies the number of rows to insert. Note that in order to insert
rows after the last row at the bottom of a table, you must
place point below the table, i.e. outside the table, prior to
invoking this command.
The command table-delete-row deletes a row of cells at point.
A numeric prefix argument specifies the number of rows to delete.
The command table-insert-column inserts a column of cells to
the left of the current row in a table. The current column where
point is located at is pushed right of the newly inserted column. To
insert a column to the right side of the right most column, place
point to the right of the rightmost column, which is outside of the
table, prior to invoking this command. A numeric prefix argument
specifies the number of columns to insert.
A command table-delete-column deletes a column of cells at
point. A numeric prefix argument specifies the number of columns to
delete.
The command table-fixed-width-mode toggles fixed width mode
on and off. When the fixed width mode is turned on, editing inside a
cell never changes the cell width; when it is off, the cell width
expands automatically in order to prevent a word from being folded
into multiple lines. By default, the fixed width mode is turned off.
The command table-capture captures plain text in a region and
turns it into a table. Unlike table-recognize (see Table Recognition), the original text does not have a table appearance but
may hold a logical table structure. For example, some elements
separated by known patterns form a two dimensional structure which can
be turned into a table. Look at the numbers below. The numbers are
horizontally separated by a comma and vertically separated by a
newline character.
1, 2, 3, 4
5, 6, 7, 8
, 9, 10
When you invoke M-x table-capture on the above three-line region, the region can be turned into the next table:
+-----+-----+-----+-----+
|1 |2 |3 |4 |
+-----+-----+-----+-----+
|5 |6 |7 |8 |
+-----+-----+-----+-----+
| |9 |10 | |
+-----+-----+-----+-----+
where ‘,’ is used for a column delimiter regexp, a newline is used for a row delimiter regexp, cells are left justified, and minimum cell width is 5.
The command table-release does the opposite of
table-capture. It releases a table by removing the table frame
and cell borders. This leaves the table contents as plain text. One
of the useful applications of table-capture and
table-release is to edit a text in layout. Look at the
following three paragraphs (the latter two are indented with header
lines):
‘table-capture’ is a powerful command however mastering its power
requires some practice. Here is a list of items what it can do.
Parse Cell Items By using column delimiter regular
expression and raw delimiter regular
expression, it parses the specified text
area and extracts cell items from
non-table text and then forms a table out
of them.
Capture Text Area When no delimiters are specified it
creates a single cell table. The text in
the specified region is placed in that
cell.
Applying table-capture to a region containing the above three
paragraphs, with empty strings for column delimiter regexp and row
delimiter regexp, creates a table with a single cell like the
following one.
+-----------------------------------------------------------------+
|‘table-capture’ is a powerful command however mastering its |
|power requires some practice. Here is a list of items what it |
|can do. |
| |
|Parse Cell Items By using column delimiter regular |
| expression and raw delimiter regular |
| expression, it parses the specified text |
| area and extracts cell items from |
| non-table text and then forms a table out |
| of them. |
| |
|Capture Text Area When no delimiters are specified it |
| creates a single cell table. The text in |
| the specified region is placed in that |
| cell. |
+-----------------------------------------------------------------+
By splitting the cell appropriately we now have a table consisting of paragraphs occupying its own cell. Each cell can now be edited independently without affecting the layout of other cells.
+-----------------------------------------------------------------+
|‘table-capture’ is a powerful command however mastering its |
|power requires some practice. Here is a list of items what it |
|can do. |
+---------------------+-------------------------------------------+
|Parse Cell Items |By using column delimiter regular |
| |expression and raw delimiter regular |
| |expression, it parses the specified text |
| |area and extracts cell items from |
| |non-table text and then forms a table out |
| |of them. |
+---------------------+-------------------------------------------+
|Capture Text Area |When no delimiters are specified it |
| |creates a single cell table. The text in |
| |the specified region is placed in that |
| |cell. |
+---------------------+-------------------------------------------+
By applying table-release, which does the opposite process, the
contents become once again plain text. table-release works as
a companion command to table-capture.
The command table-query-dimension analyzes a table structure
and reports information regarding its dimensions. In case of the
above example table, the table-query-dimension command displays
in echo area:
Cell: (21w, 6h), Table: (67w, 16h), Dim: (2c, 3r), Total Cells: 5
This indicates that the current cell is 21 character wide and 6 lines high, the entire table is 67 characters wide and 16 lines high. The table has 2 columns and 3 rows. It has a total of 5 cells, since the first row has a spanned cell.
The command table-insert-sequence inserts a string into each
cell. Each string is a part of a sequence i.e. a series of
increasing integer numbers.
The command table-generate-source generates a table formatted
for a specific markup language. It asks for a language (which must be
one of html, latex, or cals), a destination
buffer where to put the result, and the table caption (a string), and
then inserts the generated table in the proper syntax into the
destination buffer. The default destination buffer is
table.lang, where lang is the language you
specified.
Emacs provides many features to facilitate editing programs. Some of these features can
This chapter describes these features and many more.
Emacs has specialized major modes for various programming languages. See Major Modes. A programming language major mode typically specifies the syntax of expressions, the customary rules for indentation, how to do syntax highlighting for the language, and how to find the beginning of a function definition. It often customizes or provides facilities for compiling and debugging programs as well.
Ideally, Emacs should provide a major mode for each programming
language that you might want to edit; if it doesn't have a mode for
your favorite language, you can contribute one. But often the mode
for one language can serve for other syntactically similar languages.
The major mode for language l is called l-mode,
and you can select it by typing M-x l-mode <RET>.
See Choosing Modes.
The existing programming language major modes include Lisp, Scheme (a variant of Lisp) and the Scheme-based DSSSL expression language, Ada, ASM, AWK, C, C++, Delphi (Object Pascal), Fortran (free format and fixed format), Icon, IDL (CORBA), IDLWAVE, Java, Metafont (TeX's companion for font creation), Modula2, Objective-C, Octave, Pascal, Perl, Pike, PostScript, Prolog, Python, Simula, Tcl, and VHDL. An alternative mode for Perl is called CPerl mode. Modes are available for the scripting languages of the common GNU and Unix shells, VMS DCL, and MS-DOS/MS-Windows ‘BAT’ files. There are also major modes for editing makefiles, DNS master files, and various sorts of configuration files.
In most programming languages, indentation should vary from line to line to illustrate the structure of the program. So the major modes for programming languages arrange for <TAB> to update the indentation of the current line. They also rebind <DEL> to treat a tab as if it were the equivalent number of spaces; this lets you delete one column of indentation without worrying whether the whitespace consists of spaces or tabs. Use C-b C-d to delete a tab character before point, in these modes.
Separate manuals are available for the modes for Ada (see Ada Mode), C/C++/Objective C/Java/Corba IDL/Pike/AWK (see CC Mode) and the IDLWAVE modes (see IDLWAVE).
Turning on a major mode runs a normal hook called the mode
hook, which is the value of a Lisp variable. Each major mode has a
mode hook, and the hook's name is always made from the mode command's
name by adding ‘-hook’. For example, turning on C mode runs the
hook c-mode-hook, while turning on Lisp mode runs the hook
lisp-mode-hook. The purpose of the mode hook is to give you a
place to set up customizations for that major mode. See Hooks.
In Emacs, a major definition at the top level in the buffer, something like a function, is called a defun. The name comes from Lisp, but in Emacs we use it for all languages.
In many programming language modes, Emacs assumes that a defun is any pair of parentheses (or braces, if the language uses braces this way) that starts at the left margin. For example, in C, the body of a function definition is a defun, usually recognized as an open-brace that begins at the left margin12. A variable's initializer can also count as a defun, if the open-brace that begins the initializer is at the left margin.
However, some language modes provide their own code for recognizing defuns in a way that suits the language syntax and conventions better.
Emacs assumes by default that any opening delimiter found at the left margin is the start of a top-level definition, or defun. You can override this default by setting this user option:
If this user option is set to
t(the default), opening parentheses or braces at column zero always start defuns. When it'snil, defuns are found by searching for parens or braces at the outermost level. Some major modes, including C and related modes, setopen-paren-in-column-0-is-defun-startbuffer-locally tonil
In modes where open-paren-in-column-0-is-defun-start is
t, don't put an opening delimiter at the left margin
unless it is a defun start. For instance, never put an
open-parenthesis at the left margin in a Lisp file unless it is the
start of a top-level list.
If you don't follow this convention, not only will you have trouble when you explicitly use the commands for motion by defuns; other features that use them will also give you trouble. This includes the indentation commands (see Program Indent) and Font Lock mode (see Font Lock).
The most likely problem case is when you want an opening delimiter at the start of a line inside a string. To avoid trouble, put an escape character (‘\’, in Emacs Lisp, ‘/’ in some other Lisp dialects) before the opening delimiter. This will not affect the contents of the string, but will prevent that opening delimiter from starting a defun. Here's an example:
(insert "Foo:
\(bar)
")
To help you catch violations of this convention, Font Lock mode highlights confusing opening delimiters (those that ought to be quoted) in bold red.
In the earliest days, the original Emacs found defuns by moving upward a level of parentheses or braces until there were no more levels to go up. This always required scanning all the way back to the beginning of the buffer, even for a small function. To speed up the operation, we changed Emacs to assume that any opening delimiter at the left margin is the start of a defun. This heuristic is nearly always right, and avoids the need to scan back to the beginning of the buffer. However, now that modern computers are so powerful, this scanning is rarely slow enough to annoy, so we've provided a way to disable the heuristic.
These commands move point or set up the region based on top-level major definitions, also called defuns.
beginning-of-defun).
end-of-defun).
mark-defun).
The commands to move to the beginning and end of the current defun
are C-M-a (beginning-of-defun) and C-M-e
(end-of-defun). If you repeat one of these commands, or use a
positive numeric argument, each repetition moves to the next defun in
the direction of motion.
C-M-a with a negative argument −n moves forward n times to the next beginning of a defun. This is not exactly the same place that C-M-e with argument n would move to; the end of this defun is not usually exactly the same place as the beginning of the following defun. (Whitespace, comments, and perhaps declarations can separate them.) Likewise, C-M-e with a negative argument moves back to an end of a defun, which is not quite the same as C-M-a with a positive argument.
To operate on the current defun, use C-M-h (mark-defun)
which puts point at the beginning and mark at the end of the current
defun. This is the easiest way to get ready to kill the defun in
order to move it to a different place in the file. If you use the
command while point is between defuns, it uses the following defun.
Successive uses of C-M-h, or using it in Transient Mark mode
when the mark is active, includes an additional defun in the region
each time.
In C mode, C-M-h runs the function c-mark-function,
which is almost the same as mark-defun; the difference is that
it backs up over the argument declarations, function name and returned
data type so that the entire C function is inside the region. This is
an example of how major modes adjust the standard key bindings so that
they do their standard jobs in a way better fitting a particular
language. Other major modes may replace any or all of these key
bindings for that purpose.
The Imenu facility offers a way to find the major definitions in a file by name. It is also useful in text formatter major modes, where it treats each chapter, section, etc., as a definition. (See Tags, for a more powerful feature that handles multiple files together.)
If you type M-x imenu, it reads the name of a definition using the minibuffer, then moves point to that definition. You can use completion to specify the name; the command always displays the whole list of valid names.
Alternatively, you can bind the command imenu to a mouse
click. Then it displays mouse menus for you to select a definition
name. You can also add the buffer's index to the menu bar by calling
imenu-add-menubar-index. If you want to have this menu bar
item available for all buffers in a certain major mode, you can do
this by adding imenu-add-menubar-index to its mode hook. But
if you have done that, you will have to wait each time you visit a
file in that mode, while Emacs finds all the definitions in that
buffer.
When you change the contents of a buffer, if you add or delete
definitions, you can update the buffer's index based on the
new contents by invoking the ‘*Rescan*’ item in the menu.
Rescanning happens automatically if you set imenu-auto-rescan to
a non-nil value. There is no need to rescan because of small
changes in the text.
You can customize the way the menus are sorted by setting the
variable imenu-sort-function. By default, names are ordered as
they occur in the buffer; if you want alphabetic sorting, use the
symbol imenu--sort-by-name as the value. You can also
define your own comparison function by writing Lisp code.
Imenu provides the information to guide Which Function mode (see Which Function). The Speedbar can also use it (see Speedbar).
Which Function mode is a minor mode that displays the current function name in the mode line, updating it as you move around in a buffer.
To enable (or disable) Which Function mode, use the command M-x
which-function-mode. This command is global; it applies to all
buffers, both existing ones and those yet to be created. However, it
takes effect only in certain major modes, those listed in the value of
which-func-modes. If the value is t, then Which Function
mode applies to all major modes that know how to support it—in other
words, all the major modes that support Imenu.
The best way to keep a program properly indented is to use Emacs to reindent it as you change it. Emacs has commands to indent properly either a single line, a specified number of lines, or all of the lines inside a single parenthetical grouping.
Emacs also provides a Lisp pretty-printer in the library pp.
This program reformats a Lisp object with indentation chosen to look nice.
The basic indentation commands indent a single line according to the usual conventions of the language you are editing.
newline-and-indent).
The basic indentation command is <TAB>, which gives the current line
the correct indentation as determined from the previous lines. The
function that <TAB> runs depends on the major mode; it is
lisp-indent-line
in Lisp mode, c-indent-command in C mode, etc. These functions
understand the syntax and conventions of different languages, but they all do
conceptually the same job: <TAB> in any programming-language major mode
inserts or deletes whitespace at the beginning of the current line,
independent of where point is in the line. If point was inside the
whitespace at the beginning of the line, <TAB> puts it at the end of
that whitespace; otherwise, <TAB> keeps point fixed with respect to
the characters around it.
Use C-q <TAB> to insert a tab character at point.
When entering lines of new code, use C-j
(newline-and-indent), which is equivalent to a <RET>
followed by a <TAB>. C-j at the end of a line creates a
blank line and then gives it the appropriate indentation.
<TAB> indents a line that starts within a parenthetical grouping under the preceding line within the grouping, or the text after the parenthesis. Therefore, if you manually give one of these lines a nonstandard indentation, the lines below will tend to follow it. This behavior is convenient in cases where you have overridden the standard result of <TAB> because you find it unaesthetic for a particular line.
By default, an open-parenthesis, open-brace or other opening
delimiter at the left margin is assumed by Emacs (including the
indentation routines) to be the start of a function. This speeds up
indentation commands. If you will be editing text which contains
opening delimiters in column zero that aren't the beginning of a
functions, even inside strings or comments, you must set
open-paren-in-column-0-is-defun-start. See Left Margin Paren, for more information on this.
Normally, lines are indented with tabs and spaces. If you want Emacs to use spaces only, see Just Spaces.
When you wish to reindent several lines of code which have been altered or moved to a different level in the parenthesis structure, you have several commands available.
indent-pp-sexp).
indent-region).
You can reindent the contents of a single parenthetical grouping by
positioning point before the beginning of it and typing C-M-q
(indent-pp-sexp in Lisp mode, c-indent-exp in C mode; also
bound to other suitable commands in other modes). The indentation of
the line where the grouping starts is not changed; therefore this
changes only the relative indentation within the grouping, not its
overall indentation. To correct that as well, type <TAB> first.
Another way to specify the range to be reindented is with the
region. The command C-M-\ (indent-region) applies
<TAB> to every line whose first character is between point and
mark.
If you like the relative indentation within a grouping, but not the indentation of its first line, you can type C-u <TAB> to reindent the whole grouping as a rigid unit. (This works in Lisp modes and C and related modes.) <TAB> with a numeric argument reindents the current line as usual, then reindents by the same amount all the lines in the parenthetical grouping starting on the current line. It is clever, though, and does not alter lines that start inside strings. Neither does it alter C preprocessor lines when in C mode, but it does reindent any continuation lines that may be attached to them.
You can also perform this operation on the region, using the command
M-x indent-code-rigidly. It rigidly shifts all the lines in the
region sideways, like indent-rigidly does (see Indentation Commands). It doesn't alter the indentation of lines that start
inside a string, unless the region also starts inside that string.
The prefix arg specifies the number of columns to indent.
The indentation pattern for a Lisp expression can depend on the function called by the expression. For each Lisp function, you can choose among several predefined patterns of indentation, or define an arbitrary one with a Lisp program.
The standard pattern of indentation is as follows: the second line of the expression is indented under the first argument, if that is on the same line as the beginning of the expression; otherwise, the second line is indented underneath the function name. Each following line is indented under the previous line whose nesting depth is the same.
If the variable lisp-indent-offset is non-nil, it overrides
the usual indentation pattern for the second line of an expression, so that
such lines are always indented lisp-indent-offset more columns than
the containing list.
Certain functions override the standard pattern. Functions whose
names start with def treat the second lines as the start of
a body, by indenting the second line lisp-body-indent
additional columns beyond the open-parenthesis that starts the
expression.
You can override the standard pattern in various ways for individual
functions, according to the lisp-indent-function property of
the function name. Normally you would use this for macro definitions
and specify it using the declare construct (see Defining Macros).
Here are special features for indentation in C mode and related modes:
C-c C-qc-indent-defun).
C-M-qc-indent-exp). A prefix argument inhibits warning messages
about invalid syntax.
<TAB>c-indent-command).
If c-tab-always-indent is t, this command always reindents
the current line and does nothing else. This is the default.
If that variable is nil, this command reindents the current line
only if point is at the left margin or in the line's indentation;
otherwise, it inserts a tab (or the equivalent number of spaces,
if indent-tabs-mode is nil).
Any other value (not nil or t) means always reindent the
line, and also insert a tab if within a comment or a string.
To reindent the whole current buffer, type C-x h C-M-\. This first selects the whole buffer as the region, then reindents that region.
To reindent the current block, use C-M-u C-M-q. This moves to the front of the block and then reindents it all.
C mode and related modes use a flexible mechanism for customizing indentation. C mode indents a source line in two steps: first it classifies the line syntactically according to its contents and context; second, it determines the indentation offset associated by your selected style with the syntactic construct and adds this onto the indentation of the anchor statement.
c-set-style).
A style is a named collection of customizations that can be
used in C mode and the related modes. Styles, for a complete description. Emacs comes with several
predefined styles, including gnu, k&r, bsd,
stroustrup, linux, python, java,
whitesmith, ellemtel, and awk. Some of these
styles are primarily intended for one language, but any of them can be
used with any of the languages supported by these modes. To find out
what a style looks like, select it and reindent some code, e.g., by
typing <C-M-q> at the start of a function definition.
To choose a style for the current buffer, use the command C-c .. Specify a style name as an argument (case is not significant). This command affects the current buffer only, and it affects only future invocations of the indentation commands; it does not reindent the code already in the buffer. To reindent the whole buffer in the new style, you can type C-x h C-M-\.
You can also set the variable c-default-style to specify the
default style for various major modes. Its value should be either the
style's name (a string) or an alist, in which each element specifies
one major mode and which indentation style to use for it. For
example,
(setq c-default-style
'((java-mode . "java") (awk-mode . "awk") (other . "gnu")))
specifies explicit choices for Java and AWK modes, and the default ‘gnu’ style for the other C-like modes. (These settings are actually the defaults.) This variable takes effect when you select one of the C-like major modes; thus, if you specify a new default style for Java mode, you can make it take effect in an existing Java mode buffer by typing M-x java-mode there.
The gnu style specifies the formatting recommended by the GNU
Project for C; it is the default, so as to encourage use of our
recommended style.
See Indentation Engine Basics, and Customizing Indentation, for more information on customizing indentation for C and related modes, including how to override parts of an existing style and how to define your own styles.
This section describes the commands and features that take advantage of the parenthesis structure in a program, or help you keep it balanced.
When talking about these facilities, the term “parenthesis” also includes braces, brackets, or whatever delimiters are defined to match in pairs. The major mode controls which delimiters are significant, through the syntax table (see Syntax). In Lisp, only parentheses count; in C, these commands apply to braces and brackets too.
You can use M-x check-parens to find any unbalanced parentheses and unbalanced string quotes in the buffer.
These commands deal with balanced expressions, also called sexps13.
forward-sexp).
backward-sexp).
kill-sexp).
transpose-sexps).
mark-sexp).
Each programming language major mode customizes the definition of balanced expressions to suit that language. Balanced expressions typically include symbols, numbers, and string constants, as well as any pair of matching delimiters and their contents. Some languages have obscure forms of expression syntax that nobody has bothered to implement in Emacs.
By convention, the keys for these commands are all Control-Meta characters. They usually act on expressions just as the corresponding Meta characters act on words. For instance, the command C-M-b moves backward over a balanced expression, just as M-b moves back over a word.
To move forward over a balanced expression, use C-M-f
(forward-sexp). If the first significant character after point
is an opening delimiter (‘(’ in Lisp; ‘(’, ‘[’ or
‘{’ in C), C-M-f moves past the matching closing
delimiter. If the character begins a symbol, string, or number,
C-M-f moves over that.
The command C-M-b (backward-sexp) moves backward over a
balanced expression. The detailed rules are like those above for
C-M-f, but with directions reversed. If there are prefix
characters (single-quote, backquote and comma, in Lisp) preceding the
expression, C-M-b moves back over them as well. The balanced
expression commands move across comments as if they were whitespace,
in most modes.
C-M-f or C-M-b with an argument repeats that operation the specified number of times; with a negative argument, it moves in the opposite direction.
Killing a whole balanced expression can be done with C-M-k
(kill-sexp). C-M-k kills the characters that C-M-f
would move over.
A somewhat random-sounding command which is nevertheless handy is
C-M-t (transpose-sexps), which drags the previous
balanced expression across the next one. An argument serves as a
repeat count, moving the previous expression over that many following
ones. A negative argument drags the previous balanced expression
backwards across those before it (thus canceling out the effect of
C-M-t with a positive argument). An argument of zero, rather
than doing nothing, transposes the balanced expressions ending at or
after point and the mark.
To set the region around the next balanced expression in the buffer,
use C-M-@ (mark-sexp), which sets mark at the same place
that C-M-f would move to. C-M-@ takes arguments like
C-M-f. In particular, a negative argument is useful for putting
the mark at the beginning of the previous balanced expression. The
alias C-M-<SPC> is equivalent to C-M-@. When you
repeat this command, or use it in Transient Mark mode when the mark is
active, it extends the region by one sexp each time.
In languages that use infix operators, such as C, it is not possible to recognize all balanced expressions as such because there can be multiple possibilities at a given position. For example, C mode does not treat ‘foo + bar’ as a single expression, even though it is one C expression; instead, it recognizes ‘foo’ as one expression and ‘bar’ as another, with the ‘+’ as punctuation between them. Both ‘foo + bar’ and ‘foo’ are legitimate choices for “the expression following point” when point is at the ‘f’, so the expression commands must perforce choose one or the other to operate on. Note that ‘(foo + bar)’ is recognized as a single expression in C mode, because of the parentheses.
The Emacs commands for handling parenthetical groupings see nothing except parentheses (or whatever characters must balance in the language you are working with), and the escape characters that might be used to quote those. They are mainly intended for editing programs, but can be useful for editing any text that has parentheses. They are sometimes called “list” commands because in Lisp these groupings are lists.
forward-list).
backward-list).
backward-up-list).
down-list).
The “list” commands C-M-n (forward-list) and
C-M-p (backward-list) move over one (or n)
parenthetical groupings, skipping blithely over any amount of text
that doesn't include meaningful parentheses (symbols, strings, etc.).
C-M-n and C-M-p try to stay at the same level in the
parenthesis structure. To move up one (or n) levels, use
C-M-u (backward-up-list). C-M-u moves backward up
past one unmatched opening delimiter. A positive argument serves as a
repeat count; a negative argument reverses the direction of motion, so
that the command moves forward and up one or more levels.
To move down in the parenthesis structure, use C-M-d
(down-list). In Lisp mode, where ‘(’ is the only opening
delimiter, this is nearly the same as searching for a ‘(’. An
argument specifies the number of levels to go down.
The Emacs parenthesis-matching feature is designed to show automatically how parentheses (and other matching delimiters) match in the text. Whenever you type a self-inserting character that is a closing delimiter, the cursor moves momentarily to the location of the matching opening delimiter, provided that is on the screen. If it is not on the screen, Emacs displays some of the text near it in the echo area. Either way, you can tell which grouping you are closing off.
If the opening delimiter and closing delimiter are mismatched—such as in ‘[x)’—a warning message is displayed in the echo area.
Three variables control parenthesis match display:
blink-matching-paren turns the feature on or off: nil
disables it, but the default is t to enable match display.
blink-matching-delay says how many seconds to leave the
cursor on the matching opening delimiter, before bringing it back to
the real location of point; the default is 1, but on some systems it
is useful to specify a fraction of a second.
blink-matching-paren-distance specifies how many characters
back to search to find the matching opening delimiter. If the match
is not found in that distance, scanning stops, and nothing is displayed.
This is to prevent the scan for the matching delimiter from wasting
lots of time when there is no match. The default is 25600.
Show Paren mode provides a more powerful kind of automatic matching. Whenever point is after a closing delimiter, that delimiter and its matching opening delimiter are both highlighted; otherwise, if point is before an opening delimiter, the matching closing delimiter is highlighted. (There is no need to highlight the opening delimiter in that case, because the cursor appears on top of that character.) Use the command M-x show-paren-mode to enable or disable this mode.
By default, show-paren-mode uses colors to highlight the
parentheses. However, if your display doesn't support colors, you can
customize the faces show-paren-match-face and
show-paren-mismatch-face to use other attributes, such as bold or
underline. See Face Customization.
Because comments are such an important part of programming, Emacs provides special commands for editing and inserting comments. It can also do spell checking on comments with Flyspell Prog mode (see Spelling).
The comment commands in this table insert, kill and align comments. They are described in this section and following sections.
comment-dwim).
comment-kill).
comment-set-column).
comment-indent-new-line). See Multi-Line Comments.
The command to create or align a comment is M-;
(comment-dwim). The word “dwim” is an acronym for “Do What
I Mean”; it indicates that this command can be used for many
different jobs relating to comments, depending on the situation where
you use it.
If there is no comment already on the line, M-; inserts a new
comment, aligned at a specific column called the comment column.
The new comment begins with the string Emacs thinks comments should
start with (the value of comment-start; see below). Point is
after that string, so you can insert the text of the comment right
away. If the major mode has specified a string to terminate comments,
M-; inserts that too, to keep the syntax valid.
If the text of the line extends past the comment column, then the comment start string is indented to a suitable boundary (usually, at least one space is inserted).
You can also use M-; to align an existing comment. If a line already contains the comment-start string, M-; reindents it to the conventional alignment and moves point after it. (Exception: comments starting in column 0 are not moved.) Even when an existing comment is properly aligned, M-; is still useful for moving directly to the start of the text inside the comment.
C-u M-; kills any comment on the current line, along with the whitespace before it. To reinsert the comment on another line, move to the end of that line, do C-y, and then do M-; to realign it.
Note that C-u M-; is not a distinct key; it is M-;
(comment-dwim) with a prefix argument. That command is
programmed so that when it receives a prefix argument it calls
comment-kill. However, comment-kill is a valid command
in its own right, and you can bind it directly to a key if you wish.
M-; does two other jobs when used with an active region in
Transient Mark mode (see Transient Mark). Then it either adds or
removes comment delimiters on each line of the region. (If every line
is a comment, it removes comment delimiters from each; otherwise, it
adds comment delimiters to each.) If you are not using Transient Mark
mode, then you should use the commands comment-region and
uncomment-region to do these jobs (see Multi-Line Comments).
A prefix argument used in these circumstances specifies how many
comment delimiters to add or how many to delete.
Some major modes have special rules for indenting certain kinds of comments in certain contexts. For example, in Lisp code, comments which start with two semicolons are indented as if they were lines of code, instead of at the comment column. Comments which start with three semicolons are supposed to start at the left margin. Emacs understands these conventions by indenting a double-semicolon comment using <TAB>, and by not changing the indentation of a triple-semicolon comment at all.
;; This function is just an example
;;; Here either two or three semicolons are appropriate.
(defun foo (x)
;;; And now, the first part of the function:
;; The following line adds one.
(1+ x)) ; This line adds one.
For C-like buffers, you can configure the exact effect of M-;
more flexibly than for most buffers by setting the user options
c-indent-comment-alist and
c-indent-comments-syntactically-p. For example, on a line
ending in a closing brace, M-; puts the comment one space after
the brace rather than at comment-column. For full details see
Comment Commands.
If you are typing a comment and wish to continue it on another line,
you can use the command C-M-j or M-j
(comment-indent-new-line). If comment-multi-line
(see Options for Comments) is non-nil, it moves to a new
line within the comment. Otherwise it closes the comment and starts a
new comment on a new line. When Auto Fill mode is on, going past the
fill column while typing a comment causes the comment to be continued
in just this fashion.
To turn existing lines into comment lines, use the M-x comment-region command (or type C-c C-c in C-like buffers). It adds comment delimiters to the lines that start in the region, thus commenting them out. With a negative argument, it does the opposite—it deletes comment delimiters from the lines in the region.
With a positive argument, comment-region duplicates the last
character of the comment start sequence it adds; the argument specifies
how many copies of the character to insert. Thus, in Lisp mode,
C-u 2 M-x comment-region adds ‘;;’ to each line. Duplicating
the comment delimiter is a way of calling attention to the comment. It
can also affect how the comment is indented. In Lisp, for proper
indentation, you should use an argument of two or three, if between defuns;
if within a defun, it must be three.
You can configure C Mode such that when you type a ‘/’ at the
start of a line in a multi-line block comment, this closes the
comment. Enable the comment-close-slash clean-up for this.
See Clean-ups.
The comment column, the column at which Emacs tries to place
comments, is stored in the variable comment-column. You can
set it to a number explicitly. Alternatively, the command C-x ;
(comment-set-column) sets the comment column to the column
point is at. C-u C-x ; sets the comment column to match the
last comment before point in the buffer, and then does a M-; to
align the current line's comment under the previous one.
The variable comment-column is per-buffer: setting the variable
in the normal fashion affects only the current buffer, but there is a
default value which you can change with setq-default.
See Locals. Many major modes initialize this variable for the
current buffer.
The comment commands recognize comments based on the regular
expression that is the value of the variable comment-start-skip.
Make sure this regexp does not match the null string. It may match more
than the comment starting delimiter in the strictest sense of the word;
for example, in C mode the value of the variable is
"/\\*+ *\\|//+ *", which matches extra stars and spaces
after the ‘/*’ itself, and accepts C++ style comments also.
(Note that ‘\\’ is needed in Lisp syntax to include a ‘\’ in
the string, which is needed to deny the first star its special meaning
in regexp syntax. See Regexp Backslash.)
When a comment command makes a new comment, it inserts the value of
comment-start to begin it. The value of comment-end is
inserted after point, so that it will follow the text that you will
insert into the comment. When comment-end is non-empty, it
should start with a space. For example, in C mode,
comment-start has the value "/* " and
comment-end has the value " */".
The variable comment-padding specifies how many spaces
comment-region should insert on each line between the comment
delimiter and the line's original text. The default is 1, to insert
one space. nil means 0. Alternatively, comment-padding
can hold the actual string to insert.
The variable comment-multi-line controls how C-M-j
(indent-new-comment-line) behaves when used inside a comment.
Specifically, when comment-multi-line is nil, the
command inserts a comment terminator, begins a new line, and finally
inserts a comment starter. Otherwise it does not insert the
terminator and starter, so it effectively continues the current
comment across multiple lines. In languages that allow multi-line
comments, the choice of value for this variable is a matter of taste.
The default for this variable depends on the major mode.
The variable comment-indent-function should contain a function
that will be called to compute the indentation for a newly inserted
comment or for aligning an existing comment. It is set differently by
various major modes. The function is called with no arguments, but with
point at the beginning of the comment, or at the end of a line if a new
comment is to be inserted. It should return the column in which the
comment ought to start. For example, in Lisp mode, the indent hook
function bases its decision on how many semicolons begin an existing
comment, and on the code in the preceding lines.
Emacs provides several features you can use to look up the documentation of functions, variables and commands that you plan to use in your program.
For C, Lisp, and other languages that have documentation in Info,
you can use C-h S (info-lookup-symbol) to view the Info
documentation for a symbol used in the program. You specify the
symbol with the minibuffer; the default is the symbol appearing in the
buffer at point. For example, in C mode this looks for the symbol in
the C Library Manual.
The major mode determines where to look for documentation for the symbol—which Info files to look in, and which indices to search. You can also use M-x info-lookup-file to look for documentation for a file name.
This feature currently supports the modes AWK, Autoconf, Bison, C, Emacs Lisp, LaTeX, M4, Makefile, Octave, Perl, Scheme, and Texinfo, provided you have installed the relevant Info files, which are typically available with the appropriate GNU package.
On Unix, the main form of on-line documentation was the manual page or man page. In the GNU operating system, we hope to replace man pages with better-organized manuals that you can browse with Info (see Misc Help). This process is not finished, so it is still useful to read manual pages.
You can read the man page for an operating system command, library
function, or system call, with the M-x man command. It
runs the man program to format the man page; if the system
permits, it runs man asynchronously, so that you can keep on
editing while the page is being formatted. (On MS-DOS and MS-Windows
3, you cannot edit while Emacs waits for man to finish.) The
result goes in a buffer named ‘*Man topic*’. These buffers
use a special major mode, Man mode, that facilitates scrolling and
jumping to other manual pages. For details, type C-h m while in
a man page buffer.
Each man page belongs to one of ten or more sections, each
named by a digit or by a digit and a letter. Sometimes there are
multiple man pages with the same name in different sections. To read
a man page from a specific section, type
‘topic(section)’ or ‘section topic’
when M-x manual-entry prompts for the topic. For example, to
read the man page for the C library function chmod (as opposed
to a command of the same name), type M-x manual-entry <RET>
chmod(2) <RET> (chmod is a system call, so it is in
section ‘2’).
If you do not specify a section, the results depend on how the
man program works on your system. Some of them display only
the first man page they find. Others display all man pages that have
the specified name, so you can move between them with the M-n
and M-p keys14.
The mode line shows how many manual pages are present in the Man buffer.
By default, Emacs highlights the text in man pages. For a long man
page, highlighting can take substantial time. You can turn off
highlighting of man pages by setting the variable
Man-fontify-manpage-flag to nil.
If you insert the text of a man page into an Emacs buffer in some other fashion, you can use the command M-x Man-fontify-manpage to perform the same conversions that M-x manual-entry does.
An alternative way of reading manual pages is the M-x woman
command15. Unlike M-x man, it does not run any external
programs to format and display the man pages; instead it does the job
in Emacs Lisp, so it works on systems such as MS-Windows, where the
man program (and other programs it uses) are not generally
available.
M-x woman prompts for a name of a manual page, and provides
completion based on the list of manual pages that are installed on
your machine; the list of available manual pages is computed
automatically the first time you invoke woman. The word at
point in the current buffer is used to suggest the default for the
name the manual page.
With a numeric argument, M-x woman recomputes the list of the manual pages used for completion. This is useful if you add or delete manual pages.
If you type a name of a manual page and M-x woman finds that several manual pages by the same name exist in different sections, it pops up a window with possible candidates asking you to choose one of them.
By default, M-x woman looks for manual pages in the
directories specified in the MANPATH environment variable. (If
MANPATH is not set, woman uses a suitable default value,
which can be customized.) More precisely, woman looks for
subdirectories that match the shell wildcard pattern man* in each one
of these directories, and tries to find the manual pages in those
subdirectories. When first invoked, M-x woman converts the
value of MANPATH to a list of directory names and stores that
list in the woman-manpath variable. Changing the value of this
variable is another way to control the list of directories used.
You can also augment the list of directories searched by
woman by setting the value of the woman-path variable.
This variable should hold a list of specific directories which
woman should search, in addition to those in
woman-manpath. Unlike woman-manpath, the directories in
woman-path are searched for the manual pages, not for
man* subdirectories.
Occasionally, you might need to display manual pages that are not in
any of the directories listed by woman-manpath and
woman-path. The M-x woman-find-file command prompts for a
name of a manual page file, with completion, and then formats and
displays that file like M-x woman does.
The first time you invoke M-x woman, it defines the Dired
W key to run the woman-find-file command on the current
line's file. You can disable this by setting the variable
woman-dired-keys to nil. See Dired. In addition,
the Tar-mode w key is define to invoke woman-find-file on
the current line's archive member.
For more information about setting up and using M-x woman, see WoMan.
As you edit Lisp code to be run in Emacs, you can use the commands
C-h f (describe-function) and C-h v
(describe-variable) to view documentation of functions and
variables that you want to use. These commands use the minibuffer to
read the name of a function or variable to document, and display the
documentation in a window. Their default arguments are based on the
code in the neighborhood of point. For C-h f, the default is
the function called in the innermost list containing point. C-h
v uses the symbol name around or adjacent to point as its default.
A more automatic but less powerful method is Eldoc mode. This minor mode constantly displays in the echo area the argument list for the function being called at point. (In other words, it finds the function call that point is contained in, and displays the argument list of that function.) If point is over a documented variable, it shows the first line of the variable's docstring. Eldoc mode applies in Emacs Lisp and Lisp Interaction modes, and perhaps a few others that provide special support for looking up doc strings. Use the command M-x eldoc-mode to enable or disable this feature.
Hideshow minor mode provides selective display of portions of a
program, known as blocks. You can use M-x hs-minor-mode
to enable or disable this mode, or add hs-minor-mode to the
mode hook for certain major modes in order to enable it automatically
for those modes.
Just what constitutes a block depends on the major mode. In C mode or C++ mode, they are delimited by braces, while in Lisp mode and similar modes they are delimited by parentheses. Multi-line comments also count as blocks.
hs-hide-block).
hs-show-block).
hs-toggle-hiding).
hs-mouse-toggle-hiding).
hs-hide-all).
hs-show-all).
hs-hide-level).
These variables exist for customizing Hideshow mode.
hs-hide-comments-when-hiding-allnil says that hs-hide-all should hide comments too.
hs-isearch-opencodecommenttnilhs-special-modes-alistIn Emacs, completion is something you normally do in the minibuffer. But one kind of completion is available in all buffers: completion for symbol names.
The character M-<TAB> runs a command to complete the partial symbol before point against the set of meaningful symbol names. This command inserts at point any additional characters that it can determine from the partial name. (If your window manager defines M-<TAB> to switch windows, you can type <ESC> <TAB> or C-M-i.)
If the partial name in the buffer has multiple possible completions that differ in the very next character, so that it is impossible to complete even one more character, M-<TAB> displays a list of all possible completions in another window.
In most programming language major modes, M-<TAB> runs the
command complete-symbol, which provides two kinds of completion.
Normally it does completion based on a tags table (see Tags); with a
numeric argument (regardless of the value), it does completion based on
the names listed in the Info file indexes for your language. Thus, to
complete the name of a symbol defined in your own program, use
M-<TAB> with no argument; to complete the name of a standard
library function, use C-u M-<TAB>. Of course, Info-based
completion works only if there is an Info file for the standard library
functions of your language, and only if it is installed at your site.
In Emacs-Lisp mode, the name space for completion normally consists of
nontrivial symbols present in Emacs—those that have function
definitions, values or properties. However, if there is an
open-parenthesis immediately before the beginning of the partial symbol,
only symbols with function definitions are considered as completions.
The command which implements this is lisp-complete-symbol.
In Text mode and related modes, M-<TAB> completes words based on the spell-checker's dictionary. See Spelling.
Glasses minor mode makes ‘unreadableIdentifiersLikeThis’
readable by altering the way they display. It knows two different
ways to do this: by displaying underscores between a lower-case letter
and the following capital letter, and by emboldening the capital
letters. It does not alter the buffer text, only the way they
display, so you can use it even on read-only buffers. You can use the
command M-x glasses-mode to enable or disable the mode in the
current buffer; you can also add glasses-mode to the mode hook
of the programming language major modes in which you normally want
to use Glasses mode.
A number of Emacs commands that aren't designed specifically for editing programs are useful for that nonetheless.
The Emacs commands that operate on words, sentences and paragraphs are useful for editing code. Most symbols names contain words (see Words); sentences can be found in strings and comments (see Sentences). Paragraphs in the strict sense can be found in program code (in long comments), but the paragraph commands are useful in other places too, because programming language major modes define paragraphs to begin and end at blank lines (see Paragraphs). Judicious use of blank lines to make the program clearer will also provide useful chunks of text for the paragraph commands to work on. Auto Fill mode, if enabled in a programming language major mode, indents the new lines which it creates.
The selective display feature is useful for looking at the overall structure of a function (see Selective Display). This feature hides the lines that are indented more than a specified amount. Programming modes often support Outline minor mode (see Outline Mode). The Foldout package provides folding-editor features (see Foldout).
The “automatic typing” features may be useful for writing programs. See Autotyping.
This section gives a brief description of the special features available in C, C++, Objective-C, Java, CORBA IDL, Pike and AWK modes. (These are called “C mode and related modes.”) See CC Mode, for a more extensive description of these modes and their special features.
This section describes commands for moving point, in C mode and related modes.
M-x c-beginning-of-defunM-x c-end-of-defunbeginning-of-defun and
end-of-defun search for braces in column zero.) If you are
editing code where the opening brace of a function isn't placed in
column zero, you may wish to bind C-M-a and C-M-e to
these commands. See Moving by Defuns.
C-c C-u‘#elif’ is equivalent to ‘#else’ followed by ‘#if’, so
the function will stop at a ‘#elif’ when going backward, but not
when going forward.
C-c C-pC-c C-nM-ac-beginning-of-statement). If point is already at the beginning
of a statement, move to the beginning of the preceding statement. With
prefix argument n, move back n − 1 statements.
In comments or in strings which span more than one line, this command
moves by sentences instead of statements.
M-ec-end-of-statement).
M-x c-backward-into-nomenclatureIn the GNU project, we recommend using underscores to separate words
within an identifier in C or C++, rather than using case distinctions.
M-x c-forward-into-nomenclatureIn C mode and related modes, certain printing characters are electric—in addition to inserting themselves, they also reindent the current line, and optionally also insert newlines. The “electric” characters are {, }, :, #, ;, ,, <, >, /, *, (, and ).
You might find electric indentation inconvenient if you are editing chaotically indented code. If you are new to CC Mode, you might find it disconcerting. You can toggle electric action with the command C-c C-l; when it is enabled, ‘/l’ appears in the mode line after the mode name:
c-toggle-electric-state). With a
prefix argument, this command enables electric action if the argument
is positive, disables it if it is negative.
Electric characters insert newlines only when, in addition to the electric state, the auto-newline feature is enabled (indicated by ‘/la’ in the mode line after the mode name). You can turn this feature on or off with the command C-c C-a:
c-toggle-auto-newline). With a
prefix argument, this command turns the auto-newline feature on if the
argument is positive, and off if it is negative.
Usually the CC Mode style configures the exact circumstances in which Emacs inserts auto-newlines. You can also configure this directly. See Custom Auto-newlines.
If you want to delete an entire block of whitespace at point, you can use hungry deletion. This deletes all the contiguous whitespace either before point or after point in a single operation. Whitespace here includes tabs and newlines, but not comments or preprocessor commands.
c-hungry-backspace—Delete the entire block of whitespace
preceding point.
c-hungry-delete-forward—Delete the entire block of whitespace
following point.
As an alternative to the above commands, you can enable hungry delete mode. When this feature is enabled (indicated by ‘/h’ in the mode line after the mode name), a single <BS> command deletes all preceding whitespace, not just one space, and a single C-c C-d (but not <delete>) deletes all following whitespace.
c-toggle-hungry-state)16. With a prefix argument,
this command turns the hungry-delete feature on if the argument is
positive, and off if it is negative.
The variable c-hungry-delete-key controls whether the
hungry-delete feature is enabled.
newline-and-indent), in a C preprocessor line it
additionally inserts a ‘\’ at the line break, and within comments
it's like M-j (c-indent-new-comment-line).
c-context-line-break isn't bound to a key by default, but it
needs a binding to be useful. The following code will bind it to
C-j. We use c-initialization-hook here to make sure
the keymap is loaded before we try to change it.
(defun my-bind-clb ()
(define-key c-mode-base-map "\C-j" 'c-context-line-break))
(add-hook 'c-initialization-hook 'my-bind-clb)
c-mark-function).
c-fill-paragraph).
If any part of the current line is a comment or within a comment, this
command fills the comment or the paragraph of it that point is in,
preserving the comment indentation and comment delimiters.
c-macro-expand). The buffer text before the region is also
included in preprocessing, for the sake of macros defined there, but the
output from this part isn't shown.
When you are debugging C code that uses macros, sometimes it is hard to
figure out precisely how the macros expand. With this command, you
don't have to figure it out; you can see the expansions.
c-backslash-region). This is useful after writing or
editing a C macro definition.
If a line already ends in ‘\’, this command adjusts the amount of
whitespace before it. Otherwise, it inserts a new ‘\’. However,
the last line in the region is treated specially; no ‘\’ is
inserted on that line, and any ‘\’ there is deleted.
c-show-syntactic-information). This information directs how
the line is indented.
You can enable the mode for one buffer with the command M-x
cwarn-mode, or for all suitable buffers with the command M-x
global-cwarn-mode or by customizing the variable
global-cwarn-mode. You must also enable Font Lock mode to make
it work.
hide-ifdef-mode for more information.
ff-related-file-alist specifies how to compute related file
names.
Fortran mode provides special motion commands for Fortran statements and subprograms, and indentation commands that understand Fortran conventions of nesting, line numbers and continuation statements. Fortran mode has support for Auto Fill mode that breaks long lines into proper Fortran continuation lines.
Special commands for comments are provided because Fortran comments are unlike those of other languages. Built-in abbrevs optionally save typing when you insert Fortran keywords.
Use M-x fortran-mode to switch to this major mode. This command
runs the hook fortran-mode-hook (see Hooks).
Fortran mode is meant for editing Fortran77 “fixed format” (and also
“tab format”) source code. For editing the modern Fortran90 or
Fortran95 “free format” source code, use F90 mode (f90-mode).
Emacs normally uses Fortran mode for files with extension ‘.f’,
‘.F’ or ‘.for’, and F90 mode for the extension ‘.f90’ and
‘.f95’. GNU Fortran supports both kinds of format.
In addition to the normal commands for moving by and operating on “defuns” (Fortran subprograms—functions and subroutines, as well as modules for F90 mode), Fortran mode provides special commands to move by statements and other program units.
fortran-next-statement/f90-next-statement).
fortran-previous-statement/f90-previous-statement).
If there is no previous statement (i.e. if called from the first
statement in the buffer), move to the start of the buffer.
f90-next-block). A code block is a subroutine,
if–endif statement, and so forth. This command exists
for F90 mode only, not Fortran mode. With a numeric argument, this
moves forward that many blocks.
f90-previous-block). This is like f90-next-block, but
moves backwards.
fortran-end-of-block/f90-end-of-block). With a numeric
agument, move forward that number of blocks. The mark is set before
moving point. The F90 mode version of this command checks for
consistency of block types and labels (if present), but it does not
check the outermost block since that may be incomplete.
fortran-beginning-of-block/f90-beginning-of-block). This
is like fortran-end-of-block, but moves backwards.
Special commands and features are needed for indenting Fortran code in order to make sure various syntactic entities (line numbers, comment line indicators and continuation line flags) appear in the columns that are required for standard, fixed (or tab) format Fortran.
fortran-split-line).
fortran-join-line).
fortran-indent-subprogram).
The key C-M-q runs fortran-indent-subprogram, a command
to reindent all the lines of the Fortran subprogram (function or
subroutine) containing point.
The key C-M-j runs fortran-split-line, which splits
a line in the appropriate fashion for Fortran. In a non-comment line,
the second half becomes a continuation line and is indented
accordingly. In a comment line, both halves become separate comment
lines.
M-^ or C-c C-d runs the command fortran-join-line,
which joins a continuation line back to the previous line, roughly as
the inverse of fortran-split-line. The point must be on a
continuation line when this command is invoked.
M-q in Fortran mode fills the comment block or statement that point is in. This removes any excess statement continuations.
Most Fortran77 compilers allow two ways of writing continuation lines.
If the first non-space character on a line is in column 5, then that
line is a continuation of the previous line. We call this fixed
format. (In GNU Emacs we always count columns from 0; but note that
the Fortran standard counts from 1.) The variable
fortran-continuation-string specifies what character to put in
column 5. A line that starts with a tab character followed by any digit
except ‘0’ is also a continuation line. We call this style of
continuation tab format. (Fortran90 introduced “free format”,
with another style of continuation lines).
Fortran mode can use either style of continuation line. When you
enter Fortran mode, it tries to deduce the proper continuation style
automatically from the buffer contents. It does this by scanning up to
fortran-analyze-depth (default 100) lines from the start of the
buffer. The first line that begins with either a tab character or six
spaces determines the choice. If the scan fails (for example, if the
buffer is new and therefore empty), the value of
fortran-tab-mode-default (nil for fixed format, and
non-nil for tab format) is used. ‘/t’ in the mode line
indicates tab format is selected. Fortran mode sets the value of
indent-tabs-mode accordingly (see Just Spaces).
If the text on a line starts with the Fortran continuation marker ‘$’, or if it begins with any non-whitespace character in column 5, Fortran mode treats it as a continuation line. When you indent a continuation line with <TAB>, it converts the line to the current continuation style. When you split a Fortran statement with C-M-j, the continuation marker on the newline is created according to the continuation style.
The setting of continuation style affects several other aspects of editing in Fortran mode. In fixed format mode, the minimum column number for the body of a statement is 6. Lines inside of Fortran blocks that are indented to larger column numbers always use only the space character for whitespace. In tab format mode, the minimum column number for the statement body is 8, and the whitespace before column 8 must always consist of one tab character.
If a number is the first non-whitespace in the line, Fortran indentation assumes it is a line number and moves it to columns 0 through 4. (Columns always count from 0 in GNU Emacs.)
Line numbers of four digits or less are normally indented one space.
The variable fortran-line-number-indent controls this; it
specifies the maximum indentation a line number can have. The default
value of the variable is 1. Fortran mode tries to prevent line number
digits passing column 4, reducing the indentation below the specified
maximum if necessary. If fortran-line-number-indent has the
value 5, line numbers are right-justified to end in column 4.
Simply inserting a line number is enough to indent it according to
these rules. As each digit is inserted, the indentation is recomputed.
To turn off this feature, set the variable
fortran-electric-line-number to nil.
Fortran mode assumes that you follow certain conventions that simplify the task of understanding a Fortran program well enough to indent it properly:
Fortran compilers generally ignore whitespace outside of string constants, but Fortran mode does not recognize these keywords if they are not contiguous. Constructs such as ‘else if’ or ‘end do’ are acceptable, but the second word should be on the same line as the first and not on a continuation line.
If you fail to follow these conventions, the indentation commands may indent some lines unaesthetically. However, a correct Fortran program retains its meaning when reindented even if the conventions are not followed.
Several additional variables control how Fortran indentation works:
fortran-do-indentfortran-if-indentfortran-structure-indentfortran-continuation-indentfortran-check-all-num-for-matching-donil value, indenting any numbered statement must check for a
‘do’ that ends there. If you always end ‘do’ statements with
a ‘continue’ line (or if you use the more modern ‘enddo’),
then you can speed up indentation by setting this variable to
nil. The default is nil.
fortran-blink-matching-ift, indenting an ‘endif’ (or ‘enddo’
statement moves the cursor momentarily to the matching ‘if’ (or
‘do’) statement to show where it is. The default is nil.
fortran-minimum-statement-indent-fixedfortran-minimum-statement-indent-tabThe variables controlling the indentation of comments are described in the following section.
The usual Emacs comment commands assume that a comment can follow a line of code. In Fortran77, the standard comment syntax requires an entire line to be just a comment. Therefore, Fortran mode replaces the standard Emacs comment commands and defines some new variables.
Fortran mode can also handle the Fortran90 comment syntax where comments
start with ‘!’ and can follow other text. Because only some Fortran77
compilers accept this syntax, Fortran mode will not insert such comments
unless you have said in advance to do so. To do this, set the variable
fortran-comment-line-start to ‘"!"’.
fortran-indent-comment).
fortran-comment-region).
M-; in Fortran mode is redefined as the command
fortran-indent-comment. Like the usual M-; command, this
recognizes any kind of existing comment and aligns its text appropriately;
if there is no existing comment, a comment is inserted and aligned. But
inserting and aligning comments are not the same in Fortran mode as in
other modes.
When a new comment must be inserted, if the current line is blank, a full-line comment is inserted. On a non-blank line, a nonstandard ‘!’ comment is inserted if you have said you want to use them. Otherwise a full-line comment is inserted on a new line before the current line.
Nonstandard ‘!’ comments are aligned like comments in other
languages, but full-line comments are different. In a standard full-line
comment, the comment delimiter itself must always appear in column zero.
What can be aligned is the text within the comment. You can choose from
three styles of alignment by setting the variable
fortran-comment-indent-style to one of these values:
fixedfortran-comment-line-extra-indent and the minimum statement
indentation. This is the default.
The minimum statement indentation is
fortran-minimum-statement-indent-fixed for fixed format
continuation line style and fortran-minimum-statement-indent-tab
for tab format style.
relativefortran-comment-line-extra-indent columns of indentation.
nil In addition, you can specify the character to be used to indent within
full-line comments by setting the variable
fortran-comment-indent-char to the single-character string you want
to use.
Compiler directive lines, or preprocessor lines, have much the same
appearance as comment lines. It is important, though, that such lines
never be indented at all, no matter what the value of
fortran-comment-indent-style. The variable
fortran-directive-re is a regular expression that specifies which
lines are directives. Matching lines are never indented, and receive
distinctive font-locking.
The normal Emacs comment command C-x ; has not been redefined. If you use ‘!’ comments, this command can be used with them. Otherwise it is useless in Fortran mode.
The command C-c ; (fortran-comment-region) turns all the
lines of the region into comments by inserting the string ‘C$$$’ at
the front of each one. With a numeric argument, it turns the region
back into live code by deleting ‘C$$$’ from the front of each line
in it. The string used for these comments can be controlled by setting
the variable fortran-comment-region. Note that here we have an
example of a command and a variable with the same name; these two uses
of the name never conflict because in Lisp and in Emacs it is always
clear from the context which one is meant.
Fortran mode has specialized support for Auto Fill mode, which is a
minor mode that automatically splits statements as you insert them when
they become too wide. Splitting a statement involves making
continuation lines using fortran-continuation-string
(see ForIndent Cont). This splitting happens when you type
<SPC>, <RET>, or <TAB>, and also in the Fortran indentation
commands. You activate Auto Fill in Fortran mode in the normal way
(see Auto Fill).
Auto Fill breaks lines at spaces or delimiters when the lines get
longer than the desired width (the value of fill-column). The
delimiters (besides whitespace) that Auto Fill can break at are
‘+’, ‘-’, ‘/’, ‘*’, ‘=’, ‘<’, ‘>’,
and ‘,’. The line break comes after the delimiter if the
variable fortran-break-before-delimiters is nil.
Otherwise (and by default), the break comes before the delimiter.
To enable Auto Fill in all Fortran buffers, add
turn-on-auto-fill to fortran-mode-hook. See Hooks.
fortran-column-ruler).
fortran-window-create-momentarily). This may
help you avoid making lines longer than the 72-character limit that
some Fortran compilers impose.
fortran-window-create). You can then continue editing.
The command C-c C-r (fortran-column-ruler) shows a column
ruler momentarily above the current line. The comment ruler is two lines
of text that show you the locations of columns with special significance in
Fortran programs. Square brackets show the limits of the columns for line
numbers, and curly brackets show the limits of the columns for the
statement body. Column numbers appear above them.
Note that the column numbers count from zero, as always in GNU Emacs. As a result, the numbers may be one less than those you are familiar with; but the positions they indicate in the line are standard for Fortran.
The text used to display the column ruler depends on the value of the
variable indent-tabs-mode. If indent-tabs-mode is
nil, then the value of the variable
fortran-column-ruler-fixed is used as the column ruler.
Otherwise, the value of the variable fortran-column-ruler-tab is
displayed. By changing these variables, you can change the column ruler
display.
C-c C-w (fortran-window-create-momentarily) temporarily
splits the current window horizontally, making a window 72 columns
wide, so you can see any lines that are too long. Type a space to
restore the normal width.
You can also split the window horizontally and continue editing with
the split in place. To do this, use C-u C-c C-w (M-x
fortran-window-create). By editing in this window you can
immediately see when you make a line too wide to be correct Fortran.
The command M-x fortran-strip-sequence-nos deletes all text in column 72 and beyond, on all lines in the current buffer. This is the easiest way to get rid of old sequence numbers.
Fortran mode provides many built-in abbrevs for common keywords and declarations. These are the same sort of abbrev that you can define yourself. To use them, you must turn on Abbrev mode. See Abbrevs.
The built-in abbrevs are unusual in one way: they all start with a semicolon. You cannot normally use semicolon in an abbrev, but Fortran mode makes this possible by changing the syntax of semicolon to “word constituent.”
For example, one built-in Fortran abbrev is ‘;c’ for ‘continue’. If you insert ‘;c’ and then insert a punctuation character such as a space or a newline, the ‘;c’ expands automatically to ‘continue’, provided Abbrev mode is enabled.
Type ‘;?’ or ‘;C-h’ to display a list of all the built-in Fortran abbrevs and what they stand for.
Asm mode is a major mode for editing files of assembler code. It defines these commands:
tab-to-tab-stop.
tab-to-tab-stop.
tab-to-tab-stop.
The variable asm-comment-char specifies which character
starts comments in assembler syntax.
The previous chapter discusses the Emacs commands that are useful for making changes in programs. This chapter deals with commands that assist in the larger process of developing and maintaining programs.
Emacs can run compilers for noninteractive languages such as C and Fortran as inferior processes, feeding the error log into an Emacs buffer. It can also parse the error messages and show you the source lines where compilation errors occurred.
To run make or another compilation command, do M-x
compile. This command reads a shell command line using the minibuffer,
and then executes the command in an inferior shell, putting output in
the buffer named ‘*compilation*’. The current buffer's default
directory is used as the working directory for the execution of the
command; normally, therefore, the compilation happens in this
directory.
The default for the compilation command is normally ‘make -k’,
which is correct most of the time for nontrivial programs.
(See Make.) If you have done M-x
compile before, the default each time is the command you used the
previous time. compile stores this command in the variable
compile-command, so setting that variable specifies the default
for the next use of M-x compile. If a file specifies a file
local value for compile-command, that provides the default when
you type M-x compile in that file's buffer. See File Variables.
Starting a compilation displays the buffer ‘*compilation*’ in another window but does not select it. The buffer's mode line tells you whether compilation is finished, with the word ‘run’, ‘signal’ or ‘exit’ inside the parentheses. You do not have to keep this buffer visible; compilation continues in any case. While a compilation is going on, the string ‘Compiling’ appears in the mode lines of all windows. When this string disappears, the compilation is finished.
If you want to watch the compilation transcript as it appears, switch to the ‘*compilation*’ buffer and move point to the end of the buffer. When point is at the end, new compilation output is inserted above point, which remains at the end. If point is not at the end of the buffer, it remains fixed while more compilation output is added at the end of the buffer.
If you set the variable compilation-scroll-output to a
non-nil value, then the compilation buffer always scrolls to
follow output as it comes in.
When the compiler process terminates, for whatever reason, the mode line of the ‘*compilation*’ buffer changes to say ‘exit’ (followed by the exit code, ‘[0]’ for a normal exit), or ‘signal’ (if a signal terminated the process), instead of ‘run’. Starting a new compilation also kills any running compilation, as only one can exist at any time. However, M-x compile asks for confirmation before actually killing a compilation that is running. You can also kill the compilation process with M-x kill-compilation.
To rerun the last compilation with the same command, type M-x recompile. This automatically reuses the compilation command from the last invocation of M-x compile. It also reuses the ‘*compilation*’ buffer and starts the compilation in its default directory, which is the directory in which the previous compilation was started.
Emacs does not expect a compiler process to launch asynchronous subprocesses; if it does, and they keep running after the main compiler process has terminated, Emacs may kill them or their output may not arrive in Emacs. To avoid this problem, make the main process wait for its subprocesses to finish. In a shell script, you can do this using ‘$!’ and ‘wait’, like this:
(sleep 10; echo 2nd)& pid=$! # Record pid of subprocess echo first message wait $pid # Wait for subprocess
If the background process does not output to the compilation buffer, so you only need to prevent it from being killed when the main compilation process terminates, this is sufficient:
nohup command; sleep 1
You can control the environment passed to the compilation command
with the variable compilation-environment. Its value is a list
of environment variable settings; each element should be a string of
the form "envvarname=value". These environment
variable settings override the usual ones.
The ‘*compilation*’ buffer uses a special major mode, Compilation mode, whose main feature is to provide a convenient way to look at the source line where the error happened.
grep match.
grep match.
You can visit the source for any particular error message by moving
point in the ‘*compilation*’ buffer to that error message and
typing <RET> (compile-goto-error). Alternatively, you can
click Mouse-2 on the error message; you need not switch to the
‘*compilation*’ buffer first.
To parse the compiler error messages sequentially, type C-x `
(next-error). The character following the C-x is the
backquote or “grave accent,” not the single-quote. This command is
available in all buffers, not just in ‘*compilation*’; it
displays the next error message at the top of one window and source
location of the error in another window. It also momentarily
highlights the relevant source line. You can change the behavior of
this highlighting with the variable next-error-highlight.
The first time C-x ` is used after the start of a compilation, it moves to the first error's location. Subsequent uses of C-x ` advance down to subsequent errors. If you visit a specific error message with <RET> or Mouse-2, subsequent C-x ` commands advance from there. When C-x ` gets to the end of the buffer and finds no more error messages to visit, it fails and signals an Emacs error.
By default, C-x ` skips less important messages. The variable
compilation-skip-threshold controls this. If its value is 2,
C-x ` skips anything less than error, 1 skips anything less
than warning, and 0 doesn't skip any messages.
When the left fringe is displayed, an arrow points to the
current message in the compilation buffer. The variable
compilation-context-lines controls the number of lines of
leading context in the window before the current message. If it is
nil and the left fringe is displayed, the window doesn't
scroll. If there is no left fringe, no arrow is displayed and a value
of nil means display the message at the top of the window.
If you're not in the compilation buffer when you run
next-error, Emacs will look for a buffer that contains error
messages. First, it looks for one displayed in the selected frame,
then for one that previously had next-error called on it, and
then at the current buffer. Finally, Emacs looks at all the remaining
buffers. next-error signals an error if it can't find any such
buffer.
C-u C-x ` starts scanning from the beginning of the compilation buffer. This is one way to process the same set of errors again.
To parse messages from the compiler, Compilation mode uses the
variable compilation-error-regexp-alist which lists various
formats of error messages and tells Emacs how to extract the source file
and the line number from the text of a message. If your compiler isn't
supported, you can tailor Compilation mode to it by adding elements to
that list. A similar variable grep-regexp-alist tells Emacs how
to parse output of a grep command.
Compilation mode also redefines the keys <SPC> and <DEL> to
scroll by screenfuls, and M-n (compilation-next-error)
and M-p (compilation-previous-error) to move to the next
or previous error message. You can also use M-{
(compilation-next-file and M-}
(compilation-previous-file) to move up or down to an error
message for a different source file.
You can type C-c C-f to toggle Next Error Follow mode. In this minor mode, ordinary cursor motion in the compilation buffer automatically updates the source buffer. For instance, moving the cursor to the next error message causes the location of that error to be displayed immediately.
The features of Compilation mode are also available in a minor mode called Compilation Minor mode. This lets you parse error messages in any buffer, not just a normal compilation output buffer. Type M-x compilation-minor-mode to enable the minor mode. This defines the keys <RET> and Mouse-2, as in the Compilation major mode.
Compilation minor mode works in any buffer, as long as the contents are in a format that it understands. In an Rlogin buffer (see Remote Host), Compilation minor mode automatically accesses remote source files by FTP (see File Names).
Emacs uses a shell to run the compilation command, but specifies the option for a noninteractive shell. This means, in particular, that the shell should start with no prompt. If you find your usual shell prompt making an unsightly appearance in the ‘*compilation*’ buffer, it means you have made a mistake in your shell's init file by setting the prompt unconditionally. (This init file's name may be .bashrc, .profile, .cshrc, .shrc, or various other things, depending on the shell you use.) The shell init file should set the prompt only if there already is a prompt. In csh, here is how to do it:
if ($?prompt) set prompt = ...
And here's how to do it in bash:
if [ "${PS1+set}" = set ]
then PS1=...
fi
There may well be other things that your shell's init file ought to do only for an interactive shell. You can use the same method to conditionalize them.
The MS-DOS “operating system” does not support asynchronous subprocesses; to work around this lack, M-x compile runs the compilation command synchronously on MS-DOS. As a consequence, you must wait until the command finishes before you can do anything else in Emacs. See MS-DOS.
Just as you can run a compiler from Emacs and then visit the lines
with compilation errors, you can also run grep and
then visit the lines on which matches were found. This works by
treating the matches reported by grep as if they were “errors.”
grep asynchronously under Emacs, with matching lines
listed in the buffer named ‘*grep*’.
grep via find, with user-specified arguments, and
collect output in the buffer named ‘*grep*’.
grep subprocess.
To run grep, type M-x grep, then enter a command line that
specifies how to run grep. Use the same arguments you would give
grep when running it normally: a grep-style regexp
(usually in single-quotes to quote the shell's special characters)
followed by file names, which may use wildcards. If you specify a
prefix argument for M-x grep, it figures out the tag
(see Tags) around point, and puts that into the default
grep command.
The output from grep goes in the ‘*grep*’ buffer. You
can find the corresponding lines in the original files using C-x
`, <RET>, and so forth, just like compilation errors.
Some grep programs accept a ‘--color’ option to output special
markers around matches for the purpose of highlighting. You can make
use of this feature by setting grep-highlight-matches to
t. When displaying a match in the source buffer, the exact
match will be highlighted, instead of the entire source line.
The command M-x grep-find (also available as M-x
find-grep) is similar to M-x grep, but it supplies a different
initial default for the command—one that runs both find and
grep, so as to search every file in a directory tree. See also
the find-grep-dired command, in Dired and Find.
Flymake mode is a minor mode that performs on-the-fly syntax
checking for many programming and markup languages, including C, C++,
Perl, HTML, and TeX/LaTeX. It is somewhat analogous to Flyspell
mode, which performs spell checking for ordinary human languages in a
similar fashion (see Spelling). As you edit a file, Flymake mode
runs an appropriate syntax checking tool in the background, using a
temporary copy of the buffer. It then parses the error and warning
messages, and highlights the erroneous lines in the buffer. The
syntax checking tool used depends on the language; for example, for
C/C++ files this is usually the C compiler. Flymake can also use
build tools such as make for checking complicated projects.
To activate Flymake mode, type M-x flymake-mode. You can move to the errors spotted by Flymake mode with M-x flymake-goto-next-error and M-x flymake-goto-prev-error. To display any error messages associated with the current line, use M-x flymake-display-err-menu-for-current-line.
For more details about using Flymake, see Flymake.
The GUD (Grand Unified Debugger) library provides an interface to various symbolic debuggers from within Emacs. We recommend the debugger GDB, which is free software, but you can also run DBX, SDB or XDB if you have them. GUD can also serve as an interface to Perl's debugging mode, the Python debugger PDB, the bash debugger, and to JDB, the Java Debugger. See The Lisp Debugger, for information on debugging Emacs Lisp programs.
There are several commands for starting a debugger, each corresponding to a particular debugger program.
gud-xdb-directories to specify directories to search for source
files.
Some versions of SDB do not mention source file names in their
messages. When you use them, you need to have a valid tags table
(see Tags) in order for GUD to find functions in the source code.
If you have not visited a tags table or the tags table doesn't list one
of the functions, you get a message saying ‘The sdb support
requires a valid tags table to work’. If this happens, generate a valid
tags table in the working directory and try again.
Each of these commands takes one argument: a command line to invoke the debugger. In the simplest case, specify just the name of the executable file you want to debug. You may also use options that the debugger supports. However, shell wildcards and variables are not allowed. GUD assumes that the first argument not starting with a ‘-’ is the executable file name.
When you run a debugger with GUD, the debugger uses an Emacs buffer for its ordinary input and output. This is called the GUD buffer. The debugger displays the source files of the program by visiting them in Emacs buffers. An arrow (‘=>’) in one of these buffers indicates the current execution line.17 Moving point in this buffer does not move the arrow.
You can start editing these source files at any time in the buffers that display them. The arrow is not part of the file's text; it appears only on the screen. If you do modify a source file, keep in mind that inserting or deleting lines will throw off the arrow's positioning; GUD has no way of figuring out which line corresponded before your changes to the line number in a debugger message. Also, you'll typically have to recompile and restart the program for your changes to be reflected in the debugger's tables.
If you wish, you can control your debugger process entirely through the debugger buffer, which uses a variant of Shell mode. All the usual commands for your debugger are available, and you can use the Shell mode history commands to repeat them. See Shell Mode.
The Tooltip facility (see Tooltips) provides support for GUD.
You activate this feature by turning on the minor mode
gud-tooltip-mode. Then you can display a variable's value in a
tooltip simply by pointing at it with the mouse. In graphical mode,
with a C program, you can also display the #define directive
associated with an identifier when the program is not executing. This
operates in the GUD buffer and in source buffers with major modes in
the list gud-tooltip-modes. If the variable
gud-tooltip-echo-area is non-nil then the variable's
value is displayed in the echo area.
With GDB in text command mode (see GDB Graphical Interface), it is possible that use of GUD tooltips can cause a function to be called with harmful side-effects. In this case, Emacs disables them.
The GUD interaction buffer uses a variant of Shell mode, so the commands of Shell mode are available (see Shell Mode). GUD mode also provides commands for setting and clearing breakpoints, for selecting stack frames, and for stepping through the program. These commands are available both in the GUD buffer and globally, but with different key bindings. It also has its own tool bar from which you can invoke the more common commands by clicking on the appropriate icon. This is particularly useful for repetitive commands like gud-next and gud-step and allows the user to hide the GUD buffer.
The breakpoint commands are normally used in source file buffers, because that is the easiest way to specify where to set or clear the breakpoint. Here's the global command to set a breakpoint:
Here are the other special commands provided by GUD. The keys starting with C-c are available only in the GUD interaction buffer. The key bindings that start with C-x C-a are available in the GUD interaction buffer and also in source files.
gud-refresh.
gud-step). If the line contains
a function call, execution stops after entering the called function.
gud-next).
gud-stepi).
gud-cont).
gud-remove). If you use this command in the GUD interaction
buffer, it applies to the line where the program last stopped.
The above commands are common to all supported debuggers. If you are using GDB or (some versions of) DBX, these additional commands are available:
gud-up). This is
equivalent to the ‘up’ command.
gud-down). This is
equivalent to the ‘down’ command.
If you are using GDB, these additional key bindings are available:
gud-run).
gud-until).
gud-gdb-complete-command).
This key is available only in the GUD interaction buffer, and requires
GDB versions 4.13 and later.
gud-jump) transfers the
program's execution point to the current line. In other words, the
next line that the program executes will be the one where you gave the
command. If the new execution line is in a different function from
the previously one, GDB prompts for confirmation since the results may
be bizarre. See the GDB manual entry regarding jump for
details.
These commands interpret a numeric argument as a repeat count, when that makes sense.
Because <TAB> serves as a completion command, you can't use it to enter a tab as input to the program you are debugging with GDB. Instead, type C-q <TAB> to enter a tab.
On startup, GUD runs one of the following hooks: gdb-mode-hook,
if you are using GDB; dbx-mode-hook, if you are using DBX;
sdb-mode-hook, if you are using SDB; xdb-mode-hook, if you
are using XDB; perldb-mode-hook, for Perl debugging mode;
pdb-mode-hook, for PDB; jdb-mode-hook, for JDB. You can
use these hooks to define custom key bindings for the debugger
interaction buffer. See Hooks.
Here is a convenient way to define a command that sends a particular command string to the debugger, and set up a key binding for it in the debugger interaction buffer:
(gud-def function cmdstring binding docstring)
This defines a command named function which sends
cmdstring to the debugger process, and gives it the documentation
string docstring. You can then use the command function in any
buffer. If binding is non-nil, gud-def also binds
the command to C-c binding in the GUD buffer's mode and to
C-x C-a binding generally.
The command string cmdstring may contain certain ‘%’-sequences that stand for data to be filled in at the time function is called:
If you don't use ‘%p’ in the command string, the command you define ignores any numeric argument.
By default, the command gdb starts GDB using a graphical
interface where you view and control the program's data using Emacs
windows. You can still interact with GDB through the GUD buffer, but
the point of this mode is that you can do it through menus and clicks,
without needing to know GDB commands. For example, you can click
Mouse-1 in the fringe or display margin of a source buffer to
set a breakpoint there and, on a graphical display, a red bullet will
appear. If a breakpoint already exists on that line, this action will
remove it. You can also enable or disable a breakpoint by clicking
Mouse-3 on the bullet. If you drag the debugger arrow in the
fringe with Mouse-1, execution will continue to the line where
you release the button, provided it is still in the same frame
(gdb-mouse-until). Alternatively, you can click Mouse-2
at some point in the fringe of this buffer and execution will advance
to there.
This mode requires that GDB think that the screen size is unlimited, and sets the height and width accordingly. For correct operation it is important that you don't change these values during the session.
You can also run GDB in text command mode, which creates a buffer
for input and output to GDB. To do this, set
gud-gdb-command-name to "gdb --fullname" or edit the
startup command in the minibuffer to say that. You need to do use
text command mode to run multiple debugging sessions within one Emacs
session. If you have customized gud-gdb-command-name in that
way, then you can use M-x gdba to invoke GDB in graphical mode.
If the variable gdb-many-windows is nil (the default
value) then gdb just pops up the GUD buffer unless the variable
gdb-show-main is non-nil. In this case it starts with
two windows: one displaying the GUD buffer and the other with the
source file with the main routine of the inferior.
If gdb-many-windows is non-nil, regardless of the value of
gdb-show-main, the layout below will appear unless
gdb-use-inferior-io-buffer is nil. In this case the
source buffer occupies the full width of the frame.
+--------------------------------+--------------------------------+
| | |
| GUD buffer (I/O of GDB) | Locals buffer |
| | |
|--------------------------------+--------------------------------+
| | |
| Source buffer | I/O buffer (of inferior) |
| | |
|--------------------------------+--------------------------------+
| | |
| Stack buffer | Breakpoints buffer |
| | |
+--------------------------------+--------------------------------+
To toggle this layout, do M-x gdb-many-windows.
If you change the window layout, for example, while editing and
re-compiling your program, then you can restore it with the command
gdb-restore-windows.
You may also choose which additional buffers you want to display,
either in the same frame or a different one. Select them from
‘GUD->GDB-windows’ or ‘GUD->GDB-Frames’ sub-menu
respectively. If the menu-bar is unavailable, type M-x
gdb-display-buffertype-buffer or M-x
gdb-frame-buffertype-buffer respectively, where
buffertype is the relevant buffer type e.g breakpoints.
Most of these buffers are read-only and be killed by simply
pressing q in them.
When you finish debugging then kill the GUD buffer with C-x k, which will also kill all the buffers associated with the session. However you need not do this if, after editing and re-compiling your source code within Emacs, you wish continue debugging. When you restart execution, GDB will automatically find your new executable. Keeping the GUD buffer has the advantage of keeping the shell history as well as GDB's breakpoints. You need to check, however, that the breakpoints in the recently edited code are still where you want them.
The breakpoints buffer shows the existing breakpoints and watchpoints (see Breakpoints). It has three special commands:
gdb-toggle-breakpoint). On a graphical display, this changes
the color of a bullet in the margin of the source buffer at the
relevant line. This is red when the breakpoint is enabled and grey
when it is disabled. Text-only terminals correspondingly display
a ‘B’ or ‘b’.
gdb-delete-breakpoint).
gdb-goto-breakpoint). Alternatively, click
Mouse-2 on the breakpoint that you wish to visit.
The stack buffer displays a call stack, with one line for each of the nested subroutine calls (stack frames) now active in the program. See Backtraces.
The selected frame number is displayed in reverse contrast. Move
point to any frame in the stack and type <RET> to select it
(gdb-frames-select) and display the associated source in the
source buffer. Alternatively, click Mouse-2 on a frame to
select it. If the locals buffer is displayed then its contents update
to display the variables that are local to the new frame.
If you want to see how a variable changes each time your program stops
then place the cursor over the variable name and click on the watch
icon in the tool bar (gud-watch).
Each watch expression is displayed in the speedbar. Complex data types, such as arrays, structures and unions are represented in a tree format. Leaves and simple data types show the name of the expression and its value, and display the type as a tooltip. Higher levels show the name, type and address value for pointers and just the name and type otherwise.
To expand or contract a complex data type, click Mouse-2 on the tag to the left of the expression.
With the cursor over the root expression of a complex data type, type
D to delete it from the speedbar
(gdb-var-delete).
With the cursor over a simple data type or an element of a complex
data type which holds a value, type <RET> or click Mouse-2 to edit
its value. A prompt for a new value appears in the mini-buffer
(gdb-edit-value).
If you set the variable gdb-show-changed-values to
non-nil (the default value), Emacs will use
font-lock-warning-face to display values that have recently changed in
the speedbar.
If you set the variable gdb-use-colon-colon-notation to a
non-nil value then, in C, Emacs will use the
function::variable format to display variables in the
speedbar. Since this does not work for variables defined in compound
statements, the default value is nil.
gdb-use-inferior-io-buffer is non-nil,
the executable program that is being debugged takes its input and
displays its output here, otherwise it uses the GUD buffer. To toggle
the use of this buffer, do M-x gdb-use-inferior-io-buffer.
Some of the commands from shell mode are available here. See Shell Mode.
Arrays and structures display their type only. With GDB 6.4 or later,
move point to their name and press <RET>, or alternatively click
Mouse-2 there, to examine their values. With earlier versions
of GDB, move point to their type description ([struct/union] or
[array]). See Watch Expressions.
toggle-gdb-all-registers).
gdb-threads-select) and
display the associated source in the source buffer. Alternatively,
click Mouse-2 on a thread to select it. If the locals buffer is
displayed then its contents update to display the variables that are
local to the new thread.
Emacs has several different major modes for Lisp and Scheme. They are the same in terms of editing commands, but differ in the commands for executing Lisp expressions. Each mode has its own purpose.
Most editing commands for working with Lisp programs are in fact available globally. See Programs.
Lisp code for Emacs editing commands is stored in files whose names conventionally end in .el. This ending tells Emacs to edit them in Emacs-Lisp mode (see Executing Lisp).
To execute a file of Emacs Lisp code, use M-x load-file. This command reads a file name using the minibuffer and then executes the contents of that file as Lisp code. It is not necessary to visit the file first; in any case, this command reads the file as found on disk, not text in an Emacs buffer.
Once a file of Lisp code is installed in the Emacs Lisp library
directories, users can load it using M-x load-library. Programs can
load it by calling load-library, or with load, a more primitive
function that is similar but accepts some additional arguments.
M-x load-library differs from M-x load-file in that it searches a sequence of directories and tries three file names in each directory. Suppose your argument is lib; the three names are lib.elc, lib.el, and lastly just lib. If lib.elc exists, it is by convention the result of compiling lib.el; it is better to load the compiled file, since it will load and run faster.
If load-library finds that lib.el is newer than
lib.elc file, it issues a warning, because it's likely that
somebody made changes to the .el file and forgot to recompile
it.
Because the argument to load-library is usually not in itself
a valid file name, file name completion is not available. Indeed, when
using this command, you usually do not know exactly what file name
will be used.
The sequence of directories searched by M-x load-library is
specified by the variable load-path, a list of strings that are
directory names. The default value of the list contains the directory where
the Lisp code for Emacs itself is stored. If you have libraries of
your own, put them in a single directory and add that directory
to load-path. nil in this list stands for the current default
directory, but it is probably not a good idea to put nil in the
list. If you find yourself wishing that nil were in the list,
most likely what you really want to do is use M-x load-file
this once.
Often you do not have to give any command to load a library, because
the commands defined in the library are set up to autoload that
library. Trying to run any of those commands calls load to load
the library; this replaces the autoload definitions with the real ones
from the library.
Emacs Lisp code can be compiled into byte-code which loads faster,
takes up less space when loaded, and executes faster. See Byte Compilation.
By convention, the compiled code for a library goes in a separate file
whose name consists of the library source file with ‘c’ appended.
Thus, the compiled code for foo.el goes in foo.elc.
That's why load-library searches for ‘.elc’ files first.
By default, Emacs refuses to load compiled Lisp files which were
compiled with XEmacs, a modified versions of Emacs—they can cause
Emacs to crash. Set the variable load-dangerous-libraries to
t if you want to try loading them.
Lisp programs intended to be run in Emacs should be edited in Emacs-Lisp mode; this happens automatically for file names ending in .el. By contrast, Lisp mode itself is used for editing Lisp programs intended for other Lisp systems. To switch to Emacs-Lisp mode explicitly, use the command M-x emacs-lisp-mode.
For testing of Lisp programs to run in Emacs, it is often useful to evaluate part of the program as it is found in the Emacs buffer. For example, after changing the text of a Lisp function definition, evaluating the definition installs the change for future calls to the function. Evaluation of Lisp expressions is also useful in any kind of editing, for invoking noninteractive functions (functions that are not commands).
eval-expression).
eval-last-sexp).
eval-defun).
M-: (eval-expression) is the most basic command for evaluating
a Lisp expression interactively. It reads the expression using the
minibuffer, so you can execute any expression on a buffer regardless of
what the buffer contains. When the expression is evaluated, the current
buffer is once again the buffer that was current when M-: was
typed.
In Emacs-Lisp mode, the key C-M-x is bound to the command
eval-defun, which parses the defun containing or following point
as a Lisp expression and evaluates it. The value is printed in the echo
area. This command is convenient for installing in the Lisp environment
changes that you have just made in the text of a function definition.
C-M-x treats defvar expressions specially. Normally,
evaluating a defvar expression does nothing if the variable it
defines already has a value. But C-M-x unconditionally resets the
variable to the initial value specified in the defvar expression.
defcustom expressions are treated similarly.
This special feature is convenient for debugging Lisp programs.
Typing C-M-x on a defface expression reinitializes
the face according to the defface specification.
The command C-x C-e (eval-last-sexp) evaluates the Lisp
expression preceding point in the buffer, and displays the value in the
echo area. It is available in all major modes, not just Emacs-Lisp
mode. It does not treat defvar specially.
When the result of an evaluation is an integer, you can type C-x C-e a second time to display the value of the integer result in additional formats (octal, hexadecimal, and character).
If C-x C-e, or M-: is given a numeric argument, it inserts the value into the current buffer at point, rather than displaying it in the echo area. The argument's value does not matter. C-M-x with a numeric argument instruments the function definition for Edebug (see Instrumenting for Edebug).
The most general command for evaluating Lisp expressions from a buffer
is eval-region. M-x eval-region parses the text of the
region as one or more Lisp expressions, evaluating them one by one.
M-x eval-current-buffer is similar but evaluates the entire
buffer. This is a reasonable way to install the contents of a file of
Lisp code that you are ready to test. Later, as you find bugs and
change individual functions, use C-M-x on each function that you
change. This keeps the Lisp world in step with the source file.
The customizable variables eval-expression-print-level and
eval-expression-print-length control the maximum depth and length
of lists to print in the result of the evaluation commands before
abbreviating them. eval-expression-debug-on-error controls
whether evaluation errors invoke the debugger when these commands are
used.
The buffer ‘*scratch*’ which is selected when Emacs starts up is provided for evaluating Lisp expressions interactively inside Emacs.
The simplest way to use the ‘*scratch*’ buffer is to insert Lisp expressions and type C-j after each expression. This command reads the Lisp expression before point, evaluates it, and inserts the value in printed representation before point. The result is a complete typescript of the expressions you have evaluated and their values.
The ‘*scratch*’ buffer's major mode is Lisp Interaction mode, which is the same as Emacs-Lisp mode except for the binding of C-j.
The rationale for this feature is that Emacs must have a buffer when it starts up, but that buffer is not useful for editing files since a new buffer is made for every file that you visit. The Lisp interpreter typescript is the most useful thing I can think of for the initial buffer to do. Type M-x lisp-interaction-mode to put the current buffer in Lisp Interaction mode.
An alternative way of evaluating Emacs Lisp expressions interactively is to use Inferior Emacs-Lisp mode, which provides an interface rather like Shell mode (see Shell Mode) for evaluating Emacs Lisp expressions. Type M-x ielm to create an ‘*ielm*’ buffer which uses this mode.
Emacs has facilities for running programs in other Lisp systems. You can run a Lisp process as an inferior of Emacs, and pass expressions to it to be evaluated. You can also pass changed function definitions directly from the Emacs buffers in which you edit the Lisp programs to the inferior Lisp process.
To run an inferior Lisp process, type M-x run-lisp. This runs
the program named lisp, the same program you would run by typing
lisp as a shell command, with both input and output going through
an Emacs buffer named ‘*lisp*’. That is to say, any “terminal
output” from Lisp will go into the buffer, advancing point, and any
“terminal input” for Lisp comes from text in the buffer. (You can
change the name of the Lisp executable file by setting the variable
inferior-lisp-program.)
To give input to Lisp, go to the end of the buffer and type the input, terminated by <RET>. The ‘*lisp*’ buffer is in Inferior Lisp mode, which combines the special characteristics of Lisp mode with most of the features of Shell mode (see Shell Mode). The definition of <RET> to send a line to a subprocess is one of the features of Shell mode.
For the source files of programs to run in external Lisps, use Lisp mode. This mode can be selected with M-x lisp-mode, and is used automatically for files whose names end in .l, .lsp, or .lisp, as most Lisp systems usually expect.
When you edit a function in a Lisp program you are running, the easiest
way to send the changed definition to the inferior Lisp process is the key
C-M-x. In Lisp mode, this runs the function lisp-eval-defun,
which finds the defun around or following point and sends it as input to
the Lisp process. (Emacs can send input to any inferior process regardless
of what buffer is current.)
Contrast the meanings of C-M-x in Lisp mode (for editing programs to be run in another Lisp system) and Emacs-Lisp mode (for editing Lisp programs to be run in Emacs): in both modes it has the effect of installing the function definition that point is in, but the way of doing so is different according to where the relevant Lisp environment is found. See Executing Lisp.
This chapter describes Emacs features for maintaining programs. The version control features (see Version Control) are also particularly useful for this purpose.
The Emacs command C-x 4 a adds a new entry to the change log
file for the file you are editing
(add-change-log-entry-other-window). If that file is actually
a backup file, it makes an entry appropriate for the file's
parent—that is useful for making log entries for functions that
have been deleted in the current version.
A change log file contains a chronological record of when and why you have changed a program, consisting of a sequence of entries describing individual changes. Normally it is kept in a file called ChangeLog in the same directory as the file you are editing, or one of its parent directories. A single ChangeLog file can record changes for all the files in its directory and all its subdirectories.
You should put a copyright notice and permission notice at the end of the change log file. Here is an example:
Copyright 1997, 1998 Free Software Foundation, Inc.
Copying and distribution of this file, with or without modification, are
permitted provided the copyright notice and this notice are preserved.
Of course, you should substitute the proper years and copyright holder.
A change log entry starts with a header line that contains the current
date, your name, and your email address (taken from the variable
add-log-mailing-address). Aside from these header lines, every
line in the change log starts with a space or a tab. The bulk of the
entry consists of items, each of which starts with a line starting
with whitespace and a star. Here are two entries, both dated in May
1993, with two items and one item respectively.
1993-05-25 Richard Stallman <rms@gnu.org>
* man.el: Rename symbols `man-*' to `Man-*'.
(manual-entry): Make prompt string clearer.
* simple.el (blink-matching-paren-distance):
Change default to 12,000.
1993-05-24 Richard Stallman <rms@gnu.org>
* vc.el (minor-mode-map-alist): Don't use it if it's void.
(vc-cancel-version): Doc fix.
One entry can describe several changes; each change should have its own item, or its own line in an item. Normally there should be a blank line between items. When items are related (parts of the same change, in different places), group them by leaving no blank line between them.
C-x 4 a visits the change log file and creates a new entry unless the most recent entry is for today's date and your name. It also creates a new item for the current file. For many languages, it can even guess the name of the function or other object that was changed.
When the variable add-log-keep-changes-together is
non-nil, C-x 4 a adds to any existing item for the file
rather than starting a new item.
If the value of the variable change-log-version-info-enabled
is non-nil, C-x 4 a adds the file's version number to the
change log entry. It finds the version number by searching the first
ten percent of the file, using regular expressions from the variable
change-log-version-number-regexp-list.
If add-log-always-start-new-record is non-nil,
C-x 4 a always makes a new entry, even if the last entry
was made by you and on the same date.
The change log file is visited in Change Log mode. In this major mode, each bunch of grouped items counts as one paragraph, and each entry is considered a page. This facilitates editing the entries. C-j and auto-fill indent each new line like the previous line; this is convenient for entering the contents of an entry.
You can use the command M-x change-log-merge to merge other log files into a buffer in Change Log Mode, preserving the date ordering of entries.
Versions of Emacs before 20.1 used a different format for the time of the change log entry:
Fri May 25 11:23:23 1993 Richard Stallman <rms@gnu.org>
The M-x change-log-redate command converts all the old-style date entries in the change log file visited in the current buffer to the new format, to make the file uniform in style. This is handy when entries are contributed by many different people, some of whom use old versions of Emacs.
Version control systems are another way to keep track of changes in your program and keep a change log. See Log Buffer.
A tags table is a description of how a multi-file program is broken up into files. It lists the names of the component files and the names and positions of the functions (or other named subunits) in each file. Grouping the related files makes it possible to search or replace through all the files with one command. Recording the function names and positions makes possible the M-. command which finds the definition of a function by looking up which of the files it is in.
Tags tables are stored in files called tags table files. The conventional name for a tags table file is TAGS.
Each entry in the tags table records the name of one tag, the name of the
file that the tag is defined in (implicitly), and the position in that
file of the tag's definition. When a file parsed by etags is
generated from a different source file, like a C file generated from a
Cweb source file, the tags of the parsed file reference the source
file.
Just what names from the described files are recorded in the tags table depends on the programming language of the described file. They normally include all file names, functions and subroutines, and may also include global variables, data types, and anything else convenient. Each name recorded is called a tag.
See also the Ebrowse facility, which is tailored for C++. See Ebrowse.
Here is how tag syntax is defined for the most popular languages:
struct, union and enum.
#define macro definitions and enum constants are also
tags, unless you specify ‘--no-defines’ when making the tags table.
Similarly, global variables are tags, unless you specify
‘--no-globals’. Use of ‘--no-globals’ and ‘--no-defines’
can make the tags table file much smaller.
You can tag function declarations and external variables in addition
to function definitions by giving the ‘--declarations’ option to
etags. You can tag struct members with the ‘--members’
option.
operator definitions have
tag names like ‘operator+’.
interface, extends and implements constructs.
Tags for variables and functions in classes are named
‘class.variable’ and ‘class.function’.
\chapter,
\section, \subsection, \subsubsection,
\eqno, \label, \ref, \cite,
\bibitem, \part, \appendix, \entry,
\index, \def, \newcommand, \renewcommand,
\newenvironment or \renewenvironment is a tag.
Other commands can make tags as well, if you specify them in the
environment variable TEXTAGS before invoking etags. The
value of this environment variable should be a colon-separated list of
command names. For example,
TEXTAGS="mycommand:myothercommand"
export TEXTAGS
specifies (using Bourne shell syntax) that the commands ‘\mycommand’ and ‘\myothercommand’ also define tags.
defun, any variable
defined with defvar or defconst, and in general the first
argument of any expression that starts with ‘(def’ in column zero is
a tag.
def or with a
construct whose name starts with ‘def’. They also include variables
set with set! at top level in the file.
Several other languages are also supported:
In Ada, the same name can be used for different kinds of entity (e.g., for a procedure and for a function). Also, for things like packages, procedures and functions, there is the spec (i.e. the interface) and the body (i.e. the implementation). To make it easier to pick the definition you want, Ada tag name have suffixes indicating the type of entity:
Thus, M-x find-tag <RET> bidule/b <RET> will go
directly to the body of the package bidule, while M-x
find-tag <RET> bidule <RET> will just search for any tag
bidule.
title and the h1,
h2, h3 headers. Also, tags are name= in anchors
and all occurrences of id=.
package, sub, my and local
keywords. Use ‘--globals’ if you want to tag global variables.
Tags for subroutines are named ‘package::sub’. The
name for subroutines defined in the default package is
‘main::sub’.
def or class at the beginning of a line
generate a tag.
You can also generate tags based on regexp matching (see Etags Regexps) to handle other formats and languages.
The etags program is used to create a tags table file. It knows
the syntax of several languages, as described in
Here is how to run etags:
etags inputfiles...
The etags program reads the specified files, and writes a tags
table named TAGS in the current working directory.
If the specified files don't exist, etags looks for
compressed versions of them and uncompresses them to read them. Under
MS-DOS, etags also looks for file names like mycode.cgz
if it is given ‘mycode.c’ on the command line and mycode.c
does not exist.
etags recognizes the language used in an input file based on
its file name and contents. You can specify the language with the
‘--language=name’ option, described below.
If the tags table data become outdated due to changes in the files described in the table, the way to update the tags table is the same way it was made in the first place. If the tags table fails to record a tag, or records it for the wrong file, then Emacs cannot possibly find its definition until you update the tags table. However, if the position recorded in the tags table becomes a little bit wrong (due to other editing), the only consequence is a slight delay in finding the tag. Even if the stored position is very far wrong, Emacs will still find the tag, after searching most of the file for it. Even that delay is hardly noticeable with today's computers.
So you should update a tags table when you define new tags that you want to have listed, or when you move tag definitions from one file to another, or when changes become substantial. Normally there is no need to update the tags table after each edit, or even every day.
One tags table can virtually include another. Specify the included tags file name with the ‘--include=file’ option when creating the file that is to include it. The latter file then acts as if it covered all the source files specified in the included file, as well as the files it directly contains.
If you specify the source files with relative file names when you run
etags, the tags file will contain file names relative to the
directory where the tags file was initially written. This way, you can
move an entire directory tree containing both the tags file and the
source files, and the tags file will still refer correctly to the source
files. If the tags file is in /dev, however, the file names are
made relative to the current working directory.
If you specify absolute file names as arguments to etags, then
the tags file will contain absolute file names. This way, the tags file
will still refer to the same files even if you move it, as long as the
source files remain in the same place. Absolute file names start with
‘/’, or with ‘device:/’ on MS-DOS and MS-Windows.
When you want to make a tags table from a great number of files, you
may have problems listing them on the command line, because some systems
have a limit on its length. The simplest way to circumvent this limit
is to tell etags to read the file names from its standard input,
by typing a dash in place of the file names, like this:
find . -name "*.[chCH]" -print | etags -
Use the option ‘--language=name’ to specify the language
explicitly. You can intermix these options with file names; each one
applies to the file names that follow it. Specify
‘--language=auto’ to tell etags to resume guessing the
language from the file names and file contents. Specify
‘--language=none’ to turn off language-specific processing
entirely; then etags recognizes tags by regexp matching alone
(see Etags Regexps).
The option ‘--parse-stdin=file’ is mostly useful when
calling etags from programs. It can be used (only once) in
place of a file name on the command line. Etags will read from
standard input and mark the produced tags as belonging to the file
file.
‘etags --help’ prints the list of the languages etags
knows, and the file name rules for guessing the language. It also prints
a list of all the available etags options, together with a short
explanation. If followed by one or more ‘--language=lang’
options, prints detailed information about how tags are generated for
lang.
The ‘--regex’ option provides a general way of recognizing tags based on regexp matching. You can freely intermix it with file names. If you specify multiple ‘--regex’ options, all of them are used in parallel, but each one applies only to the source files that follow it. The syntax is:
--regex=[{language}]/tagregexp/[nameregexp/]modifiers
The essential part of the option value is tagregexp, the regexp for matching tags. It is always used anchored, that is, it only matches at the beginning of a line. If you want to allow indented tags, use a regexp that matches initial whitespace; start it with ‘[ \t]*’.
In these regular expressions, ‘\’ quotes the next character, and all the GCC character escape sequences are supported (‘\a’ for bell, ‘\b’ for back space, ‘\d’ for delete, ‘\e’ for escape, ‘\f’ for formfeed, ‘\n’ for newline, ‘\r’ for carriage return, ‘\t’ for tab, and ‘\v’ for vertical tab).
Ideally, tagregexp should not match more characters than are needed to recognize what you want to tag. If the syntax requires you to write tagregexp so it matches more characters beyond the tag itself, you should add a nameregexp, to pick out just the tag. This will enable Emacs to find tags more accurately and to do completion on tag names more reliably. You can find some examples below.
The modifiers are a sequence of zero or more characters that
modify the way etags does the matching. A regexp with no
modifiers is applied sequentially to each line of the input file, in a
case-sensitive way. The modifiers and their meanings are:
The ‘-R’ option cancels all the regexps defined by preceding ‘--regex’ options. It applies to the file names following it, as you can see from the following example:
etags --regex=/reg1/i voo.doo --regex=/reg2/m \
bar.ber -R --lang=lisp los.er
Here etags chooses the parsing language for voo.doo and
bar.ber according to their contents. etags also uses
reg1 to recognize additional tags in voo.doo, and both
reg1 and reg2 to recognize additional tags in
bar.ber. reg1 is checked against each line of
voo.doo and bar.ber, in a case-insensitive way, while
reg2 is checked against the whole bar.ber file,
permitting multi-line matches, in a case-sensitive way. etags
uses only the Lisp tags rules, with no user-specified regexp matching,
to recognize tags in los.er.
You can restrict a ‘--regex’ option to match only files of a
given language by using the optional prefix {language}.
(‘etags --help’ prints the list of languages recognized by
etags.) This is particularly useful when storing many
predefined regular expressions for etags in a file. The
following example tags the DEFVAR macros in the Emacs source
files, for the C language only:
--regex='{c}/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/'
When you have complex regular expressions, you can store the list of
them in a file. The following option syntax instructs etags to
read two files of regular expressions. The regular expressions
contained in the second file are matched without regard to case.
--regex=@case-sensitive-file --ignore-case-regex=@ignore-case-file
A regex file for etags contains one regular expression per
line. Empty lines, and lines beginning with space or tab are ignored.
When the first character in a line is ‘@’, etags assumes
that the rest of the line is the name of another file of regular
expressions; thus, one such file can include another file. All the
other lines are taken to be regular expressions. If the first
non-whitespace text on the line is ‘--’, that line is a comment.
For example, we can create a file called ‘emacs.tags’ with the following contents:
-- This is for GNU Emacs C source files
{c}/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/\1/
and then use it like this:
etags --regex=@emacs.tags *.[ch] */*.[ch]
Here are some more examples. The regexps are quoted to protect them from shell interpretation.
etags --language=none \
--regex='/[ \t]*function.*=[ \t]*\([^ \t]*\)[ \t]*(/\1/' \
--regex='/###key \(.*\)/\1/' \
--regex='/[ \t]*global[ \t].*/' \
*.m
Note that tags are not generated for scripts, so that you have to add a line by yourself of the form ‘###key scriptname’ if you want to jump to it.
etags --language=none --regex='/proc[ \t]+\([^ \t]+\)/\1/' *.tcl
etags --language=none \
--regex='/[ \t]*\(ARCHITECTURE\|CONFIGURATION\) +[^ ]* +OF/' \
--regex='/[ \t]*\(ATTRIBUTE\|ENTITY\|FUNCTION\|PACKAGE\
\( BODY\)?\|PROCEDURE\|PROCESS\|TYPE\)[ \t]+\([^ \t(]+\)/\3/'
Emacs has at any time one selected tags table, and all the commands for working with tags tables use the selected one. To select a tags table, type M-x visit-tags-table, which reads the tags table file name as an argument. The name TAGS in the default directory is used as the default file name.
All this command does is store the file name in the variable
tags-file-name. Emacs does not actually read in the tags table
contents until you try to use them. Setting this variable yourself is just
as good as using visit-tags-table. The variable's initial value is
nil; that value tells all the commands for working with tags tables
that they must ask for a tags table file name to use.
Using visit-tags-table when a tags table is already loaded
gives you a choice: you can add the new tags table to the current list
of tags tables, or start a new list. The tags commands use all the tags
tables in the current list. If you start a new list, the new tags table
is used instead of others. If you add the new table to the
current list, it is used as well as the others. When the tags
commands scan the list of tags tables, they don't always start at the
beginning of the list; they start with the first tags table (if any)
that describes the current file, proceed from there to the end of the
list, and then scan from the beginning of the list until they have
covered all the tables in the list.
You can specify a precise list of tags tables by setting the variable
tags-table-list to a list of strings, like this:
(setq tags-table-list
'("~/emacs" "/usr/local/lib/emacs/src"))
This tells the tags commands to look at the TAGS files in your ~/emacs directory and in the /usr/local/lib/emacs/src directory. The order depends on which file you are in and which tags table mentions that file, as explained above.
Do not set both tags-file-name and tags-table-list.
The most important thing that a tags table enables you to do is to find the definition of a specific tag.
find-tag).
find-tag-regexp).
find-tag-other-window).
find-tag-other-frame).
M-. (find-tag) is the command to find the definition of
a specified tag. It searches through the tags table for that tag, as a
string, and then uses the tags table info to determine the file that the
definition is in and the approximate character position in the file of
the definition. Then find-tag visits that file, moves point to
the approximate character position, and searches ever-increasing
distances away to find the tag definition.
If an empty argument is given (just type <RET>), the balanced expression in the buffer before or around point is used as the tag argument. See Expressions.
You don't need to give M-. the full name of the tag; a part
will do. This is because M-. finds tags in the table which
contain tag as a substring. However, it prefers an exact match
to a substring match. To find other tags that match the same
substring, give find-tag a numeric argument, as in C-u
M-.; this does not read a tag name, but continues searching the tags
table's text for another tag containing the same substring last used.
If you have a real <META> key, M-0 M-. is an easier
alternative to C-u M-..
Like most commands that can switch buffers, find-tag has a
variant that displays the new buffer in another window, and one that
makes a new frame for it. The former is C-x 4 ., which invokes
the command find-tag-other-window. The latter is C-x 5 .,
which invokes find-tag-other-frame.
To move back to places you've found tags recently, use C-u - M-.; more generally, M-. with a negative numeric argument. This command can take you to another buffer. C-x 4 . with a negative argument finds the previous tag location in another window.
As well as going back to places you've found tags recently, you can go
back to places from where you found them. Use M-*, which
invokes the command pop-tag-mark, for this. Typically you would
find and study the definition of something with M-. and then
return to where you were with M-*.
Both C-u - M-. and M-* allow you to retrace your steps to
a depth determined by the variable find-tag-marker-ring-length.
The command C-M-. (find-tag-regexp) visits the tags that
match a specified regular expression. It is just like M-. except
that it does regexp matching instead of substring matching.
The commands in this section visit and search all the files listed in the selected tags table, one by one. For these commands, the tags table serves only to specify a sequence of files to search.
query-replace-regexp on each file in the selected tags table.
tags-loop-continue).
M-x tags-search reads a regexp using the minibuffer, then
searches for matches in all the files in the selected tags table, one
file at a time. It displays the name of the file being searched so you
can follow its progress. As soon as it finds an occurrence,
tags-search returns.
Having found one match, you probably want to find all the rest. To find
one more match, type M-, (tags-loop-continue) to resume the
tags-search. This searches the rest of the current buffer, followed
by the remaining files of the tags table.
M-x tags-query-replace performs a single
query-replace-regexp through all the files in the tags table. It
reads a regexp to search for and a string to replace with, just like
ordinary M-x query-replace-regexp. It searches much like M-x
tags-search, but repeatedly, processing matches according to your
input. See Replace, for more information on query replace.
You can control the case-sensitivity of tags search commands by
customizing the value of the variable tags-case-fold-search. The
default is to use the same setting as the value of
case-fold-search (see Search Case).
It is possible to get through all the files in the tags table with a single invocation of M-x tags-query-replace. But often it is useful to exit temporarily, which you can do with any input event that has no special query replace meaning. You can resume the query replace subsequently by typing M-,; this command resumes the last tags search or replace command that you did.
The commands in this section carry out much broader searches than the
find-tag family. The find-tag commands search only for
definitions of tags that match your substring or regexp. The commands
tags-search and tags-query-replace find every occurrence
of the regexp, as ordinary search commands and replace commands do in
the current buffer.
These commands create buffers only temporarily for the files that they have to search (those which are not already visited in Emacs buffers). Buffers in which no match is found are quickly killed; the others continue to exist.
It may have struck you that tags-search is a lot like
grep. You can also run grep itself as an inferior of
Emacs and have Emacs show you the matching lines one by one. This works
much like running a compilation; finding the source locations of the
grep matches works like finding the compilation errors.
See Grep Searching.
M-x list-tags reads the name of one of the files described by the selected tags table, and displays a list of all the tags defined in that file. The “file name” argument is really just a string to compare against the file names recorded in the tags table; it is read as a string rather than as a file name. Therefore, completion and defaulting are not available, and you must enter the file name the same way it appears in the tags table. Do not include a directory as part of the file name unless the file name recorded in the tags table includes a directory.
M-x tags-apropos is like apropos for tags
(see Apropos). It finds all the tags in the selected tags table
whose entries match regexp, and displays them. If the variable
tags-apropos-verbose is non-nil, it displays the names
of the tags files together with the tag names.
You can customize the appearance of the output with the face
tags-tag-face. You can display additional output with M-x
tags-apropos by customizing the variable
tags-apropos-additional-actions—see its documentation for
details.
You can also use the collection of tag names to complete a symbol name in the buffer. See Symbol Completion.
It's not unusual for programmers to get their signals crossed and modify the same program in two different directions. To recover from this confusion, you need to merge the two versions. Emerge makes this easier. See also Comparing Files, for commands to compare in a more manual fashion, and Ediff.
To start Emerge, run one of these four commands:
The Emerge commands compare two files or buffers, and display the comparison in three buffers: one for each input text (the A buffer and the B buffer), and one (the merge buffer) where merging takes place. The merge buffer shows the full merged text, not just the differences. Wherever the two input texts differ, you can choose which one of them to include in the merge buffer.
The Emerge commands that take input from existing buffers use only the accessible portions of those buffers, if they are narrowed (see Narrowing).
If a common ancestor version is available, from which the two texts to be merged were both derived, Emerge can use it to guess which alternative is right. Wherever one current version agrees with the ancestor, Emerge presumes that the other current version is a deliberate change which should be kept in the merged version. Use the ‘with-ancestor’ commands if you want to specify a common ancestor text. These commands read three file or buffer names—variant A, variant B, and the common ancestor.
After the comparison is done and the buffers are prepared, the interactive merging starts. You control the merging by typing special merge commands in the merge buffer (see Merge Commands). For each run of differences between the input texts, you can choose which one of them to keep, or edit them both together.
The merge buffer uses a special major mode, Emerge mode, with commands for making these choices. But you can also edit the buffer with ordinary Emacs commands.
At any given time, the attention of Emerge is focused on one particular difference, called the selected difference. This difference is marked off in the three buffers like this:
vvvvvvvvvvvvvvvvvvvv
text that differs
^^^^^^^^^^^^^^^^^^^^
Emerge numbers all the differences sequentially and the mode line always shows the number of the selected difference.
Normally, the merge buffer starts out with the A version of the text. But when the A version of a difference agrees with the common ancestor, then the B version is initially preferred for that difference.
Emerge leaves the merged text in the merge buffer when you exit. At
that point, you can save it in a file with C-x C-w. If you give a
numeric argument to emerge-files or
emerge-files-with-ancestor, it reads the name of the output file
using the minibuffer. (This is the last file name those commands read.)
Then exiting from Emerge saves the merged text in the output file.
Normally, Emerge commands save the output buffer in its file when you exit. If you abort Emerge with C-], the Emerge command does not save the output buffer, but you can save it yourself if you wish.
You can choose between two modes for giving merge commands: Fast mode and Edit mode. In Fast mode, basic merge commands are single characters, but ordinary Emacs commands are disabled. This is convenient if you use only merge commands. In Edit mode, all merge commands start with the prefix key C-c C-c, and the normal Emacs commands are also available. This allows editing the merge buffer, but slows down Emerge operations.
Use e to switch to Edit mode, and C-c C-c f to switch to Fast mode. The mode line indicates Edit and Fast modes with ‘E’ and ‘F’.
Emerge has two additional submodes that affect how particular merge commands work: Auto Advance mode and Skip Prefers mode.
If Auto Advance mode is in effect, the a and b commands advance to the next difference. This lets you go through the merge faster as long as you simply choose one of the alternatives from the input. The mode line indicates Auto Advance mode with ‘A’.
If Skip Prefers mode is in effect, the n and p commands skip over differences in states prefer-A and prefer-B (see State of Difference). Thus you see only differences for which neither version is presumed “correct.” The mode line indicates Skip Prefers mode with ‘S’.
Use the command s a (emerge-auto-advance-mode) to set or
clear Auto Advance mode. Use s s
(emerge-skip-prefers-mode) to set or clear Skip Prefers mode.
These commands turn on the mode with a positive argument, turns it off
with a negative or zero argument, and toggle the mode with no argument.
In the merge buffer, a difference is marked with lines of ‘v’ and ‘^’ characters. Each difference has one of these seven states:
When you select a difference, its state changes from default-A or default-B to plain A or B. Thus, the selected difference never has state default-A or default-B, and these states are never displayed in the mode line.
The command d a chooses default-A as the default state, and d
b chooses default-B. This chosen default applies to all differences
which you haven't ever selected and for which no alternative is preferred.
If you are moving through the merge sequentially, the differences you
haven't selected are those following the selected one. Thus, while
moving sequentially, you can effectively make the A version the default
for some sections of the merge buffer and the B version the default for
others by using d a and d b between sections.
These two states are displayed in the mode line as ‘A*’ and ‘B*’.
Once a difference is in this state, the a and b commands don't do anything to it unless you give them a numeric argument.
The mode line displays this state as ‘comb’.
Here are the Merge commands for Fast mode; in Edit mode, precede them with C-c C-c:
The q command (emerge-quit) finishes the merge, storing
the results into the output file if you specified one. It restores the
A and B buffers to their proper contents, or kills them if they were
created by Emerge and you haven't changed them. It also disables the
Emerge commands in the merge buffer, since executing them later could
damage the contents of the various buffers.
C-] aborts the merge. This means exiting without writing the output file. If you didn't specify an output file, then there is no real difference between aborting and finishing the merge.
If the Emerge command was called from another Lisp program, then its
return value is t for successful completion, or nil if you
abort.
Sometimes you want to keep both alternatives for a particular difference. To do this, use x c, which edits the merge buffer like this:
#ifdef NEW
version from A buffer
#else /* not NEW */
version from B buffer
#endif /* not NEW */
While this example shows C preprocessor conditionals delimiting the two
alternative versions, you can specify the strings to use by setting
the variable emerge-combine-versions-template to a string of your
choice. In the string, ‘%a’ says where to put version A, and
‘%b’ says where to put version B. The default setting, which
produces the results shown above, looks like this:
"#ifdef NEW\n%a#else /* not NEW */\n%b#endif /* not NEW */\n"
During the merge, you mustn't try to edit the A and B buffers yourself. Emerge modifies them temporarily, but ultimately puts them back the way they were.
You can have any number of merges going at once—just don't use any one buffer as input to more than one merge at once, since the temporary changes made in these buffers would get in each other's way.
Starting Emerge can take a long time because it needs to compare the
files fully. Emacs can't do anything else until diff finishes.
Perhaps in the future someone will change Emerge to do the comparison in
the background when the input files are large—then you could keep on
doing other things with Emacs until Emerge is ready to accept
commands.
After setting up the merge, Emerge runs the hook
emerge-startup-hook (see Hooks).
A defined abbrev is a word which expands, if you insert it, into some different text. Abbrevs are defined by the user to expand in specific ways. For example, you might define ‘foo’ as an abbrev expanding to ‘find outer otter’. Then you would be able to insert ‘find outer otter ’ into the buffer by typing f o o <SPC>.
A second kind of abbreviation facility is called dynamic abbrev expansion. You use dynamic abbrev expansion with an explicit command to expand the letters in the buffer before point by looking for other words in the buffer that start with those letters. See Dynamic Abbrevs.
“Hippie” expansion generalizes abbreviation expansion. See Hippie Expansion.
An abbrev is a word which has been defined to expand into a specified expansion. When you insert a word-separator character following the abbrev, that expands the abbrev—replacing the abbrev with its expansion. For example, if ‘foo’ is defined as an abbrev expanding to ‘find outer otter’, then you can insert ‘find outer otter.’ into the buffer by typing f o o ..
Abbrevs expand only when Abbrev mode (a minor mode) is enabled.
Disabling Abbrev mode does not cause abbrev definitions to be forgotten,
but they do not expand until Abbrev mode is enabled again. The command
M-x abbrev-mode toggles Abbrev mode; with a numeric argument, it
turns Abbrev mode on if the argument is positive, off otherwise.
See Minor Modes. abbrev-mode is also a variable; Abbrev mode is
on when the variable is non-nil. The variable abbrev-mode
automatically becomes local to the current buffer when it is set.
Abbrev definitions can be mode-specific—active only in one major mode. Abbrevs can also have global definitions that are active in all major modes. The same abbrev can have a global definition and various mode-specific definitions for different major modes. A mode-specific definition for the current major mode overrides a global definition.
Abbrevs can be defined interactively during the editing session. Lists of abbrev definitions can also be saved in files and reloaded in later sessions. Some users keep extensive lists of abbrevs that they load in every session.
add-global-abbrev).
add-mode-abbrev).
inverse-add-global-abbrev).
inverse-add-mode-abbrev).
The usual way to define an abbrev is to enter the text you want the
abbrev to expand to, position point after it, and type C-x a g
(add-global-abbrev). This reads the abbrev itself using the
minibuffer, and then defines it as an abbrev for one or more words before
point. Use a numeric argument to say how many words before point should be
taken as the expansion. For example, to define the abbrev ‘foo’ as
mentioned above, insert the text ‘find outer otter’ and then type
C-u 3 C-x a g f o o <RET>.
An argument of zero to C-x a g means to use the contents of the region as the expansion of the abbrev being defined.
The command C-x a l (add-mode-abbrev) is similar, but
defines a mode-specific abbrev. Mode-specific abbrevs are active only in a
particular major mode. C-x a l defines an abbrev for the major mode
in effect at the time C-x a l is typed. The arguments work the same
as for C-x a g.
If the text already in the buffer is the abbrev, rather than its
expansion, use command C-x a i g
(inverse-add-global-abbrev) instead of C-x a g, or use
C-x a i l (inverse-add-mode-abbrev) instead of C-x a
l. These commands are called “inverse” because they invert the
meaning of the two text strings they use (one from the buffer and one
read with the minibuffer).
You can define an abbrev without inserting either the abbrev or its
expansion in the buffer using the command define-global-abbrev.
It reads two arguments—the abbrev, and its expansion. The command
define-mode-abbrev does likewise for a mode-specific abbrev.
To change the definition of an abbrev, just define a new definition. When the abbrev has a prior definition, the abbrev definition commands ask for confirmation before replacing it.
To remove an abbrev definition, give a negative argument to the abbrev definition command: C-u - C-x a g or C-u - C-x a l. The former removes a global definition, while the latter removes a mode-specific definition.
M-x kill-all-abbrevs removes all the abbrev definitions there are, both global and local.
An abbrev expands whenever it is present in the buffer just before point and you type a self-inserting whitespace or punctuation character (<SPC>, comma, etc.). More precisely, any character that is not a word constituent expands an abbrev, and any word-constituent character can be part of an abbrev. The most common way to use an abbrev is to insert it and then insert a punctuation or whitespace character to expand it.
Abbrev expansion preserves case; thus, ‘foo’ expands into ‘find
outer otter’; ‘Foo’ into ‘Find outer otter’, and ‘FOO’ into
‘FIND OUTER OTTER’ or ‘Find Outer Otter’ according to the
variable abbrev-all-caps (setting it non-nil specifies
‘FIND OUTER OTTER’).
These commands are used to control abbrev expansion:
abbrev-prefix-mark).
expand-abbrev).
This is effective even when Abbrev mode is not enabled.
You may wish to expand an abbrev with a prefix attached; for example,
if ‘cnst’ expands into ‘construction’, you might want to use
it to enter ‘reconstruction’. It does not work to type
recnst, because that is not necessarily a defined abbrev. What
you can do is use the command M-' (abbrev-prefix-mark) in
between the prefix ‘re’ and the abbrev ‘cnst’. First, insert
‘re’. Then type M-'; this inserts a hyphen in the buffer to
indicate that it has done its work. Then insert the abbrev ‘cnst’;
the buffer now contains ‘re-cnst’. Now insert a non-word character
to expand the abbrev ‘cnst’ into ‘construction’. This
expansion step also deletes the hyphen that indicated M-' had been
used. The result is the desired ‘reconstruction’.
If you actually want the text of the abbrev in the buffer, rather than its expansion, you can accomplish this by inserting the following punctuation with C-q. Thus, foo C-q , leaves ‘foo,’ in the buffer.
If you expand an abbrev by mistake, you can undo the expansion and bring back the abbrev itself by typing C-_ to undo (see Undo). This also undoes the insertion of the non-word character that expanded the abbrev. If the result you want is the terminating non-word character plus the unexpanded abbrev, you must reinsert the terminating character, quoting it with C-q. You can also use the command M-x unexpand-abbrev to cancel the last expansion without deleting the terminating character.
M-x expand-region-abbrevs searches through the region for defined abbrevs, and for each one found offers to replace it with its expansion. This command is useful if you have typed in text using abbrevs but forgot to turn on Abbrev mode first. It may also be useful together with a special set of abbrev definitions for making several global replacements at once. This command is effective even if Abbrev mode is not enabled.
Expanding an abbrev runs the hook pre-abbrev-expand-hook
(see Hooks).
The output from M-x list-abbrevs looks like this:
(lisp-mode-abbrev-table)
"dk" 0 "define-key"
(global-abbrev-table)
"dfn" 0 "definition"
(Some blank lines of no semantic significance, and some other abbrev tables, have been omitted.)
A line containing a name in parentheses is the header for abbrevs in a
particular abbrev table; global-abbrev-table contains all the global
abbrevs, and the other abbrev tables that are named after major modes
contain the mode-specific abbrevs.
Within each abbrev table, each nonblank line defines one abbrev. The word at the beginning of the line is the abbrev. The number that follows is the number of times the abbrev has been expanded. Emacs keeps track of this to help you see which abbrevs you actually use, so that you can eliminate those that you don't use often. The string at the end of the line is the expansion.
M-x edit-abbrevs allows you to add, change or kill abbrev definitions by editing a list of them in an Emacs buffer. The list has the same format described above. The buffer of abbrevs is called ‘*Abbrevs*’, and is in Edit-Abbrevs mode. Type C-c C-c in this buffer to install the abbrev definitions as specified in the buffer—and delete any abbrev definitions not listed.
The command edit-abbrevs is actually the same as
list-abbrevs except that it selects the buffer ‘*Abbrevs*’
whereas list-abbrevs merely displays it in another window.
These commands allow you to keep abbrev definitions between editing sessions.
M-x write-abbrev-file reads a file name using the minibuffer and then writes a description of all current abbrev definitions into that file. This is used to save abbrev definitions for use in a later session. The text stored in the file is a series of Lisp expressions that, when executed, define the same abbrevs that you currently have.
M-x read-abbrev-file reads a file name using the minibuffer
and then reads the file, defining abbrevs according to the contents of
the file. The function quietly-read-abbrev-file is similar
except that it does not display a message in the echo area; you cannot
invoke it interactively, and it is used primarily in the .emacs
file. If either of these functions is called with nil as the
argument, it uses the file name specified in the variable
abbrev-file-name, which is by default "~/.abbrev_defs".
That file is your standard abbrev definition file, and Emacs loads
abbrevs from it automatically when it starts up.
Emacs will offer to save abbrevs automatically if you have changed
any of them, whenever it offers to save all files (for C-x s or
C-x C-c). It saves them in the file specified by
abbrev-file-name. This feature can be inhibited by setting the
variable save-abbrevs to nil.
The commands M-x insert-abbrevs and M-x define-abbrevs are similar to the previous commands but work on text in an Emacs buffer. M-x insert-abbrevs inserts text into the current buffer after point, describing all current abbrev definitions; M-x define-abbrevs parses the entire current buffer and defines abbrevs accordingly.
The abbrev facility described above operates automatically as you insert text, but all abbrevs must be defined explicitly. By contrast, dynamic abbrevs allow the meanings of abbrevs to be determined automatically from the contents of the buffer, but dynamic abbrev expansion happens only when you request it explicitly.
dabbrev-expand).
dabbrev-completion).
For example, if the buffer contains ‘does this follow ’ and you
type f o M-/, the effect is to insert ‘follow’ because that
is the last word in the buffer that starts with ‘fo’. A numeric
argument to M-/ says to take the second, third, etc. distinct
expansion found looking backward from point. Repeating M-/
searches for an alternative expansion by looking farther back. After
scanning all the text before point, it searches the text after point.
The variable dabbrev-limit, if non-nil, specifies how far
in the buffer to search for an expansion.
After scanning the current buffer, M-/ normally searches other
buffers, unless you have set dabbrev-check-all-buffers to
nil.
For finer control over which buffers to scan, customize the variable
dabbrev-ignored-buffer-regexps. Its value is a list of regular
expressions. If a buffer's name matches any of these regular
expressions, dynamic abbrev expansion skips that buffer.
A negative argument to M-/, as in C-u - M-/, says to search first for expansions after point, then other buffers, and consider expansions before point only as a last resort.
If you repeat the M-/ to look for another expansion, do not specify an argument. This tries all the expansions after point and then the expansions before point.
After you have expanded a dynamic abbrev, you can copy additional words that follow the expansion in its original context. Simply type <SPC> M-/ for each word you want to copy. The spacing and punctuation between words is copied along with the words.
The command C-M-/ (dabbrev-completion) performs
completion of a dynamic abbreviation. Instead of trying the possible
expansions one by one, it finds all of them, then inserts the text that
they have in common. If they have nothing in common, C-M-/
displays a list of completions, from which you can select a choice in
the usual manner. See Completion.
Dynamic abbrev expansion is completely independent of Abbrev mode; the expansion of a word with M-/ is completely independent of whether it has a definition as an ordinary abbrev.
Normally, dynamic abbrev expansion ignores case when searching for expansions. That is, the expansion need not agree in case with the word you are expanding.
This feature is controlled by the variable
dabbrev-case-fold-search. If it is t, case is ignored in
this search; if it is nil, the word and the expansion must match
in case. If the value of dabbrev-case-fold-search is
case-fold-search, which is true by default, then the variable
case-fold-search controls whether to ignore case while searching
for expansions.
Normally, dynamic abbrev expansion preserves the case pattern of the abbrev you have typed, by converting the expansion to that case pattern.
The variable dabbrev-case-replace controls whether to preserve
the case pattern of the abbrev. If it is t, the abbrev's case
pattern is preserved in most cases; if it is nil, the expansion is
always copied verbatim. If the value of dabbrev-case-replace is
case-replace, which is true by default, then the variable
case-replace controls whether to copy the expansion verbatim.
However, if the expansion contains a complex mixed case pattern, and
the abbrev matches this pattern as far as it goes, then the expansion is
always copied verbatim, regardless of those variables. Thus, for
example, if the buffer contains variableWithSillyCasePattern, and
you type v a M-/, it copies the expansion verbatim including its
case pattern.
The variable dabbrev-abbrev-char-regexp, if non-nil,
controls which characters are considered part of a word, for dynamic expansion
purposes. The regular expression must match just one character, never
two or more. The same regular expression also determines which
characters are part of an expansion. The value nil has a special
meaning: abbreviations are made of word characters, but expansions are
made of word and symbol characters.
In shell scripts and makefiles, a variable name is sometimes prefixed
with ‘$’ and sometimes not. Major modes for this kind of text can
customize dynamic abbreviation to handle optional prefixes by setting
the variable dabbrev-abbrev-skip-leading-regexp. Its value
should be a regular expression that matches the optional prefix that
dynamic abbreviation should ignore.
To edit a picture made out of text characters (for example, a picture of the division of a register into fields, as a comment in a program), use the command M-x edit-picture to enter Picture mode.
In Picture mode, editing is based on the quarter-plane model of text, according to which the text characters lie studded on an area that stretches infinitely far to the right and downward. The concept of the end of a line does not exist in this model; the most you can say is where the last nonblank character on the line is found.
Of course, Emacs really always considers text as a sequence of characters, and lines really do have ends. But Picture mode replaces the most frequently-used commands with variants that simulate the quarter-plane model of text. They do this by inserting spaces or by converting tabs to spaces.
Most of the basic editing commands of Emacs are redefined by Picture mode to do essentially the same thing but in a quarter-plane way. In addition, Picture mode defines various keys starting with the C-c prefix to run special picture editing commands.
One of these keys, C-c C-c, is pretty important. Often a
picture is part of a larger file that is usually edited in some other
major mode. M-x edit-picture records the name of the previous
major mode so you can use the C-c C-c command
(picture-mode-exit) later to go back to that mode. C-c C-c
also deletes spaces from the ends of lines, unless given a numeric
argument.
The special commands of Picture mode all work in other modes (provided the picture library is loaded), but are not bound to keys except in Picture mode. The descriptions below talk of moving “one column” and so on, but all the picture mode commands handle numeric arguments as their normal equivalents do.
Turning on Picture mode runs the hook picture-mode-hook
(see Hooks). Additional extensions to Picture mode can be found
in artist.el.
Most keys do the same thing in Picture mode that they usually do, but
do it in a quarter-plane style. For example, C-f is rebound to
run picture-forward-column, a command which moves point one
column to the right, inserting a space if necessary so that the actual
end of the line makes no difference. C-b is rebound to run
picture-backward-column, which always moves point left one
column, converting a tab to multiple spaces if necessary. C-n and
C-p are rebound to run picture-move-down and
picture-move-up, which can either insert spaces or convert tabs
as necessary to make sure that point stays in exactly the same column.
C-e runs picture-end-of-line, which moves to after the last
nonblank character on the line. There is no need to change C-a,
as the choice of screen model does not affect beginnings of
lines.
Insertion of text is adapted to the quarter-plane screen model through
the use of Overwrite mode (see Minor Modes). Self-inserting characters
replace existing text, column by column, rather than pushing existing text
to the right. <RET> runs picture-newline, which just moves to
the beginning of the following line so that new text will replace that
line.
In Picture mode, the commands that normally delete or kill text,
instead erase text (replacing it with spaces). <DEL>
(picture-backward-clear-column) replaces the preceding
character with a space rather than removing it; this moves point
backwards. C-d (picture-clear-column) replaces the next
character or characters with spaces, but does not move point. (If you
want to clear characters to spaces and move forward over them, use
<SPC>.) C-k (picture-clear-line) really kills the
contents of lines, but does not delete the newlines from the buffer.
To do actual insertion, you must use special commands. C-o
(picture-open-line) creates a blank line after the current
line; it never splits a line. C-M-o (split-line) makes
sense in Picture mode, so it is not changed. C-j
(picture-duplicate-line) inserts another line with the same
contents below the current line.
To do actual deletion in Picture mode, use C-w, C-c C-d
(which is defined as delete-char, as C-d is in other
modes), or one of the picture rectangle commands (see Rectangles in Picture).
Since “self-inserting” characters in Picture mode overwrite and move point, there is no essential restriction on how point should be moved. Normally point moves right, but you can specify any of the eight orthogonal or diagonal directions for motion after a “self-inserting” character. This is useful for drawing lines in the buffer.
picture-movement-left).
picture-movement-right).
picture-movement-up).
picture-movement-down).
picture-movement-nw).
picture-movement-ne).
picture-movement-sw).
picture-movement-se).
Two motion commands move based on the current Picture insertion
direction. The command C-c C-f (picture-motion) moves in the
same direction as motion after “insertion” currently does, while C-c
C-b (picture-motion-reverse) moves in the opposite direction.
Two kinds of tab-like action are provided in Picture mode. Use
M-<TAB> (picture-tab-search) for context-based tabbing.
With no argument, it moves to a point underneath the next
“interesting” character that follows whitespace in the previous
nonblank line. “Next” here means “appearing at a horizontal position
greater than the one point starts out at.” With an argument, as in
C-u M-<TAB>, this command moves to the next such interesting
character in the current line. M-<TAB> does not change the
text; it only moves point. “Interesting” characters are defined by
the variable picture-tab-chars, which should define a set of
characters. The syntax for this variable is like the syntax used inside
of ‘[...]’ in a regular expression—but without the ‘[’
and the ‘]’. Its default value is "!-~".
<TAB> itself runs picture-tab, which operates based on the
current tab stop settings; it is the Picture mode equivalent of
tab-to-tab-stop. Normally it just moves point, but with a numeric
argument it clears the text that it moves over.
The context-based and tab-stop-based forms of tabbing are brought
together by the command C-c <TAB> (picture-set-tab-stops).
This command sets the tab stops to the positions which M-<TAB>
would consider significant in the current line. The use of this command,
together with <TAB>, can get the effect of context-based tabbing. But
M-<TAB> is more convenient in the cases where it is sufficient.
It may be convenient to prevent use of actual tab characters in
pictures. For example, this prevents C-x <TAB> from messing
up the picture. You can do this by setting the variable
indent-tabs-mode to nil. See Just Spaces.
Picture mode defines commands for working on rectangular pieces of the text in ways that fit with the quarter-plane model. The standard rectangle commands may also be useful (see Rectangles).
picture-clear-rectangle). With argument, delete the text.
picture-clear-rectangle-to-register).
picture-yank-rectangle). With argument,
insert instead.
picture-yank-rectangle-from-register).
The picture rectangle commands C-c C-k
(picture-clear-rectangle) and C-c C-w
(picture-clear-rectangle-to-register) differ from the standard
rectangle commands in that they normally clear the rectangle instead of
deleting it; this is analogous with the way C-d is changed in Picture
mode.
However, deletion of rectangles can be useful in Picture mode, so these commands delete the rectangle if given a numeric argument. C-c C-k either with or without a numeric argument saves the rectangle for C-c C-y.
The Picture mode commands for yanking rectangles differ from the
standard ones in that they overwrite instead of inserting. This is
the same way that Picture mode insertion of other text differs from
other modes. C-c C-y (picture-yank-rectangle) inserts
(by overwriting) the rectangle that was most recently killed, while
C-c C-x (picture-yank-rectangle-from-register) does
likewise for the rectangle found in a specified register.
To send a message in Emacs, you start by typing a command (C-x m) to select and initialize the ‘*mail*’ buffer. Then you edit the text and headers of the message in this buffer, and type another command (C-c C-s or C-c C-c) to send the message.
compose-mail).
compose-mail-other-window).
compose-mail-other-frame).
mail-send).
mail-send-and-exit).
The command C-x m (compose-mail) selects a buffer named
‘*mail*’ and initializes it with the skeleton of an outgoing
message. C-x 4 m (compose-mail-other-window) selects the
‘*mail*’ buffer in a different window, leaving the previous current
buffer visible. C-x 5 m (compose-mail-other-frame) creates
a new frame to select the ‘*mail*’ buffer.
Because the mail-composition buffer is an ordinary Emacs buffer, you can switch to other buffers while in the middle of composing mail, and switch back later (or never). If you use the C-x m command again when you have been composing another message but have not sent it, you are asked to confirm before the old message is erased. If you answer n, the ‘*mail*’ buffer remains selected with its old contents, so you can finish the old message and send it. C-u C-x m is another way to do this. Sending the message marks the ‘*mail*’ buffer “unmodified,” which avoids the need for confirmation when C-x m is next used.
If you are composing a message in the ‘*mail*’ buffer and want to send another message before finishing the first, rename the ‘*mail*’ buffer using M-x rename-uniquely (see Misc Buffer). Then you can use C-x m or its variants described above to make a new ‘*mail*’ buffer. Once you've done that, you can work with each mail buffer independently.
The variable mail-default-directory controls the default
directory for mail buffers, and also says where to put their auto-save
files.
In addition to the text or body, a message has header fields which say who sent it, when, to whom, why, and so on. Some header fields, such as ‘Date’ and ‘Sender’, are created automatically when you send the message. Others, such as the recipient names, must be specified by you in order to send the message properly.
Mail mode provides a few commands to help you edit some header fields, and some are preinitialized in the buffer automatically at times. You can insert and edit header fields using ordinary editing commands.
The line in the buffer that says
--text follows this line--
is a special delimiter that separates the headers you have specified from
the text. Whatever follows this line is the text of the message; the
headers precede it. The delimiter line itself does not appear in the
message actually sent. The text used for the delimiter line is controlled
by the variable mail-header-separator.
Here is an example of what the headers and text in the mail buffer might look like.
To: gnu@gnu.org
CC: lungfish@spam.org, byob@spam.org
Subject: The Emacs Manual
--Text follows this line--
Please ignore this message.
A header field in the mail buffer starts with a field name at the beginning of a line, terminated by a colon. Upper and lower case are equivalent in field names (and in mailing addresses also). After the colon and optional whitespace comes the contents of the field.
You can use any name you like for a header field, but normally people use only standard field names with accepted meanings. Here is a table of fields commonly used in outgoing messages.
To send a blind carbon copy of every outgoing message to yourself, set
the variable mail-self-blind to t. To send a blind carbon
copy of every message to some other address, set the variable
mail-default-headers to "Bcc: address\n".
To put a fixed file name in the ‘FCC’ field each time you start
editing an outgoing message, set the variable
mail-archive-file-name to that file name. Unless you remove the
‘FCC’ field before sending, the message will be written into that
file when it is sent.
user-mail-address as the default.
To put a fixed ‘Reply-to’ address into every outgoing message, set
the variable mail-default-reply-to to that address (as a string).
Then mail initializes the message with a ‘Reply-to’ field as
specified. You can delete or alter that header field before you send
the message, if you wish. When Emacs starts up, if the environment
variable REPLYTO is set, mail-default-reply-to is
initialized from that environment variable.
The ‘To’, ‘CC’, and ‘BCC’ header fields can appear any number of times, and each such header field can contain multiple addresses, separated by commas. This way, you can specify any number of places to send the message. These fields can also have continuation lines: one or more lines starting with whitespace, following the starting line of the field, are considered part of the field. Here's an example of a ‘To’ field with a continuation line:
To: foo@here.net, this@there.net,
me@gnu.cambridge.mass.usa.earth.spiral3281
When you send the message, if you didn't write a ‘From’ field
yourself, Emacs puts in one for you. The variable
mail-from-style controls the format:
nilparensanglessystem-default You can direct Emacs to insert certain default headers into the
outgoing message by setting the variable mail-default-headers
to a string. Then C-x m inserts this string into the message
headers. If the default header fields are not appropriate for a
particular message, edit them as appropriate before sending the
message.
You can define mail aliases in a file named ~/.mailrc. These are short mnemonic names which stand for mail addresses or groups of mail addresses. Like many other mail programs, Emacs expands aliases when they occur in the ‘To’, ‘From’, ‘CC’, ‘BCC’, and ‘Reply-to’ fields, plus their ‘Resent-’ variants.
To define an alias in ~/.mailrc, write a line in the following format:
alias shortaddress fulladdresses
Here fulladdresses stands for one or more mail addresses for shortaddress to expand into. Separate multiple addresses with spaces; if an address contains a space, quote the whole address with a pair of double-quotes.
For instance, to make maingnu stand for
gnu@gnu.org plus a local address of your own, put in
this line:
alias maingnu gnu@gnu.org local-gnu
Addresses specified in this way should use doublequotes around an entire address when the address contains spaces. But you need not include doublequotes around parts of the address, such as the person's full name. Emacs puts them in if they are needed. For example,
alias chief-torturer "George W. Bush <bush@whitehouse.gov>"
is correct. Emacs will insert the address as ‘"George W. Bush" <bush@whitehouse.gov>’.
Emacs also recognizes “include” commands in ‘.mailrc’ files. They look like this:
source filename
The file ~/.mailrc is used primarily by other mail-reading programs; it can contain various other commands. Emacs ignores everything in it except for alias definitions and include commands.
Another way to define a mail alias, within Emacs alone, is with the
define-mail-alias command. It prompts for the alias and then the
full address. You can use it to define aliases in your .emacs
file, like this:
(define-mail-alias "maingnu" "gnu@gnu.org")
define-mail-alias records aliases by adding them to a
variable named mail-aliases. If you are comfortable with
manipulating Lisp lists, you can set mail-aliases directly. The
initial value of mail-aliases is t, which means that
Emacs should read .mailrc to get the proper value.
You can specify a different file name to use instead of
~/.mailrc by setting the variable
mail-personal-alias-file.
Normally, Emacs expands aliases when you send the message. You do not need to expand mail aliases before sending the message, but you can expand them if you want to see where the mail will actually go. To do this, use the command M-x expand-mail-aliases; it expands all mail aliases currently present in the mail headers that hold addresses.
If you like, you can have mail aliases expand as abbrevs, as soon as you type them in (see Abbrevs). To enable this feature, execute the following:
(add-hook 'mail-mode-hook 'mail-abbrevs-setup)
This can go in your .emacs file. See Hooks. If you use this
feature, you must use define-mail-abbrev instead of
define-mail-alias; the latter does not work with this package.
Note that the mail abbreviation package uses the variable
mail-abbrevs instead of mail-aliases, and that all alias
names are converted to lower case.
The mail abbreviation package also provides the C-c C-a
(mail-interactive-insert-alias) command, which reads an alias
name (with completion) and inserts its definition at point. This is
useful when editing the message text itself or a header field such as
‘Subject’ in which Emacs does not normally expand aliases.
Note that abbrevs expand only if you insert a word-separator character afterward. However, you can rebind C-n and M-> to cause expansion as well. Here's how to do that:
(add-hook 'mail-mode-hook
(lambda ()
(define-key
mail-mode-map [remap next-line] 'mail-abbrev-next-line)
(define-key
mail-mode-map [remap end-of-buffer] 'mail-abbrev-end-of-buffer)))
The major mode used in the mail buffer is Mail mode, which is much like Text mode except that various special commands are provided on the C-c prefix. These commands all have to do specifically with editing or sending the message. In addition, Mail mode defines the character ‘%’ as a word separator; this is helpful for using the word commands to edit mail addresses.
Mail mode is normally used in buffers set up automatically by the
mail command and related commands. However, you can also switch
to Mail mode in a file-visiting buffer. This is a useful thing to do if
you have saved the text of a draft message in a file.
Mail mode has two commands for sending the message you have been editing:
mail-send).
mail-send-and-exit).
C-c C-s (mail-send) sends the message and marks the mail
buffer unmodified, but leaves that buffer selected so that you can
modify the message (perhaps with new recipients) and send it again.
C-c C-c (mail-send-and-exit) sends and then deletes the
window or switches to another buffer. It puts the mail buffer at the
lowest priority for reselection by default, since you are finished with
using it. This is the usual way to send the message.
In a file-visiting buffer, sending the message does not clear the modified flag, because only saving the file should do that. As a result, you don't get a warning if you try to send the same message twice.
When you send a message that contains non-ASCII characters, they need
to be encoded with a coding system (see Coding Systems). Usually
the coding system is specified automatically by your chosen language
environment (see Language Environments). You can explicitly specify
the coding system for outgoing mail by setting the variable
sendmail-coding-system (see Recognize Coding).
If the coding system thus determined does not handle the characters in a particular message, Emacs asks you to select the coding system to use, showing a list of possible coding systems.
The variable send-mail-function controls how the default mail
user agent sends mail. It should be set to a function. The default
is sendmail-send-it, which delivers mail using the Sendmail
installation on the local host. To send mail through a SMTP server,
set it to smtpmail-send-it and set up the Emacs SMTP library
(see Sending mail via SMTP). A third option is
feedmail-send-it, see the commentary section of the
feedmail.el package for more information.
Mail mode provides special commands to move to particular header fields and to complete addresses in headers.
mail-to).
mail-subject).
mail-cc).
mail-bcc).
mail-fcc).
mail-complete).
There are five commands to move point to particular header fields, all based on the prefix C-c C-f (‘C-f’ is for “field”). They are listed in the table above. If the field in question does not exist, these commands create one. We provide special motion commands for these particular fields because they are the fields users most often want to edit.
While editing a header field that contains mailing addresses, such
as ‘To:’, ‘CC:’ and ‘BCC:’, you can complete a mailing
address by typing M-<TAB> (mail-complete). It
inserts the full name corresponding to the address, if it can
determine the full name. The variable mail-complete-style
controls whether to insert the full name, and what style to use, as in
mail-from-style (see Mail Headers). (If your window
manager defines M-<TAB> to switch windows, you can type
<ESC> <TAB> or C-M-i.)
For completion purposes, the valid mailing addresses are taken to be the local users' names plus your personal mail aliases. You can specify additional sources of valid addresses; see the customization group ‘mailalias’ to see the variables for customizing this feature (see Customization Groups).
If you type M-<TAB> in the body of the message,
mail-complete invokes ispell-complete-word, as in Text
mode.
Mail mode also has commands for yanking or citing all or part of a message that you are replying to. These commands are active only when you started sending a message using an Rmail command.
mail-yank-original).
mail-yank-region).
mail-fill-yanked-message).
When mail sending is invoked from the Rmail mail reader using an Rmail command, C-c C-y can be used inside the mail buffer to insert the text of the message you are replying to. Normally it indents each line of that message three spaces and eliminates most header fields. A numeric argument specifies the number of spaces to indent. An argument of just C-u says not to indent at all and not to eliminate anything. C-c C-y always uses the current message from the Rmail buffer, so you can insert several old messages by selecting one in Rmail, switching to ‘*mail*’ and yanking it, then switching back to Rmail to select another.
You can specify the text for C-c C-y to insert at the beginning
of each line: set mail-yank-prefix to the desired string. (A
value of nil means to use indentation; this is the default.)
However, C-u C-c C-y never adds anything at the beginning of the
inserted lines, regardless of the value of mail-yank-prefix.
To yank just a part of an incoming message, set the region in Rmail to
the part you want; then go to the ‘*Mail*’ message and type
C-c C-r (mail-yank-region). Each line that is copied is
indented or prefixed according to mail-yank-prefix.
After using C-c C-y or C-c C-r, you can type C-c C-q
(mail-fill-yanked-message) to fill the paragraphs of the yanked
old message or messages. One use of C-c C-q fills all such
paragraphs, each one individually. To fill a single paragraph of the
quoted message, use M-q. If filling does not automatically
handle the type of citation prefix you use, try setting the fill prefix
explicitly. See Filling.
mail-text).
mail-signature).
mail-attach-file).
C-c C-t (mail-text) moves point to just after the header
separator line—that is, to the beginning of the message body text.
C-c C-w (mail-signature) adds a standard piece of text at
the end of the message to say more about who you are. The text comes
from the file ~/.signature in your home directory. To insert
your signature automatically, set the variable mail-signature to
t; after that, starting a mail message automatically inserts the
contents of your ~/.signature file. If you want to omit your
signature from a particular message, delete it from the buffer before
you send the message.
You can also set mail-signature to a string; then that string
is inserted automatically as your signature when you start editing a
message to send. If you set it to some other Lisp expression, the
expression is evaluated each time, and its value (which should be a
string) specifies the signature.
You can do spelling correction on the message text you have written
with the command M-x ispell-message. If you have yanked an
incoming message into the outgoing draft, this command skips what was
yanked, but it checks the text that you yourself inserted. (It looks
for indentation or mail-yank-prefix to distinguish the cited
lines from your input.) See Spelling.
To include a file in the outgoing message, you can use C-x i,
the usual command to insert a file in the current buffer. But it is
often more convenient to use a special command, C-c C-i
(mail-attach-file). This command inserts the file contents at
the end of the buffer, after your signature if any, with a delimiter
line that includes the file name. Note that this is not a MIME
attachment.
Turning on Mail mode (which C-x m does automatically) runs the
normal hooks text-mode-hook and mail-mode-hook.
Initializing a new outgoing message runs the normal hook
mail-setup-hook; if you want to add special fields to your mail
header or make other changes to the appearance of the mail buffer, use
that hook. See Hooks.
The main difference between these hooks is just when they are
invoked. Whenever you type M-x mail, mail-mode-hook runs
as soon as the ‘*mail*’ buffer is created. Then the
mail-setup function inserts the default contents of the buffer.
After these default contents are inserted, mail-setup-hook runs.
M-x spook adds a line of randomly chosen keywords to an outgoing mail message. The keywords are chosen from a list of words that suggest you are discussing something subversive.
The idea behind this feature is the suspicion that the NSA18 snoops on all electronic mail messages that contain keywords suggesting they might find them interesting. (The NSA says they don't, but that's what they would say.) The idea is that if lots of people add suspicious words to their messages, the NSA will get so busy with spurious input that they will have to give up reading it all.
Here's how to insert spook keywords automatically whenever you start entering an outgoing message:
(add-hook 'mail-setup-hook 'spook)
Whether or not this confuses the NSA, it at least amuses people.
You can use the fortune program to put a “fortune cookie”
message into outgoing mail. To do this, add
fortune-to-signature to mail-setup-hook:
(add-hook 'mail-setup-hook 'fortune-to-signature)
In this chapter we have described the usual Emacs mode for editing
and sending mail—Mail mode. Emacs has alternative facilities for
editing and sending mail, including
MH-E and Message mode, not documented in this manual.
See MH-E. See Message. You can choose any of them as your preferred method.
The commands C-x m, C-x 4 m and C-x 5 m use
whichever agent you have specified, as do various other Emacs commands
and facilities that send mail.
To specify your mail-composition method, customize the variable
mail-user-agent. Currently legitimate values include
sendmail-user-agent (Mail mode), mh-e-user-agent,
message-user-agent and gnus-user-agent.
If you select a different mail-composition method, the information in this chapter about the ‘*mail*’ buffer and Mail mode does not apply; the other methods use a different format of text in a different buffer, and their commands are different as well.
Rmail is an Emacs subsystem for reading and disposing of mail that you
receive. Rmail stores mail messages in files called Rmail files.
Reading the message in an Rmail file is done in a special major mode,
Rmail mode, which redefines most letters to run commands for managing
mail. The command rmail-mode is used to switch into Rmail mode,
and it runs the hook rmail-mode-hook as usual, but don't run this
command by hand; it can't do a reasonable job unless the buffer is
visiting a proper Rmail file.
Using Rmail in the simplest fashion, you have one Rmail file
~/RMAIL in which all of your mail is saved. It is called your
primary Rmail file. The command M-x rmail reads your primary
Rmail file, merges new mail in from your inboxes, displays the first
message you haven't read yet, and lets you begin reading. The variable
rmail-file-name specifies the name of the primary Rmail file.
Rmail uses narrowing to hide all but one message in the Rmail file. The message that is shown is called the current message. Rmail mode's special commands can do such things as delete the current message, copy it into another file, send a reply, or move to another message. You can also create multiple Rmail files and use Rmail to move messages between them.
Within the Rmail file, messages are normally arranged sequentially in order of receipt; you can specify other ways to sort them. Messages are assigned consecutive integers as their message numbers. The number of the current message is displayed in Rmail's mode line, followed by the total number of messages in the file. You can move to a message by specifying its message number with the j key (see Rmail Motion).
Following the usual conventions of Emacs, changes in an Rmail file
become permanent only when the file is saved. You can save it with
s (rmail-expunge-and-save), which also expunges deleted
messages from the file first (see Rmail Deletion). To save the
file without expunging, use C-x C-s. Rmail also saves the Rmail
file after merging new mail from an inbox file (see Rmail Inbox).
You can exit Rmail with q (rmail-quit); this expunges
and saves the Rmail file, then buries the Rmail buffer as well as its
summary buffer, if present (see Rmail Summary). But there is no
need to “exit” formally. If you switch from Rmail to editing in
other buffers, and never happen to switch back, you have exited. Just
make sure to save the Rmail file eventually (like any other file you
have changed). C-x s is a good enough way to do this
(see Save Commands). The Rmail command b, rmail-bury,
buries the Rmail buffer and its summary buffer without expunging and
saving the Rmail file.
When Rmail displays a message that does not fit on the screen, you must scroll through it to read the rest. You could do this with C-v, M-v and M-<, but in Rmail scrolling is so frequent that it deserves to be easier to type.
scroll-up).
scroll-down).
rmail-beginning-of-message).
Since the most common thing to do while reading a message is to scroll
through it by screenfuls, Rmail makes <SPC> and <DEL> synonyms of
C-v (scroll-up) and M-v (scroll-down)
The command . (rmail-beginning-of-message) scrolls back to the
beginning of the selected message. This is not quite the same as M-<:
for one thing, it does not set the mark; for another, it resets the buffer
boundaries to the current message if you have changed them.
The most basic thing to do with a message is to read it. The way to do this in Rmail is to make the message current. The usual practice is to move sequentially through the file, since this is the order of receipt of messages. When you enter Rmail, you are positioned at the first message that you have not yet made current (that is, the first one that has the ‘unseen’ attribute; see Rmail Attributes). Move forward to see the other new messages; move backward to re-examine old messages.
rmail-next-undeleted-message).
rmail-previous-undeleted-message).
rmail-next-message).
rmail-previous-message).
rmail-show-message).
rmail-last-message).
rmail-first-message).
rmail-search).
n and p are the usual way of moving among messages in
Rmail. They move through the messages sequentially, but skip over
deleted messages, which is usually what you want to do. Their command
definitions are named rmail-next-undeleted-message and
rmail-previous-undeleted-message. If you do not want to skip
deleted messages—for example, if you want to move to a message to
undelete it—use the variants M-n and M-p
(rmail-next-message and rmail-previous-message). A
numeric argument to any of these commands serves as a repeat
count.
In Rmail, you can specify a numeric argument by typing just the digits. You don't need to type C-u first.
The M-s (rmail-search) command is Rmail's version of
search. The usual incremental search command C-s works in Rmail,
but it searches only within the current message. The purpose of
M-s is to search for another message. It reads a regular
expression (see Regexps) nonincrementally, then searches starting at
the beginning of the following message for a match. It then selects
that message. If regexp is empty, M-s reuses the regexp
used the previous time.
To search backward in the file for another message, give M-s a negative argument. In Rmail you can do this with - M-s.
It is also possible to search for a message based on labels. See Rmail Labels.
To move to a message specified by absolute message number, use j
(rmail-show-message) with the message number as argument. With
no argument, j selects the first message. <
(rmail-first-message) also selects the first message. >
(rmail-last-message) selects the last message.
When you no longer need to keep a message, you can delete it. This flags it as ignorable, and some Rmail commands pretend it is no longer present; but it still has its place in the Rmail file, and still has its message number.
Expunging the Rmail file actually removes the deleted messages. The remaining messages are renumbered consecutively. Expunging is the only action that changes the message number of any message, except for undigestifying (see Rmail Digest).
rmail-delete-forward).
rmail-delete-backward).
rmail-undelete-previous-message).
rmail-expunge).
There are two Rmail commands for deleting messages. Both delete the
current message and select another message. d
(rmail-delete-forward) moves to the following message, skipping
messages already deleted, while C-d (rmail-delete-backward)
moves to the previous nondeleted message. If there is no nondeleted
message to move to in the specified direction, the message that was just
deleted remains current. d with a numeric argument is
equivalent to C-d.
Whenever Rmail deletes a message, it runs the hook
rmail-delete-message-hook. When the hook functions are invoked,
the message has been marked deleted, but it is still the current message
in the Rmail buffer.
To make all the deleted messages finally vanish from the Rmail file,
type x (rmail-expunge). Until you do this, you can still
undelete the deleted messages. The undeletion command, u
(rmail-undelete-previous-message), is designed to cancel the
effect of a d command in most cases. It undeletes the current
message if the current message is deleted. Otherwise it moves backward
to previous messages until a deleted message is found, and undeletes
that message.
You can usually undo a d with a u because the u moves back to and undeletes the message that the d deleted. But this does not work when the d skips a few already-deleted messages that follow the message being deleted; then the u command undeletes the last of the messages that were skipped. There is no clean way to avoid this problem. However, by repeating the u command, you can eventually get back to the message that you intend to undelete. You can also select a particular deleted message with the M-p command, then type u to undelete it.
A deleted message has the ‘deleted’ attribute, and as a result ‘deleted’ appears in the mode line when the current message is deleted. In fact, deleting or undeleting a message is nothing more than adding or removing this attribute. See Rmail Attributes.
When you receive mail locally, the operating system places incoming
mail for you in a file that we call your inbox. When you start
up Rmail, it runs a C program called movemail to copy the new
messages from your local inbox into your primary Rmail file, which
also contains other messages saved from previous Rmail sessions. It
is in this file that you actually read the mail with Rmail. This
operation is called getting new mail. You can get new mail at
any time in Rmail by typing g.
The variable rmail-primary-inbox-list contains a list of the
files which are inboxes for your primary Rmail file. If you don't set
this variable explicitly, it is initialized from the MAIL
environment variable, or, as a last resort, set to nil, which
means to use the default inbox. The default inbox is
/var/mail/username, /usr/spool/mail/username,
or /usr/mail/username, depending on your operating system.
To see what the default is on your system, use C-h v
rmail-primary-inbox-list <RET>. You can specify the inbox file(s) for
any Rmail file with the command set-rmail-inbox-list; see
Rmail Files.
There are two reasons for having separate Rmail files and inboxes.
Rmail was written to use Babyl format as its internal format. Since then, we have recognized that the usual inbox format on Unix and GNU systems is adequate for the job, and we plan to change Rmail to use that as its internal format. However, the Rmail file will still be separate from the inbox file, even on systems where their format is the same.
When getting new mail, Rmail first copies the new mail from the inbox
file to the Rmail file; then it saves the Rmail file; then it truncates
the inbox file. This way, a system crash may cause duplication of mail
between the inbox and the Rmail file, but cannot lose mail. If
rmail-preserve-inbox is non-nil, then Rmail will copy new
mail from the inbox file to the Rmail file without truncating the inbox
file. You may wish to set this, for example, on a portable computer you
use to check your mail via POP while traveling, so that your mail will
remain on the server and you can save it later on your workstation.
In some cases, Rmail copies the new mail from the inbox file
indirectly. First it runs the movemail program to move the mail
from the inbox to an intermediate file called
~/.newmail-inboxname. Then Rmail merges the new mail from
that file, saves the Rmail file, and only then deletes the intermediate
file. If there is a crash at the wrong time, this file continues to
exist, and Rmail will use it again the next time it gets new mail from
that inbox.
If Rmail is unable to convert the data in ~/.newmail-inboxname into Babyl format, it renames the file to ~/RMAILOSE.n (n is an integer chosen to make the name unique) so that Rmail will not have trouble with the data again. You should look at the file, find whatever message confuses Rmail (probably one that includes the control-underscore character, octal code 037), and delete it. Then you can use 1 g to get new mail from the corrected file.
Rmail operates by default on your primary Rmail file, which is named ~/RMAIL and receives your incoming mail from your system inbox file. But you can also have other Rmail files and edit them with Rmail. These files can receive mail through their own inboxes, or you can move messages into them with explicit Rmail commands (see Rmail Output).
rmail-input).
rmail-get-new-mail).
To run Rmail on a file other than your primary Rmail file, you may use
the i (rmail-input) command in Rmail. This visits the file
in Rmail mode. You can use M-x rmail-input even when not in
Rmail.
The file you read with i should normally be a valid Rmail file. If it is not, Rmail tries to decompose it into a stream of messages in various known formats. If it succeeds, it converts the whole file to an Rmail file. If you specify a file name that doesn't exist, i initializes a new buffer for creating a new Rmail file.
You can also select an Rmail file from a menu. Choose first the menu
bar Classify item, then from the Classify menu choose the Input Rmail
File item; then choose the Rmail file you want. The variables
rmail-secondary-file-directory and
rmail-secondary-file-regexp specify which files to offer in the
menu: the first variable says which directory to find them in; the
second says which files in that directory to offer (all those that match
the regular expression). These variables also apply to choosing a file
for output (see Rmail Output).
Each Rmail file can contain a list of inbox file names; you can specify this list with M-x set-rmail-inbox-list <RET> files <RET>. The argument can contain any number of file names, separated by commas. It can also be empty, which specifies that this file should have no inboxes. Once a list of inboxes is specified, the Rmail file remembers it permanently until you specify a different list.
As a special exception, if your primary Rmail file does not specify any inbox files, it uses your standard system inbox.
The g command (rmail-get-new-mail) merges mail into the
current Rmail file from its specified inboxes. If the Rmail file
has no inboxes, g does nothing. The command M-x rmail
also merges new mail into your primary Rmail file.
To merge mail from a file that is not the usual inbox, give the g key a numeric argument, as in C-u g. Then it reads a file name and merges mail from that file. The inbox file is not deleted or changed in any way when g with an argument is used. This is, therefore, a general way of merging one file of messages into another.
These commands copy messages from an Rmail file into another file.
rmail-output-to-rmail-file).
rmail-output).
The commands o and C-o copy the current message into a specified file. This file may be an Rmail file or it may be in system inbox format; the output commands ascertain the file's format and write the copied message in that format.
The o and C-o commands differ in two ways: each has its own separate default file name, and each specifies a choice of format to use when the file does not already exist. The o command uses Rmail format when it creates a new file, while C-o uses system inbox format for a new file. The default file name for o is the file name used last with o, and the default file name for C-o is the file name used last with C-o.
If the output file is an Rmail file currently visited in an Emacs buffer, the output commands copy the message into that buffer. It is up to you to save the buffer eventually in its file.
Sometimes you may receive a message whose body holds the contents of a
file. You can save the body to a file (excluding the message header)
with the w command (rmail-output-body-to-file). Often
these messages contain the intended file name in the ‘Subject’
field, so the w command uses the ‘Subject’ field as the
default for the output file name. However, the file name is read using
the minibuffer, so you can specify a different name if you wish.
You can also output a message to an Rmail file chosen with a menu.
Choose first the menu bar Classify item, then from the Classify menu
choose the Output Rmail File menu item; then choose the Rmail file you want.
This outputs the current message to that file, like the o command.
The variables rmail-secondary-file-directory and
rmail-secondary-file-regexp specify which files to offer in the
menu: the first variable says which directory to find them in; the
second says which files in that directory to offer (all those that match
the regular expression).
Copying a message with o or C-o gives the original copy
of the message the ‘filed’ attribute, so that ‘filed’
appears in the mode line when such a message is current. w
gives it the ‘stored’ attribute. If you like to keep just a
single copy of every mail message, set the variable
rmail-delete-after-output to t; then the o,
C-o and w commands delete the original message after
copying it. (You can undelete the original afterward if you wish.)
Copying messages into files in system inbox format uses the header fields that are displayed in Rmail at the time. Thus, if you use the t command to view the entire header and then copy the message, the entire header is copied. See Rmail Display.
The variable rmail-output-file-alist lets you specify
intelligent defaults for the output file, based on the contents of the
current message. The value should be a list whose elements have this
form:
(regexp . name-exp)
If there's a match for regexp in the current message, then the
default file name for output is name-exp. If multiple elements
match the message, the first matching element decides the default file
name. The subexpression name-exp may be a string constant giving
the file name to use, or more generally it may be any Lisp expression
that returns a file name as a string. rmail-output-file-alist
applies to both o and C-o.
Each message can have various labels assigned to it as a means of classification. Each label has a name; different names are different labels. Any given label is either present or absent on a particular message. A few label names have standard meanings and are given to messages automatically by Rmail when appropriate; these special labels are called attributes. All other labels are assigned only by users.
rmail-add-label).
rmail-kill-label).
rmail-next-labeled-message).
rmail-previous-labeled-message).
rmail-summary-by-labels).
The a (rmail-add-label) and k
(rmail-kill-label) commands allow you to assign or remove any
label on the current message. If the label argument is empty, it
means to assign or remove the same label most recently assigned or
removed.
Once you have given messages labels to classify them as you wish, there are two ways to use the labels: in moving and in summaries.
The command C-M-n labels <RET>
(rmail-next-labeled-message) moves to the next message that has
one of the labels labels. The argument labels specifies one
or more label names, separated by commas. C-M-p
(rmail-previous-labeled-message) is similar, but moves backwards
to previous messages. A numeric argument to either command serves as a
repeat count.
The command C-M-l labels <RET>
(rmail-summary-by-labels) displays a summary containing only the
messages that have at least one of a specified set of labels. The
argument labels is one or more label names, separated by commas.
See Rmail Summary, for information on summaries.
If the labels argument to C-M-n, C-M-p or C-M-l is empty, it means to use the last set of labels specified for any of these commands.
Some labels such as ‘deleted’ and ‘filed’ have built-in meanings and are assigned to or removed from messages automatically at appropriate times; these labels are called attributes. Here is a list of Rmail attributes:
rmail-reply). See Rmail Reply.
rmail-forward). See Rmail Reply.
All other labels are assigned or removed only by the user, and have no standard meaning.
Rmail has several commands that use Mail mode to send outgoing mail. See Sending Mail, for information on using Mail mode, including certain features meant to work with Rmail. What this section documents are the special commands of Rmail for entering Mail mode. Note that the usual keys for sending mail—C-x m, C-x 4 m, and C-x 5 m—are available in Rmail mode and work just as they usually do.
rmail-mail).
rmail-continue).
rmail-reply).
rmail-forward).
rmail-resend).
rmail-retry-failure).
The most common reason to send a message while in Rmail is to reply to
the message you are reading. To do this, type r
(rmail-reply). This displays the ‘*mail*’ buffer in another
window, much like C-x 4 m, but preinitializes the ‘Subject’,
‘To’, ‘CC’ and ‘In-reply-to’ header fields based on the
message you are replying to. The ‘To’ field starts out as the
address of the person who sent the message you received, and the
‘CC’ field starts out with all the other recipients of that
message.
You can exclude certain recipients from being placed automatically in
the ‘CC’, using the variable rmail-dont-reply-to-names. Its
value should be a regular expression (as a string); any recipient that
the regular expression matches, is excluded from the ‘CC’ field.
The default value matches your own name, and any name starting with
‘info-’. (Those names are excluded because there is a convention
of using them for large mailing lists to broadcast announcements.)
To omit the ‘CC’ field completely for a particular reply, enter the reply command with a numeric argument: C-u r or 1 r.
Once the ‘*mail*’ buffer has been initialized, editing and sending the mail goes as usual (see Sending Mail). You can edit the presupplied header fields if they are not right for you. You can also use the commands of Mail mode (see Mail Mode), including C-c C-y which yanks in the message that you are replying to. You can switch to the Rmail buffer, select a different message there, switch back, and yank the new current message.
Sometimes a message does not reach its destination. Mailers usually
send the failed message back to you, enclosed in a failure
message. The Rmail command M-m (rmail-retry-failure)
prepares to send the same message a second time: it sets up a
‘*mail*’ buffer with the same text and header fields as before. If
you type C-c C-c right away, you send the message again exactly
the same as the first time. Alternatively, you can edit the text or
headers and then send it. The variable
rmail-retry-ignored-headers, in the same format as
rmail-ignored-headers (see Rmail Display), controls which
headers are stripped from the failed message when retrying it.
Another frequent reason to send mail in Rmail is to forward the
current message to other users. f (rmail-forward) makes
this easy by preinitializing the ‘*mail*’ buffer with the current
message as the text, and a subject designating a forwarded message. All
you have to do is fill in the recipients and send. When you forward a
message, recipients get a message which is “from” you, and which has
the original message in its contents.
Forwarding a message encloses it between two delimiter lines. It also modifies every line that starts with a dash, by inserting ‘- ’ at the start of the line. When you receive a forwarded message, if it contains something besides ordinary text—for example, program source code—you might find it useful to undo that transformation. You can do this by selecting the forwarded message and typing M-x unforward-rmail-message. This command extracts the original forwarded message, deleting the inserted ‘- ’ strings, and inserts it into the Rmail file as a separate message immediately following the current one.
Resending is an alternative similar to forwarding; the
difference is that resending sends a message that is “from” the
original sender, just as it reached you—with a few added header fields
‘Resent-From’ and ‘Resent-To’ to indicate that it came via
you. To resend a message in Rmail, use C-u f. (f runs
rmail-forward, which is programmed to invoke rmail-resend
if you provide a numeric argument.)
The m (rmail-mail) command is used to start editing an
outgoing message that is not a reply. It leaves the header fields empty.
Its only difference from C-x 4 m is that it makes the Rmail buffer
accessible for C-c C-y, just as r does. Thus, m can be
used to reply to or forward a message; it can do anything r or f
can do.
The c (rmail-continue) command resumes editing the
‘*mail*’ buffer, to finish editing an outgoing message you were
already composing, or to alter a message you have sent.
If you set the variable rmail-mail-new-frame to a
non-nil value, then all the Rmail commands to start sending a
message create a new frame to edit it in. This frame is deleted when
you send the message, or when you use the ‘Cancel’ item in the
‘Mail’ menu.
All the Rmail commands to send a message use the mail-composition method that you have chosen (see Mail Methods).
A summary is a buffer containing one line per message to give you an overview of the mail in an Rmail file. Each line shows the message number and date, the sender, the line count, the labels, and the subject. Moving point in the summary buffer selects messages as you move to their summary lines. Almost all Rmail commands are valid in the summary buffer also; when used there, they apply to the message described by the current line of the summary.
A summary buffer applies to a single Rmail file only; if you are editing multiple Rmail files, each one can have its own summary buffer. The summary buffer name is made by appending ‘-summary’ to the Rmail buffer's name. Normally only one summary buffer is displayed at a time.
Here are the commands to create a summary for the current Rmail file. Once the Rmail file has a summary buffer, changes in the Rmail file (such as deleting or expunging messages, and getting new mail) automatically update the summary.
rmail-summary).
rmail-summary-by-labels).
rmail-summary-by-recipients).
rmail-summary-by-topic).
rmail-summary-by-regexp).
The h or C-M-h (rmail-summary) command fills the summary buffer
for the current Rmail file with a summary of all the messages in the file.
It then displays and selects the summary buffer in another window.
C-M-l labels <RET> (rmail-summary-by-labels) makes
a partial summary mentioning only the messages that have one or more of the
labels labels. labels should contain label names separated by
commas.
C-M-r rcpts <RET> (rmail-summary-by-recipients)
makes a partial summary mentioning only the messages that have one or more
of the recipients rcpts. rcpts should contain mailing
addresses separated by commas.
C-M-t topic <RET> (rmail-summary-by-topic)
makes a partial summary mentioning only the messages whose subjects have
a match for the regular expression topic.
C-M-s regexp <RET> (rmail-summary-by-regexp)
makes a partial summary which mentions only the messages whose headers
(including the date and the subject lines) match the regular
expression regexp.
Note that there is only one summary buffer for any Rmail file; making one kind of summary discards any previously made summary.
The variable rmail-summary-window-size says how many lines to
use for the summary window. The variable
rmail-summary-line-count-flag controls whether the summary line
for a message should include the line count of the message.
You can use the Rmail summary buffer to do almost anything you can do in the Rmail buffer itself. In fact, once you have a summary buffer, there's no need to switch back to the Rmail buffer.
You can select and display various messages in the Rmail buffer, from the summary buffer, just by moving point in the summary buffer to different lines. It doesn't matter what Emacs command you use to move point; whichever line point is on at the end of the command, that message is selected in the Rmail buffer.
Almost all Rmail commands work in the summary buffer as well as in the Rmail buffer. Thus, d in the summary buffer deletes the current message, u undeletes, and x expunges. (However, in the summary buffer, a numeric argument to d, C-d and u serves as a repeat count. A negative argument reverses the meaning of d and C-d.) o and C-o output the current message to a file; r starts a reply to it. You can scroll the current message while remaining in the summary buffer using <SPC> and <DEL>.
The Rmail commands to move between messages also work in the summary buffer, but with a twist: they move through the set of messages included in the summary. They also ensure the Rmail buffer appears on the screen (unlike cursor motion commands, which update the contents of the Rmail buffer but don't display it in a window unless it already appears). Here is a list of these commands:
Deletion, undeletion, and getting new mail, and even selection of a
different message all update the summary buffer when you do them in the
Rmail buffer. If the variable rmail-redisplay-summary is
non-nil, these actions also bring the summary buffer back onto
the screen.
When you are finished using the summary, type Q
(rmail-summary-wipe) to delete the summary buffer's window. You
can also exit Rmail while in the summary: q
(rmail-summary-quit) deletes the summary window, then exits from
Rmail by saving the Rmail file and switching to another buffer.
The Rmail sort commands perform a stable sort: if there is no
reason to prefer either one of two messages, their order remains
unchanged. You can use this to sort by more than one criterion. For
example, if you use rmail-sort-by-date and then
rmail-sort-by-author, messages from the same author appear in
order by date.
With a numeric argument, all these commands reverse the order of comparison. This means they sort messages from newest to oldest, from biggest to smallest, or in reverse alphabetical order.
Rmail reformats the header of each message before displaying it for the first time. Reformatting hides uninteresting header fields to reduce clutter. You can use the t command to show the entire header or to repeat the header reformatting operation.
rmail-toggle-header).
Reformatting the header involves deleting most header fields, on the
grounds that they are not interesting. The variable
rmail-ignored-headers holds a regular expression that specifies
which header fields to hide in this way—if it matches the beginning of
a header field, that whole field is hidden.
Rmail saves the complete original header before reformatting; to see
it, use the t command (rmail-toggle-header). This
discards the reformatted headers of the current message and displays it
with the original header. Repeating t reformats the message
again. Selecting the message again also reformats.
One consequence of this is that if you edit the reformatted header (using e; see Rmail Editing), subsequent use of t will discard your edits. On the other hand, if you use e after t, to edit the original (unreformatted) header, those changes are permanent.
When the t command has a prefix argument, a positive argument means to show the reformatted header, and a zero or negative argument means to show the full header.
When the terminal supports multiple fonts or colors, Rmail
highlights certain header fields that are especially interesting—by
default, the ‘From’ and ‘Subject’ fields. The variable
rmail-highlighted-headers holds a regular expression that
specifies the header fields to highlight; if it matches the beginning
of a header field, that whole field is highlighted.
If you specify unusual colors for your text foreground and
background, the colors used for highlighting may not go well with
them. If so, specify different colors for the face
rmail-highlight-face. See Faces, for how to do this. To
turn off highlighting entirely in Rmail, set
rmail-highlighted-headers to nil.
You can highlight and activate URLs in incoming messages by adding
the function goto-address to the hook
rmail-show-message-hook. Then you can browse these URLs by
clicking on them with Mouse-2 (or Mouse-1 quickly) or by
moving to one and typing C-c <RET>. See Activating URLs.
Rmail automatically decodes messages which contain non-ASCII characters, just as Emacs does with files you visit and with subprocess output. Rmail uses the standard ‘charset=charset’ header in the message, if any, to determine how the message was encoded by the sender. It maps charset into the corresponding Emacs coding system (see Coding Systems), and uses that coding system to decode message text. If the message header doesn't have the ‘charset’ specification, or if charset is not recognized, Rmail chooses the coding system with the usual Emacs heuristics and defaults (see Recognize Coding).
Occasionally, a message is decoded incorrectly, either because Emacs
guessed the wrong coding system in the absence of the ‘charset’
specification, or because the specification was inaccurate. For
example, a misconfigured mailer could send a message with a
‘charset=iso-8859-1’ header when the message is actually encoded
in koi8-r. When you see the message text garbled, or some of
its characters displayed as empty boxes, this may have happened.
You can correct the problem by decoding the message again using the right coding system, if you can figure out or guess which one is right. To do this, invoke the M-x rmail-redecode-body command. It reads the name of a coding system, encodes the message body using whichever coding system was used to decode it before, then redecodes it using the coding system you specified. If you specified the right coding system, the result should be readable.
Decoding and encoding using the wrong coding system is lossless for most encodings, in particular with 8-bit encodings such as iso-8859 or koi8. So, if the initial attempt to redecode the message didn't result in a legible text, you can try other coding systems until you succeed.
With some coding systems, notably those from the iso-2022 family,
information can be lost in decoding, so that encoding the message
again won't bring back the original incoming text. In such a case,
rmail-redecode-body cannot work. However, the problems that
call for use of rmail-redecode-body rarely occur with those
coding systems. So in practice the command works when you need it.
Most of the usual Emacs commands are available in Rmail mode, though a few, such as C-M-n and C-M-h, are redefined by Rmail for other purposes. However, the Rmail buffer is normally read only, and most of the letters are redefined as Rmail commands. If you want to edit the text of a message, you must use the Rmail command e.
The e command (rmail-edit-current-message) switches from
Rmail mode into Rmail Edit mode, another major mode which is nearly the
same as Text mode. The mode line indicates this change.
In Rmail Edit mode, letters insert themselves as usual and the Rmail commands are not available. When you are finished editing the message and are ready to go back to Rmail, type C-c C-c, which switches back to Rmail mode. Alternatively, you can return to Rmail mode but cancel all the editing that you have done, by typing C-c C-].
Entering Rmail Edit mode runs the hook text-mode-hook; then it
runs the hook rmail-edit-mode-hook (see Hooks). It adds the
attribute ‘edited’ to the message. It also displays the full
headers of the message, so that you can edit the headers as well as the
body of the message, and your changes in the headers will be
permanent.
A digest message is a message which exists to contain and carry several other messages. Digests are used on some moderated mailing lists; all the messages that arrive for the list during a period of time such as one day are put inside a single digest which is then sent to the subscribers. Transmitting the single digest uses much less computer time than transmitting the individual messages even though the total size is the same, because the per-message overhead in network mail transmission is considerable.
When you receive a digest message, the most convenient way to read it is to undigestify it: to turn it back into many individual messages. Then you can read and delete the individual messages as it suits you. To do this, select the digest message and type the command M-x undigestify-rmail-message. This extracts the submessages as separate Rmail messages, and inserts them following the digest. The digest message itself is flagged as deleted.
The command M-x unrmail converts a file in Rmail format to inbox format (also known as the system mailbox, or mbox, format), so that you can use it with other mail-editing tools. You must specify two arguments, the name of the Rmail file and the name to use for the converted file. M-x unrmail does not alter the Rmail file itself.
M-x unrmail is useful if you can run Emacs on the machine where the Rmail file resides, or can access the Rmail file remotely (see Remote Files) from a machine where Emacs is installed. If accessing Rmail files from Emacs is impossible, you can use the b2m program instead. b2m is part of the Emacs distribution, it is installed into the same directory where all the other auxiliary programs (etags etc.) are installed, and its source is available in the Emacs source distribution, so that you could copy the source to the target machine and compile it there.
To convert a file babyl-file into mbox-file, invoke b2m like this:
b2m < babyl-file > mbox-file
Mailing list messages that might offend some readers are sometimes encoded in a simple code called rot13—so named because it rotates the alphabet by 13 letters. This code is not for secrecy, as it provides none; rather, it enables those who might be offended to avoid ever seeing the real text of the message.
To view a buffer using the rot13 code, use the command M-x rot13-other-window. This displays the current buffer in another window which applies the code when displaying the text.
movemail program
When invoked for the first time, Rmail attempts to locate the
movemail program and determine its version. There are two
versions of movemail program: the native one, shipped with GNU
Emacs (the “emacs version”) and the one included in GNU mailutils
(the “mailutils version,” see movemail). They support the same command line syntax and the same
basic subset of options. However, the ‘mailutils’ version offers
additional features.
The Emacs version of movemail is able to retrieve mail from
usual UNIX mailbox formats and from remote mailboxes using the POP3
protocol.
The Mailutils version is able to handle a wide set of mailbox
formats, such as plain UNIX mailboxes, maildir and MH
mailboxes, etc. It is able to retrieve remote mail using POP3 or
IMAP4 protocol, and can retrieve mail from them using a TLS encrypted
channel. It also accepts mailbox argument in the URL form.
The detailed description of mailbox URLs can be found in
URL. In short, a URL
is:
proto://[user[:password]@]host-or-file-name
where square brackets denote optional elements.
Proto can be one of:
mbox://var/spool/mail/smith.
mh://Mail/inbox.
maildir mailbox, e.g., maildir://mail/inbox.
movemail.
pop://smith:guessme@remote.server.net.
imap://smith:guessme@remote.server.net.
Alternatively, you can specify the file name of the mailbox to use. This is equivalent to specifying the ‘file’ protocol:
/var/spool/mail/user == file://var/spool/mail/user
The variable rmail-movemail-program controls which version of
movemail to use. If that is a string, it specifies the
absolute file name of the movemail executable. If it is
nil, Rmail searches for movemail in the directories
listed in rmail-movemail-search-path and exec-path, then
in exec-directory.
Some sites use a method called POP for accessing users' inbox data
instead of storing the data in inbox files. The Emacs
movemail can work with POP if you compile it with the macro
MAIL_USE_POP defined. (You can achieve that by specifying
‘--with-pop’ when you run configure during the
installation of Emacs.)
The Mailutils movemail by default supports POP, unless configured
with ‘--disable-pop’ option.
Both versions of movemail only work with POP3, not with older
versions of POP.
No matter which flavor of movemail you use, you can specify
POP inbox by using POP URL (see Movemail). A POP
URL is a “file name” of the form
‘pop://username@hostname’, where
hostname is the host name or IP address of the remote mail
server and username is the user name on that server.
Additionally, you may specify the password in the mailbox URL:
‘pop://username:password@hostname’. In this
case, password takes preference over the one set by
rmail-remote-password. This is especially useful if you have
several remote mailboxes with different passwords.
For backward compatibility Rmail also supports two alternative ways
of specifying remote POP mailboxes. Specifying inbox name in the form
‘po:username:hostname’ is equivalent to
‘pop://username@hostname’. Alternatively, you may set
a “file name” of ‘po:username’ in the inbox list of an
Rmail file. Movemail will handle such a name by opening a
connection to the POP server. The MAILHOST environment variable
will in this case specify the machine to look for the server on.
Another method for accessing remote mailboxes is IMAP. This method is
supported only by the mailutils movemail. To specify an IMAP
mailbox in the inbox list, use the following mailbox URL:
‘imap://username[:password]@hostname’. The
password part is optional, as described above.
Accessing a remote mailbox may require a password. Rmail uses the following algorithm to retrieve it:
rmail-remote-password is non-nil, its
value is used.
rmail-remote-password-required is non-nil,
then Rmail will ask you for the password to use.
For compatibility with previous versions, rmail-pop-password
and rmail-pop-password-required may be used instead of
rmail-remote-password and rmail-remote-password-required.
If you need to pass additional command-line flags to movemail,
set the variable rmail-movemail-flags a list of the flags you
wish to use. Do not use this variable to pass the ‘-p’ flag to
preserve your inbox contents; use rmail-preserve-inbox instead.
The movemail program installed at your site may support
Kerberos authentication. If it is
supported, it is used by default whenever you attempt to retrieve
POP mail when rmail-pop-password and
rmail-pop-password-required are unset.
Some POP servers store messages in reverse order. If your server does
this, and you would rather read your mail in the order in which it was
received, you can tell movemail to reverse the order of
downloaded messages by adding the ‘-r’ flag to
rmail-movemail-flags.
Mailutils movemail supports TLS encryption. If you wish to
use it, add the ‘--tls’ flag to rmail-movemail-flags.
If your incoming mail is stored on a local machine in a format other
than UNIX mailbox, you will need the mailutils movemail to retrieve
it. See Movemail, for the detailed description of movemail
versions.
For example, to retrieve mail from a maildir inbox located in
/var/spool/mail/in, you would set the following in Rmail inbox list:
maildir://var/spool/mail/in
Dired makes an Emacs buffer containing a listing of a directory, and optionally some of its subdirectories as well. You can use the normal Emacs commands to move around in this buffer, and special Dired commands to operate on the files listed.
The Dired buffer is “read-only,” and inserting text in it is not useful, so ordinary printing characters such as d and x are used for special Dired commands. Some Dired commands mark or flag the current file (that is, the file on the current line); other commands operate on the marked files or on the flagged files.
The Dired-X package provides various extra features for Dired mode. See Dired-X.
To invoke Dired, do C-x d or M-x dired. The command
reads a directory name or wildcard file name pattern as a minibuffer
argument to specify which files to list. C-x C-f given a
directory name also invokes Dired. Where dired differs from
list-directory is that it puts the buffer into Dired mode, so
that the special commands of Dired are available.
The variable dired-listing-switches specifies the options to
give to ls for listing the directory; this string must contain
‘-l’. If you use a numeric prefix argument with the dired
command, you can specify the ls switches with the minibuffer
before you enter the directory specification. No matter how they are
specified, the ls switches should all be short options (that
is, single characters) requiring no arguments.
To display the Dired buffer in another window rather than in the
selected window, use C-x 4 d (dired-other-window) instead
of C-x d. C-x 5 d (dired-other-frame) uses a
separate frame to display the Dired buffer.
All the usual Emacs cursor motion commands are available in Dired buffers. Some special-purpose cursor motion commands are also provided. The keys C-n and C-p are redefined to put the cursor at the beginning of the file name on the line, rather than at the beginning of the line.
For extra convenience, <SPC> and n in Dired are equivalent to C-n. p is equivalent to C-p. (Moving by lines is so common in Dired that it deserves to be easy to type.) <DEL> (move up and unflag) is often useful simply for moving up.
M-g (dired-goto-file) moves point to the line that
describes a specified file or directory.
Some additional navigation commands are available when the Dired buffer includes several directories. See Subdirectory Motion.
One of the most frequent uses of Dired is to first flag files for deletion, then delete the files that were flagged.
You can flag a file for deletion by moving to the line describing the
file and typing d (dired-flag-file-deletion). The deletion flag is visible as a ‘D’ at
the beginning of the line. This command moves point to the next line,
so that repeated d commands flag successive files. A numeric
argument serves as a repeat count.
The variable dired-recursive-deletes controls whether the
delete command will delete non-empty directories (including their
contents). The default is to delete only empty directories.
The files are flagged for deletion rather than deleted immediately to
reduce the danger of deleting a file accidentally. Until you direct
Dired to delete the flagged files, you can remove deletion flags using
the commands u and <DEL>. u (dired-unmark) works
just like d, but removes flags rather than making flags.
<DEL> (dired-unmark-backward) moves upward, removing flags;
it is like u with argument −1.
To delete the flagged files, type x (dired-do-flagged-delete).
(This is also known as expunging.)
This command first displays a list of all the file names flagged for
deletion, and requests confirmation with yes. If you confirm,
Dired deletes the flagged files, then deletes their lines from the text
of the Dired buffer. The shortened Dired buffer remains selected.
If you answer no or quit with C-g when asked to confirm, you return immediately to Dired, with the deletion flags still present in the buffer, and no files actually deleted.
The #, ~, &, and . commands flag many files for deletion, based on their file names. These commands are useful precisely because they do not themselves delete any files; you can remove the deletion flags from any flagged files that you really wish to keep.
& (dired-flag-garbage-files) flags files whose names
match the regular expression specified by the variable
dired-garbage-files-regexp. By default, this matches certain
files produced by TeX, ‘.bak’ files, and the ‘.orig’ and
‘.rej’ files produced by patch.
# (dired-flag-auto-save-files) flags for deletion all
files whose names look like auto-save files (see Auto Save)—that
is, files whose names begin and end with ‘#’.
~ (dired-flag-backup-files) flags for deletion all files
whose names say they are backup files (see Backup)—that is, files
whose names end in ‘~’.
. (period, dired-clean-directory) flags just some of the
backup files for deletion: all but the oldest few and newest few backups
of any one file. Normally dired-kept-versions (not
kept-new-versions; that applies only when saving) specifies the
number of newest versions of each file to keep, and
kept-old-versions specifies the number of oldest versions to
keep.
Period with a positive numeric argument, as in C-u 3 .,
specifies the number of newest versions to keep, overriding
dired-kept-versions. A negative numeric argument overrides
kept-old-versions, using minus the value of the argument to
specify the number of oldest versions of each file to keep.
The % d command flags all files whose names match a specified
regular expression (dired-flag-files-regexp). Only the
non-directory part of the file name is used in matching. You can use
‘^’ and ‘$’ to anchor matches. You can exclude subdirectories
by hiding them (see Hiding Subdirectories).
There are several Dired commands for visiting or examining the files listed in the Dired buffer. All of them apply to the current line's file; if that file is really a directory, these commands invoke Dired on that subdirectory (making a separate Dired buffer).
dired-find-file). See Visiting.
dired-find-file-other-window). The Dired buffer remains visible
in the first window. This is like using C-x 4 C-f to visit the
file. See Windows.
dired-display-file).
dired-mouse-find-file-other-window). This uses another window
to display the file, like the o command.
dired-view-file). Viewing a file with view-file is
like visiting it, but is slanted toward moving around in the file
conveniently and does not allow changing the file. See View File.
dired-up-directory). This is more convenient than moving to
the parent directory's line and typing f there.
Instead of flagging a file with ‘D’, you can mark the file with some other character (usually ‘*’). Most Dired commands to operate on files use the files marked with ‘*’, the exception being x which deletes the flagged files.
Here are some commands for marking with ‘*’, or for unmarking or operating on marks. (See Dired Deletion, for commands to flag and unflag files.)
dired-mark). With a numeric
argument n, mark the next n files starting with the current
file. (If n is negative, mark the previous −n
files.)
dired-mark-executables). With a numeric argument, unmark all
those files.
dired-mark-symlinks).
With a numeric argument, unmark all those files.
dired-mark-directories). With a numeric
argument, unmark all those files.
dired-mark-subdir-files).
dired-unmark).
dired-unmark-backward).
dired-unmark-all-marks).
dired-unmark-all-files). The argument is a single
character—do not use <RET> to terminate it. See the description
of the * c command below, which lets you replace one mark
character with another.
With a numeric argument, this command queries about each marked file,
asking whether to remove its mark. You can answer y meaning yes,
n meaning no, or ! to remove the marks from the remaining
files without asking about them.
dired-next-marked-file)
A file is “marked” if it has any kind of mark.
dired-prev-marked-file)
dired-toggle-marks): files marked with ‘*’
become unmarked, and unmarked files are marked with ‘*’. Files
marked in any other way are not affected.
dired-change-marks).
This command is the primary way to create or use marks other than
‘*’ or ‘D’. The arguments are single characters—do not use
<RET> to terminate them.
You can use almost any character as a mark character by means of this command, to distinguish various classes of files. If old-markchar is a space (‘ ’), then the command operates on all unmarked files; if new-markchar is a space, then the command unmarks the files it acts on.
To illustrate the power of this command, here is how to put ‘D’ flags on all the files that have no marks, while unflagging all those that already have ‘D’ flags:
* c D t * c SPC D * c t SPC
This assumes that no files were already marked with ‘t’.
dired-mark-files-regexp). This command is like
% d, except that it marks files with ‘*’ instead of flagging
with ‘D’. See Flagging Many Files.
Only the non-directory part of the file name is used in matching. Use
‘^’ and ‘$’ to anchor matches. Exclude subdirectories by
hiding them (see Hiding Subdirectories).
dired-mark-files-containing-regexp). This command is like
% m, except that it searches the file contents instead of the file
name.
dired-undo). This command does not revert the
actual file operations, nor recover lost files! It just undoes
changes in the buffer itself. For example, if used after renaming one
or more files, dired-undo restores the original names, which
will get the Dired buffer out of sync with the actual contents of the
directory.
This section describes the basic Dired commands to operate on one file or several files. All of these commands are capital letters; all of them use the minibuffer, either to read an argument or to ask for confirmation, before they act. All of them give you several ways to specify which files to manipulate:
Commands which ask for a destination directory, such as those which
copy and rename files or create links for them, try to guess the default
target directory for the operation. Normally, they suggest the Dired
buffer's default directory, but if the variable dired-dwim-target
is non-nil, and if there is another Dired buffer displayed in the
next window, that other buffer's directory is suggested instead.
Here are the file-manipulating commands that operate on files in this way. (Some other Dired commands, such as ! and the ‘%’ commands, also use these conventions to decide which files to work on.)
dired-do-copy). The argument new
is the directory to copy into, or (if copying a single file) the new
name.
If dired-copy-preserve-time is non-nil, then copying with
this command sets the modification time of the new file to be the same
as that of the old file.
The variable dired-recursive-copies controls whether
directories are copied recursively. The default is to not copy
recursively, which means that directories cannot be copied.
dired-do-delete). Like the other
commands in this section, this command operates on the marked
files, or the next n files. By contrast, x
(dired-do-flagged-delete) deletes all flagged files.
dired-do-rename). The argument
new is the directory to rename into, or (if renaming a single
file) the new name.
Dired automatically changes the visited file name of buffers associated with renamed files so that they refer to the new names.
dired-do-hardlink). The
argument new is the directory to make the links in, or (if making
just one link) the name to give the link.
dired-do-symlink).
The argument new is the directory to make the links in, or (if
making just one link) the name to give the link.
dired-do-chmod). This uses the chmod program, so
modespec can be any argument that chmod can handle.
dired-do-chgrp).
dired-do-chown). (On most systems, only the superuser can do
this.)
The variable dired-chown-program specifies the name of the
program to use to do the work (different systems put chown in
different places).
dired-do-touch).
dired-do-print). You must specify the
command to print them with, but the minibuffer starts out with a
suitable guess made using the variables lpr-command and
lpr-switches (the same variables that lpr-buffer uses;
see Printing).
dired-do-compress). If the file
appears to be a compressed file already, it is uncompressed instead.
dired-do-load).
See Lisp Libraries.
dired-do-byte-compile). See Byte Compilation.
dired-do-search).
This command is a variant of tags-search. The search stops at
the first match it finds; use M-, to resume the search and find
the next match. See Tags Search.
query-replace-regexp on each of the specified files,
replacing matches for regexp with the string
to (dired-do-query-replace-regexp).
This command is a variant of tags-query-replace. If you exit the
query replace loop, you can use M-, to resume the scan and replace
more matches. See Tags Search.
One special file-operation command is +
(dired-create-directory). This command reads a directory name and
creates the directory if it does not already exist.
The Dired command ! (dired-do-shell-command) reads a shell
command string in the minibuffer and runs that shell command on all the
specified files. X is a synonym for !. You can specify the
files to operate on in the usual ways for Dired commands
(see Operating on Files). There are two ways of applying a shell
command to multiple files:
Thus, ! tar cf foo.tar * <RET> runs tar on the entire
list of file names, putting them into one tar file foo.tar.
If you want to use ‘*’ as a shell wildcard with whitespace around it, write ‘*""’. In the shell, this is equivalent to ‘*’; but since the ‘*’ is not surrounded by whitespace, Dired does not treat it specially.
For example, ! uudecode <RET> runs uudecode on each
file.
To iterate over the file names in a more complicated fashion, use an explicit shell loop. For example, here is how to uuencode each file, making the output file name by appending ‘.uu’ to the input file name:
for file in * ; do uuencode "$file" "$file" >"$file".uu; done
The working directory for the shell command is the top-level directory of the Dired buffer.
The ! command does not attempt to update the Dired buffer to show new or modified files, because it doesn't really understand shell commands, and does not know what files the shell command changed. Use the g command to update the Dired buffer (see Dired Updating).
This section describes Dired commands which alter file names in a systematic way.
Like the basic Dired file-manipulation commands (see Operating on Files), the commands described here operate either on the next n files, or on all files marked with ‘*’, or on the current file. (To mark files, use the commands described in Marks vs Flags.)
All of the commands described in this section work interactively: they ask you to confirm the operation for each candidate file. Thus, you can select more files than you actually need to operate on (e.g., with a regexp that matches many files), and then refine the selection by typing y or n when the command prompts for confirmation.
dired-upcase). If the old file names are Foo
and bar, the new names are FOO and BAR.
dired-downcase). If the old file names are Foo and
bar, the new names are foo and bar.
The four regular-expression substitution commands effectively perform a search-and-replace on the selected file names in the Dired buffer. They read two arguments: a regular expression from, and a substitution pattern to.
The commands match each “old” file name against the regular
expression from, and then replace the matching part with to.
You can use ‘\&’ and ‘\digit’ in to to refer to
all or part of what the pattern matched in the old file name, as in
replace-regexp (see Regexp Replace). If the regular expression
matches more than once in a file name, only the first match is replaced.
For example, % R ^.*$ <RET> x-\& <RET> renames each selected file by prepending ‘x-’ to its name. The inverse of this, removing ‘x-’ from the front of each file name, is also possible: one method is % R ^x-\(.*\)$ <RET> \1 <RET>; another is % R ^x- <RET> <RET>. (Use ‘^’ and ‘$’ to anchor matches that should span the whole filename.)
Normally, the replacement process does not consider the files' directory names; it operates on the file name within the directory. If you specify a numeric argument of zero, then replacement affects the entire absolute file name including directory name. (Non-zero argument specifies the number of files to operate on.)
Often you will want to select the set of files to operate on using the same regexp that you will use to operate on them. To do this, mark those files with % m regexp <RET>, then use the same regular expression in the command to operate on the files. To make this easier, the % commands to operate on files use the last regular expression specified in any % command as a default.
Here are two Dired commands that compare specified files using
diff.
diff program (dired-diff). The
file at the mark is the first argument of diff, and the file at
point is the second argument. Use C-<SPC>
(set-mark-command) to set the mark at the first file's line
(see Setting Mark), since dired-diff ignores the files marked
with the Dired's m command.
dired-backup-diff). If the current file is itself a backup,
compare it with the file it is a backup of; this way, you can compare
a file with any backup version of your choice.
The backup file is the first file given to diff.
A Dired buffer displays just one directory in the normal case; but you can optionally include its subdirectories as well.
The simplest way to include multiple directories in one Dired buffer is
to specify the options ‘-lR’ for running ls. (If you give a
numeric argument when you run Dired, then you can specify these options
in the minibuffer.) That produces a recursive directory listing showing
all subdirectories at all levels.
But usually all the subdirectories are too many; usually you will prefer to include specific subdirectories only. You can do this with the i command:
Use the i (dired-maybe-insert-subdir) command on a line
that describes a file which is a directory. It inserts the contents of
that directory into the same Dired buffer, and moves there. Inserted
subdirectory contents follow the top-level directory of the Dired
buffer, just as they do in ‘ls -lR’ output.
If the subdirectory's contents are already present in the buffer, the i command just moves to it.
In either case, i sets the Emacs mark before moving, so C-u C-<SPC> takes you back to the old position in the buffer (the line describing that subdirectory).
Use the l command (dired-do-redisplay) to update the
subdirectory's contents. Use C-u k on the subdirectory header
line to delete the subdirectory. See Dired Updating.
When a Dired buffer lists subdirectories, you can use the page motion commands C-x [ and C-x ] to move by entire directories (see Pages).
The following commands move across, up and down in the tree of directories within one Dired buffer. They move to directory header lines, which are the lines that give a directory's name, at the beginning of the directory's contents.
dired-next-subdir).
dired-prev-subdir).
dired-tree-up).
dired-tree-down).
dired-prev-dirline).
These lines are the ones that describe a directory as a file in its
parent directory.
dired-prev-dirline).
Hiding a subdirectory means to make it invisible, except for its header line, via selective display (see Selective Display).
dired-hide-subdir). A numeric argument serves
as a repeat count.
dired-hide-all). Or, if any subdirectory is currently
hidden, make all subdirectories visible again. You can use this command
to get an overview in very deep directory trees or to move quickly to
subdirectories far away.
Ordinary Dired commands never consider files inside a hidden subdirectory. For example, the commands to operate on marked files ignore files in hidden directories even if they are marked. Thus you can use hiding to temporarily exclude subdirectories from operations without having to remove the markers.
This section describes commands to update the Dired buffer to reflect outside (non-Dired) changes in the directories and files, and to delete part of the Dired buffer.
revert-buffer).
dired-do-redisplay).
dired-do-kill-lines).
dired-sort-toggle-or-edit).
dired-listing-switches.
Type g (revert-buffer) to update the contents of the
Dired buffer, based on changes in the files and directories listed.
This preserves all marks except for those on files that have vanished.
Hidden subdirectories are updated but remain hidden.
To update only some of the files, type l
(dired-do-redisplay). Like the Dired file-operating commands,
this command operates on the next n files (or previous
−n files), or on the marked files if any, or on the
current file. Updating the files means reading their current status,
then updating their lines in the buffer to indicate that status.
If you use l on a subdirectory header line, it updates the contents of the corresponding subdirectory.
To delete the specified file lines from the buffer—not
delete the files—type k (dired-do-kill-lines). Like
the file-operating commands, this command operates on the next n
files, or on the marked files if any; but it does not operate on the
current file as a last resort.
If you use k with a numeric prefix argument to kill the line for a file that is a directory, which you have inserted in the Dired buffer as a subdirectory, then this deletes that subdirectory from the buffer as well. Typing C-u k on the header line for a subdirectory is another way to delete a subdirectory from the Dired buffer.
The g command brings back any individual lines that you have killed in this way, but not subdirectories—you must use i to reinsert a subdirectory.
The files in a Dired buffers are normally listed in alphabetical order
by file names. Alternatively Dired can sort them by date/time. The
Dired command s (dired-sort-toggle-or-edit) switches
between these two sorting modes. The mode line in a Dired buffer
indicates which way it is currently sorted—by name, or by date.
C-u s switches <RET> lets you specify a new value for
dired-listing-switches.
find
You can select a set of files for display in a Dired buffer more
flexibly by using the find utility to choose the files.
To search for files with names matching a wildcard pattern use M-x find-name-dired. It reads arguments directory and pattern, and chooses all the files in directory or its subdirectories whose individual names match pattern.
The files thus chosen are displayed in a Dired buffer in which the ordinary Dired commands are available.
If you want to test the contents of files, rather than their names,
use M-x find-grep-dired. This command reads two minibuffer
arguments, directory and regexp; it chooses all the files in
directory or its subdirectories that contain a match for
regexp. It works by running the programs find and
grep. See also M-x grep-find, in Grep Searching.
Remember to write the regular expression for grep, not for Emacs.
(An alternative method of showing files whose contents match a given
regexp is the % g regexp command, see Marks vs Flags.)
The most general command in this series is M-x find-dired, which
lets you specify any condition that find can test. It takes two
minibuffer arguments, directory and find-args; it runs
find in directory, passing find-args to tell
find what condition to test. To use this command, you need to
know how to use find.
The format of listing produced by these commands is controlled by the
variable find-ls-option, whose default value specifies using
options ‘-ld’ for ls. If your listings are corrupted, you
may need to change the value of this variable.
M-x locate provides a similar interface to the locate
program. M-x locate-with-filter is similar, but keeps only lines
matching a given regular expression.
These buffers don't work entirely like ordinary Dired buffers. File operations work, but do not always automatically update the buffer. Reverting the buffer with g deletes all inserted subdirectories, and erases all flags and marks.
Wdired is a special mode that allows you to perform file operations by editing the Dired buffer directly (the “W” in “Wdired” stands for “writable”.) To enter Wdired mode, type M-x wdired-change-to-wdired-mode while in a Dired buffer. Alternatively, use ‘Edit File Names’ in the ‘Immediate’ menu bar menu.
While in Wdired mode, you can rename files by editing the file names
displayed in the Dired buffer. All the ordinary Emacs editing
commands, including rectangle operations and query-replace, are
available for this. Once you are done editing, type C-c C-c
(wdired-finish-edit). This applies your changes and switches
back to ordinary Dired mode.
Apart from simply renaming files, you can move a file to another directory by typing in the new file name (either absolute or relative). To mark a file for deletion, delete the entire filename. To change the target of a symbolic link, just edit the target name displayed next to the link name.
The rest of the text in the buffer, such as the file sizes and
modification dates, is marked read-only, so you can't edit it.
However, if you set wdired-allow-to-change-permissions to
t, the file permission bits can also be edited. For example,
you can change ‘-rw-r--r--’ to ‘-rw-rw-rw-’ to make a file
world-writable. These changes also take effect when you type C-c
C-c.
The w command (dired-copy-filename-as-kill) puts the
names of the marked (or next n) files into the kill ring, as if
you had killed them with C-w. The names are separated by a space.
The main purpose of this command is so that you can yank the file names into arguments for other Emacs commands. It also displays what was pushed onto the kill ring, so you can use it to display the list of currently marked files in the echo area. With a zero prefix argument, this uses the absolute file name of each marked file. With just C-u as the prefix argument, it uses file names relative to the Dired buffer's default directory. (This can still contain slashes if in a subdirectory.) As a special case, if point is on a directory headerline, w gives you the absolute name of that directory. Any prefix argument or marked files are ignored in this case.
The command M-x dired-compare-directories is used to compare the current Dired buffer with another directory. It marks all the files that are “different” between the two directories. It puts these marks in all Dired buffers where these files are listed, which of course includes the current buffer.
The default comparison method (used if you type <RET> at the
prompt) is to compare just the file names—each file name that does
not appear in the other directory is “different”. You can specify
more stringent comparisons by entering a Lisp expression, which can
refer to the variables size1 and size2, the respective
file sizes; mtime1 and mtime2, the last modification
times in seconds, as floating point numers; and fa1 and
fa2, the respective file attribute lists (as returned by the
function file-attributes). This expression is evaluated for
each pair of like-named files, and if the expression's value is
non-nil, those files are considered “different”.
For instance, M-x dired-compare-directories <RET> (>
mtime1 mtime2) <RET> marks files newer in this directory than in
the other, and marks files older in the other directory than in this
one. It also marks files with no counterpart, in both directories, as
always.
On the X window system, Emacs supports the “drag and drop” protocol. You can drag a file object from another program, and drop it onto a Dired buffer; this either moves, copies, or creates a link to the file in that directory. Precisely which action is taken is determined by the originating program. Dragging files out of a Dired buffer is currently not supported.
Emacs provides the functions of a desk calendar, with a diary of planned or past events. It also has facilities for managing your appointments, and keeping track of how much time you spend working on certain projects.
To enter the calendar, type M-x calendar; this displays a three-month calendar centered on the current month, with point on the current date. With a numeric argument, as in C-u M-x calendar, it prompts you for the month and year to be the center of the three-month calendar. The calendar uses its own buffer, whose major mode is Calendar mode.
Mouse-2 in the calendar brings up a menu of operations on a particular date; Mouse-3 brings up a menu of commonly used calendar features that are independent of any particular date. To exit the calendar, type q.
The basic features of the Calendar/Diary are described here. see Advanced Calendar/Diary Usage, for information about more specialized features.
Calendar mode lets you move through the calendar in logical units of time such as days, weeks, months, and years. If you move outside the three months originally displayed, the calendar display “scrolls” automatically through time to make the selected date visible. Moving to a date lets you view its holidays or diary entries, or convert it to other calendars; moving longer time periods is also useful simply to scroll the calendar.
The commands for movement in the calendar buffer parallel the commands for movement in text. You can move forward and backward by days, weeks, months, and years.
calendar-forward-day).
calendar-backward-day).
calendar-forward-week).
calendar-backward-week).
calendar-forward-month).
calendar-backward-month).
calendar-forward-year).
calendar-backward-year).
The day and week commands are natural analogues of the usual Emacs commands for moving by characters and by lines. Just as C-n usually moves to the same column in the following line, in Calendar mode it moves to the same day in the following week. And C-p moves to the same day in the previous week.
The arrow keys are equivalent to C-f, C-b, C-n and C-p, just as they normally are in other modes.
The commands for motion by months and years work like those for weeks, but move a larger distance. The month commands M-} and M-{ move forward or backward by an entire month's time. The year commands C-x ] and C-x [ move forward or backward a whole year.
The easiest way to remember these commands is to consider months and years analogous to paragraphs and pages of text, respectively. But the commands themselves are not quite analogous. The ordinary Emacs paragraph commands move to the beginning or end of a paragraph, whereas these month and year commands move by an entire month or an entire year, which usually involves skipping across the end of a month or year.
All these commands accept a numeric argument as a repeat count. For convenience, the digit keys and the minus sign specify numeric arguments in Calendar mode even without the Meta modifier. For example, 100 C-f moves point 100 days forward from its present location.
A week (or month, or year) is not just a quantity of days; we think of weeks (months, years) as starting on particular dates. So Calendar mode provides commands to move to the beginning or end of a week, month or year:
calendar-beginning-of-week).
calendar-end-of-week).
calendar-beginning-of-month).
calendar-end-of-month).
calendar-beginning-of-year).
calendar-end-of-year).
These commands also take numeric arguments as repeat counts, with the repeat count indicating how many weeks, months, or years to move backward or forward.
By default, weeks begin on Sunday. To make them begin on Monday
instead, set the variable calendar-week-start-day to 1.
Calendar mode provides commands for moving to a particular date specified in various ways.
calendar-goto-date).
calendar-goto-day-of-year).
calendar-goto-iso-week).
calendar-other-month).
calendar-goto-today).
g d (calendar-goto-date) prompts for a year, a month, and a day
of the month, and then moves to that date. Because the calendar includes all
dates from the beginning of the current era, you must type the year in its
entirety; that is, type ‘1990’, not ‘90’.
g D (calendar-goto-day-of-year) prompts for a year and
day number, and moves to that date. Negative day numbers count
backward from the end of the year. g w
(calendar-goto-iso-week) prompts for a year and week number,
and moves to that week.
o (calendar-other-month) prompts for a month and year,
then centers the three-month calendar around that month.
You can return to today's date with .
(calendar-goto-today).
The calendar display scrolls automatically through time when you move out of the visible portion. You can also scroll it manually. Imagine that the calendar window contains a long strip of paper with the months on it. Scrolling the calendar means moving the strip horizontally, so that new months become visible in the window.
scroll-calendar-left).
scroll-calendar-right).
scroll-calendar-left-three-months).
scroll-calendar-right-three-months).
The most basic calendar scroll commands scroll by one month at a time. This means that there are two months of overlap between the display before the command and the display after. < scrolls the calendar contents one month to the left; that is, it moves the display forward in time. > scrolls the contents to the right, which moves backwards in time.
The commands C-v and M-v scroll the calendar by an entire “screenful”—three months—in analogy with the usual meaning of these commands. C-v makes later dates visible and M-v makes earlier dates visible. These commands take a numeric argument as a repeat count; in particular, since C-u multiplies the next command by four, typing C-u C-v scrolls the calendar forward by a year and typing C-u M-v scrolls the calendar backward by a year.
The function keys <NEXT> and <PRIOR> are equivalent to C-v and M-v, just as they are in other modes.
calendar-count-days-region).
To determine the number of days in the region, type M-=
(calendar-count-days-region). The numbers of days shown is
inclusive; that is, it includes the days specified by mark and
point.
calendar-print-day-of-year).
redraw-calendar).
scroll-other-window).
scroll-other-window-down).
exit-calendar).
To display the number of days elapsed since the start of the year, or
the number of days remaining in the year, type the p d command
(calendar-print-day-of-year). This displays both of those
numbers in the echo area. The number of days elapsed includes the
selected date. The number of days remaining does not include that
date.
If the calendar window text gets corrupted, type C-c C-l
(redraw-calendar) to redraw it. (This can only happen if you use
non-Calendar-mode editing commands.)
In Calendar mode, you can use SPC (scroll-other-window)
and DEL (scroll-other-window-down) to scroll the other
window up or down, respectively. This is handy when you display a list
of holidays or diary entries in another window.
To exit from the calendar, type q (exit-calendar). This
buries all buffers related to the calendar, selecting other buffers.
(If a frame contains a dedicated calendar window, exiting from the
calendar iconifies that frame.)
The Calendar LaTeX commands produce a buffer of LaTeX code that prints as a calendar. Depending on the command you use, the printed calendar covers the day, week, month or year that point is in.
cal-tex-cursor-month).
cal-tex-cursor-month-landscape).
cal-tex-cursor-day).
cal-tex-cursor-week).
cal-tex-cursor-week2).
cal-tex-cursor-week-iso).
cal-tex-cursor-week-monday).
cal-tex-cursor-filofax-2week).
cal-tex-cursor-filofax-week).
cal-tex-cursor-year).
cal-tex-cursor-year-landscape).
cal-tex-cursor-filofax-year).
Some of these commands print the calendar sideways (in “landscape mode”), so it can be wider than it is long. Some of them use Filofax paper size (3.75in x 6.75in). All of these commands accept a prefix argument which specifies how many days, weeks, months or years to print (starting always with the selected one).
If the variable cal-tex-holidays is non-nil (the default),
then the printed calendars show the holidays in calendar-holidays.
If the variable cal-tex-diary is non-nil (the default is
nil), diary entries are included also (in weekly and monthly
calendars only). If the variable cal-tex-rules is non-nil
(the default is nil), the calendar displays ruled pages
in styles that have sufficient room.
The Emacs calendar knows about all major and many minor holidays, and can display them.
calendar-cursor-holidays).
mark-calendar-holidays).
calendar-unmark).
list-calendar-holidays).
To see if any holidays fall on a given date, position point on that
date in the calendar window and use the h command. Alternatively,
click on that date with Mouse-2 and then choose Holidays
from the menu that appears. Either way, this displays the holidays for
that date, in the echo area if they fit there, otherwise in a separate
window. If the variable view-calendar-holidays-initially is
non-nil, creating the calendar displays holidays in this way.
To view the distribution of holidays for all the dates shown in the
calendar, use the x command. This displays the dates that are
holidays in a different face (or places a ‘*’ after these dates, if
display with multiple faces is not available). see calendar-holiday-marker. The command applies
both to the currently visible months and to other months that
subsequently become visible by scrolling. To turn marking off and erase
the current marks, type u, which also erases any diary marks
(see Diary). If the variable mark-holidays-in-calendar is
non-nil, creating or updating the calendar marks holidays
automatically.
To get even more detailed information, use the a command, which displays a separate buffer containing a list of all holidays in the current three-month range. You can use <SPC> and <DEL> in the calendar window to scroll that list up and down, respectively.
The command M-x holidays displays the list of holidays for the current month and the preceding and succeeding months; this works even if you don't have a calendar window. If you want the list of holidays centered around a different month, use C-u M-x holidays, which prompts for the month and year.
The holidays known to Emacs include United States holidays and the major Christian, Jewish, and Islamic holidays; also the solstices and equinoxes.
The command M-x list-holidays displays the list of holidays for a range of years. This function asks you for the starting and stopping years, and allows you to choose all the holidays or one of several categories of holidays. You can use this command even if you don't have a calendar window.
The dates used by Emacs for holidays are based on current practice, not historical fact. Historically, for instance, the start of daylight savings time and even its existence have varied from year to year, but present United States law mandates that daylight savings time begins on the first Sunday in April. When the daylight savings rules are set up for the United States, Emacs always uses the present definition, even though it is wrong for some prior years.
Special calendar commands can tell you, to within a minute or two, the times of sunrise and sunset for any date.
calendar-sunrise-sunset).
Within the calendar, to display the local times of sunrise and sunset in the echo area, move point to the date you want, and type S. Alternatively, click Mouse-2 on the date, then choose ‘Sunrise/sunset’ from the menu that appears. The command M-x sunrise-sunset is available outside the calendar to display this information for today's date or a specified date. To specify a date other than today, use C-u M-x sunrise-sunset, which prompts for the year, month, and day.
You can display the times of sunrise and sunset for any location and any date with C-u C-u M-x sunrise-sunset. This asks you for a longitude, latitude, number of minutes difference from Coordinated Universal Time, and date, and then tells you the times of sunrise and sunset for that location on that date.
Because the times of sunrise and sunset depend on the location on earth, you need to tell Emacs your latitude, longitude, and location name before using these commands. Here is an example of what to set:
(setq calendar-latitude 40.1)
(setq calendar-longitude -88.2)
(setq calendar-location-name "Urbana, IL")
Use one decimal place in the values of calendar-latitude and
calendar-longitude.
Your time zone also affects the local time of sunrise and sunset. Emacs usually gets time zone information from the operating system, but if these values are not what you want (or if the operating system does not supply them), you must set them yourself. Here is an example:
(setq calendar-time-zone -360)
(setq calendar-standard-time-zone-name "CST")
(setq calendar-daylight-time-zone-name "CDT")
The value of calendar-time-zone is the number of minutes
difference between your local standard time and Coordinated Universal
Time (Greenwich time). The values of
calendar-standard-time-zone-name and
calendar-daylight-time-zone-name are the abbreviations used in
your time zone. Emacs displays the times of sunrise and sunset
corrected for daylight savings time. See Daylight Savings,
for how daylight savings time is determined.
As a user, you might find it convenient to set the calendar location variables for your usual physical location in your .emacs file. And when you install Emacs on a machine, you can create a default.el file which sets them properly for the typical location of most users of that machine. See Init File.
These calendar commands display the dates and times of the phases of the moon (new moon, first quarter, full moon, last quarter). This feature is useful for debugging problems that “depend on the phase of the moon.”
calendar-phases-of-moon).
Within the calendar, use the M command to display a separate buffer of the phases of the moon for the current three-month range. The dates and times listed are accurate to within a few minutes.
Outside the calendar, use the command M-x phases-of-moon to display the list of the phases of the moon for the current month and the preceding and succeeding months. For information about a different month, use C-u M-x phases-of-moon, which prompts for the month and year.
The dates and times given for the phases of the moon are given in
local time (corrected for daylight savings, when appropriate); but if
the variable calendar-time-zone is void, Coordinated Universal
Time (the Greenwich time zone) is used. See Daylight Savings.
The Emacs calendar displayed is always the Gregorian calendar, sometimes called the “new style” calendar, which is used in most of the world today. However, this calendar did not exist before the sixteenth century and was not widely used before the eighteenth century; it did not fully displace the Julian calendar and gain universal acceptance until the early twentieth century. The Emacs calendar can display any month since January, year 1 of the current era, but the calendar displayed is the Gregorian, even for a date at which the Gregorian calendar did not exist.
While Emacs cannot display other calendars, it can convert dates to and from several other calendars.
The ISO commercial calendar is used largely in Europe.
The Julian calendar, named after Julius Caesar, was the one used in Europe throughout medieval times, and in many countries up until the nineteenth century.
Astronomers use a simple counting of days elapsed since noon, Monday, January 1, 4713 B.C. on the Julian calendar. The number of days elapsed is called the Julian day number or the Astronomical day number.
The Hebrew calendar is used by tradition in the Jewish religion. The Emacs calendar program uses the Hebrew calendar to determine the dates of Jewish holidays. Hebrew calendar dates begin and end at sunset.
The Islamic calendar is used in many predominantly Islamic countries. Emacs uses it to determine the dates of Islamic holidays. There is no universal agreement in the Islamic world about the calendar; Emacs uses a widely accepted version, but the precise dates of Islamic holidays often depend on proclamation by religious authorities, not on calculations. As a consequence, the actual dates of observance can vary slightly from the dates computed by Emacs. Islamic calendar dates begin and end at sunset.
The French Revolutionary calendar was created by the Jacobins after the 1789 revolution, to represent a more secular and nature-based view of the annual cycle, and to install a 10-day week in a rationalization measure similar to the metric system. The French government officially abandoned this calendar at the end of 1805.
The Maya of Central America used three separate, overlapping calendar systems, the long count, the tzolkin, and the haab. Emacs knows about all three of these calendars. Experts dispute the exact correlation between the Mayan calendar and our calendar; Emacs uses the Goodman-Martinez-Thompson correlation in its calculations.
The Copts use a calendar based on the ancient Egyptian solar calendar. Their calendar consists of twelve 30-day months followed by an extra five-day period. Once every fourth year they add a leap day to this extra period to make it six days. The Ethiopic calendar is identical in structure, but has different year numbers and month names.
The Persians use a solar calendar based on a design of Omar Khayyam. Their calendar consists of twelve months of which the first six have 31 days, the next five have 30 days, and the last has 29 in ordinary years and 30 in leap years. Leap years occur in a complicated pattern every four or five years. The calendar implemented here is the arithmetical Persian calendar championed by Birashk, based on a 2,820-year cycle. It differs from the astronomical Persian calendar, which is based on astronomical events. As of this writing the first future discrepancy is projected to occur on March 20, 2025. It is currently not clear what the official calendar of Iran will be that far into the future.
The Chinese calendar is a complicated system of lunar months arranged into solar years. The years go in cycles of sixty, each year containing either twelve months in an ordinary year or thirteen months in a leap year; each month has either 29 or 30 days. Years, ordinary months, and days are named by combining one of ten “celestial stems” with one of twelve “terrestrial branches” for a total of sixty names that are repeated in a cycle of sixty.
The following commands describe the selected date (the date at point) in various other calendar systems:
calendar-print-iso-date).
calendar-print-julian-date).
calendar-print-astro-day-number).
calendar-print-hebrew-date).
calendar-print-islamic-date).
calendar-print-french-date).
calendar-print-chinese-date).
calendar-print-coptic-date).
calendar-print-ethiopic-date).
calendar-print-persian-date).
calendar-print-mayan-date).
If you are using X, the easiest way to translate a date into other calendars is to click on it with Mouse-2, then choose Other calendars from the menu that appears. This displays the equivalent forms of the date in all the calendars Emacs understands, in the form of a menu. (Choosing an alternative from this menu doesn't actually do anything—the menu is used only for display.)
Otherwise, move point to the date you want to convert, then type the appropriate command starting with p from the table above. The prefix p is a mnemonic for “print,” since Emacs “prints” the equivalent date in the echo area.
You can use the other supported calendars to specify a date to move to. This section describes the commands for doing this using calendars other than Mayan; for the Mayan calendar, see the following section.
calendar-goto-iso-date).
calendar-goto-iso-week).
calendar-goto-julian-date).
calendar-goto-astro-day-number).
calendar-goto-hebrew-date).
calendar-goto-islamic-date).
calendar-goto-french-date).
calendar-goto-chinese-date).
calendar-goto-persian-date).
calendar-goto-coptic-date).
calendar-goto-ethiopic-date).
These commands ask you for a date on the other calendar, move point to the Gregorian calendar date equivalent to that date, and display the other calendar's date in the echo area. Emacs uses strict completion (see Completion) whenever it asks you to type a month name, so you don't have to worry about the spelling of Hebrew, Islamic, or French names.
One common question concerning the Hebrew calendar is the computation of the anniversary of a date of death, called a “yahrzeit.” The Emacs calendar includes a facility for such calculations. If you are in the calendar, the command M-x list-yahrzeit-dates asks you for a range of years and then displays a list of the yahrzeit dates for those years for the date given by point. If you are not in the calendar, this command first asks you for the date of death and the range of years, and then displays the list of yahrzeit dates.
Here are the commands to select dates based on the Mayan calendar:
calendar-goto-mayan-long-count-date).
calendar-next-tzolkin-date).
calendar-previous-tzolkin-date).
calendar-next-haab-date).
calendar-previous-haab-date).
calendar-next-calendar-round-date).
calendar-previous-calendar-round-date).
To understand these commands, you need to understand the Mayan calendars. The long count is a counting of days with these units:
1 kin = 1 day 1 uinal = 20 kin 1 tun = 18 uinal
1 katun = 20 tun 1 baktun = 20 katun
Thus, the long count date 12.16.11.16.6 means 12 baktun, 16 katun, 11 tun, 16 uinal, and 6 kin. The Emacs calendar can handle Mayan long count dates as early as 7.17.18.13.3, but no earlier. When you use the g m l command, type the Mayan long count date with the baktun, katun, tun, uinal, and kin separated by periods.
The Mayan tzolkin calendar is a cycle of 260 days formed by a pair of independent cycles of 13 and 20 days. Since this cycle repeats endlessly, Emacs provides commands to move backward and forward to the previous or next point in the cycle. Type g m p t to go to the previous tzolkin date; Emacs asks you for a tzolkin date and moves point to the previous occurrence of that date. Similarly, type g m n t to go to the next occurrence of a tzolkin date.
The Mayan haab calendar is a cycle of 365 days arranged as 18 months of 20 days each, followed a 5-day monthless period. Like the tzolkin cycle, this cycle repeats endlessly, and there are commands to move backward and forward to the previous or next point in the cycle. Type g m p h to go to the previous haab date; Emacs asks you for a haab date and moves point to the previous occurrence of that date. Similarly, type g m n h to go to the next occurrence of a haab date.
The Maya also used the combination of the tzolkin date and the haab date. This combination is a cycle of about 52 years called a calendar round. If you type g m p c, Emacs asks you for both a haab and a tzolkin date and then moves point to the previous occurrence of that combination. Use g m n c to move point to the next occurrence of a combination. These commands signal an error if the haab/tzolkin date combination you have typed is impossible.
Emacs uses strict completion (see Strict Completion) whenever it asks you to type a Mayan name, so you don't have to worry about spelling.
The Emacs diary keeps track of appointments or other events on a daily basis, in conjunction with the calendar. To use the diary feature, you must first create a diary file containing a list of events and their dates. Then Emacs can automatically pick out and display the events for today, for the immediate future, or for any specified date.
The name of the diary file is specified by the variable
diary-file; ~/diary is the default. A sample diary file
is (note that the file format is essentially the same as that used by
the external shell utility ‘calendar’):
12/22/1988 Twentieth wedding anniversary!!
&1/1. Happy New Year!
10/22 Ruth's birthday.
* 21, *: Payday
Tuesday--weekly meeting with grad students at 10am
Supowit, Shen, Bitner, and Kapoor to attend.
1/13/89 Friday the thirteenth!!
&thu 4pm squash game with Lloyd.
mar 16 Dad's birthday
April 15, 1989 Income tax due.
&* 15 time cards due.
This example uses extra spaces to align the event descriptions of most of the entries. Such formatting is purely a matter of taste.
Although you probably will start by creating a diary manually, Emacs provides a number of commands to let you view, add, and change diary entries.
Once you have created a diary file, you can use the calendar to view it. You can also view today's events outside of Calendar mode.
view-diary-entries).
show-all-diary-entries).
mark-diary-entries).
calendar-unmark).
Displaying the diary entries with d shows in a separate window the diary entries for the selected date in the calendar. The mode line of the new window shows the date of the diary entries and any holidays that fall on that date. If you specify a numeric argument with d, it shows all the diary entries for that many successive days. Thus, 2 d displays all the entries for the selected date and for the following day.
Another way to display the diary entries for a date is to click
Mouse-2 on the date, and then choose Diary entries from
the menu that appears. If the variable
view-diary-entries-initially is non-nil, creating the
calendar also lists diary entries for the current date (provided the
current date is visible).
To get a broader view of which days are mentioned in the diary, use
the m command. This displays the dates that have diary entries in
a different face (or places a ‘+’ after these dates, if display
with multiple faces is not available). see diary-entry-marker. The command applies both to the
currently visible months and to other months that subsequently become
visible by scrolling. To turn marking off and erase the current marks,
type u, which also turns off holiday marks (see Holidays).
If the variable mark-diary-entries-in-calendar is
non-nil, creating or updating the calendar marks diary dates
automatically.
To see the full diary file, rather than just some of the entries, use the s command.
Display of selected diary entries uses the selective display feature
to hide entries that don't apply. The diary buffer as you see it is
an illusion, so simply printing the buffer does not print what you see
on your screen. There is a special command to print hard copy of the
diary buffer as it appears; this command is M-x
print-diary-entries. It sends the data directly to the printer. You
can customize it like lpr-region (see Printing).
The command M-x diary displays the diary entries for the current
date, independently of the calendar display, and optionally for the next
few days as well; the variable number-of-diary-entries specifies
how many days to include. see Diary Customizing.
If you put (diary) in your .emacs file, this
automatically displays a window with the day's diary entries, when you
enter Emacs. The mode line of the displayed window shows the date and
any holidays that fall on that date.
Many users like to receive notice of events in their diary as email.
To send such mail to yourself, use the command M-x
diary-mail-entries. A prefix argument specifies how many days
(starting with today) to check; otherwise, the variable
diary-mail-days says how many days.
Your diary file is a file that records events associated with
particular dates. The name of the diary file is specified by the
variable diary-file; ~/diary is the default. The
calendar utility program supports a subset of the format allowed
by the Emacs diary facilities, so you can use that utility to view the
diary file, with reasonable results aside from the entries it cannot
understand.
Each entry in the diary file describes one event and consists of one or more lines. An entry always begins with a date specification at the left margin. The rest of the entry is simply text to describe the event. If the entry has more than one line, then the lines after the first must begin with whitespace to indicate they continue a previous entry. Lines that do not begin with valid dates and do not continue a preceding entry are ignored.
You can inhibit the marking of certain diary entries in the calendar window; to do this, insert an ampersand (‘&’) at the beginning of the entry, before the date. This has no effect on display of the entry in the diary window; it affects only marks on dates in the calendar window. Nonmarking entries are especially useful for generic entries that would otherwise mark many different dates.
If the first line of a diary entry consists only of the date or day name with no following blanks or punctuation, then the diary window display doesn't include that line; only the continuation lines appear. For example, this entry:
02/11/1989
Bill B. visits Princeton today
2pm Cognitive Studies Committee meeting
2:30-5:30 Liz at Lawrenceville
4:00pm Dentist appt
7:30pm Dinner at George's
8:00-10:00pm concert
appears in the diary window without the date line at the beginning. This style of entry looks neater when you display just a single day's entries, but can cause confusion if you ask for more than one day's entries.
You can edit the diary entries as they appear in the window, but it is
important to remember that the buffer displayed contains the entire
diary file, with portions of it concealed from view. This means, for
instance, that the C-f (forward-char) command can put point
at what appears to be the end of the line, but what is in reality the
middle of some concealed line.
Be careful when editing the diary entries! Inserting
additional lines or adding/deleting characters in the middle of a
visible line cannot cause problems, but editing at the end of a line may
not do what you expect. Deleting a line may delete other invisible
entries that follow it. Before editing the diary, it is best to display
the entire file with s (show-all-diary-entries).
Here are some sample diary entries, illustrating different ways of formatting a date. The examples all show dates in American order (month, day, year), but Calendar mode supports European order (day, month, year) as an option.
4/20/93 Switch-over to new tabulation system
apr. 25 Start tabulating annual results
4/30 Results for April are due
*/25 Monthly cycle finishes
Friday Don't leave without backing up files
The first entry appears only once, on April 20, 1993. The second and third appear every year on the specified dates, and the fourth uses a wildcard (asterisk) for the month, so it appears on the 25th of every month. The final entry appears every week on Friday.
You can use just numbers to express a date, as in ‘month/day’ or ‘month/day/year’. This must be followed by a nondigit. In the date itself, month and day are numbers of one or two digits. The optional year is also a number, and may be abbreviated to the last two digits; that is, you can use ‘11/12/1989’ or ‘11/12/89’.
Dates can also have the form ‘monthname day’ or
‘monthname day, year’, where the month's name can
be spelled in full or abbreviated (with or without a period). The
preferred abbreviations can be controlled using the variables
calendar-abbrev-length, calendar-month-abbrev-array, and
calendar-day-abbrev-array. The default is to use the first three
letters of a name as its abbreviation. Case is not significant.
A date may be generic; that is, partially unspecified. Then the entry applies to all dates that match the specification. If the date does not contain a year, it is generic and applies to any year. Alternatively, month, day, or year can be a ‘*’; this matches any month, day, or year, respectively. Thus, a diary entry ‘3/*/*’ matches any day in March of any year; so does ‘march *’.
If you prefer the European style of writing dates—in which the day
comes before the month—type M-x european-calendar while in the
calendar, or set the variable european-calendar-style to t
before using any calendar or diary command. This mode interprets
all dates in the diary in the European manner, and also uses European
style for displaying diary dates. (Note that there is no comma after
the monthname in the European style.) To go back to the (default)
American style of writing dates, type M-x american-calendar.
You can use the name of a day of the week as a generic date which applies to any date falling on that day of the week. You can abbreviate the day of the week to three letters (with or without a period) or spell it in full; case is not significant.
While in the calendar, there are several commands to create diary entries:
insert-diary-entry).
insert-weekly-diary-entry).
insert-monthly-diary-entry).
insert-yearly-diary-entry).
You can make a diary entry for a specific date by selecting that date in the calendar window and typing the i d command. This command displays the end of your diary file in another window and inserts the date; you can then type the rest of the diary entry.
If you want to make a diary entry that applies to a specific day of the week, select that day of the week (any occurrence will do) and type i w. This inserts the day-of-week as a generic date; you can then type the rest of the diary entry. You can make a monthly diary entry in the same fashion: select the day of the month, use the i m command, and type the rest of the entry. Similarly, you can insert a yearly diary entry with the i y command.
All of the above commands make marking diary entries by default. To make a nonmarking diary entry, give a numeric argument to the command. For example, C-u i w makes a nonmarking weekly diary entry.
When you modify the diary file, be sure to save the file before
exiting Emacs. Saving the diary file after using any of the above
insertion commands will automatically update the diary marks in the
calendar window, if appropriate. You can use the command
redraw-calendar to force an update at any time.
In addition to entries based on calendar dates, the diary file can contain sexp entries for regular events such as anniversaries. These entries are based on Lisp expressions (sexps) that Emacs evaluates as it scans the diary file. Instead of a date, a sexp entry contains ‘%%’ followed by a Lisp expression which must begin and end with parentheses. The Lisp expression determines which dates the entry applies to.
Calendar mode provides commands to insert certain commonly used sexp entries:
insert-anniversary-diary-entry).
insert-block-diary-entry).
insert-cyclic-diary-entry).
If you want to make a diary entry that applies to the anniversary of a specific date, move point to that date and use the i a command. This displays the end of your diary file in another window and inserts the anniversary description; you can then type the rest of the diary entry. The entry looks like this:
%%(diary-anniversary 10 31 1948) Arthur's birthday
This entry applies to October 31 in any year after 1948; ‘10 31 1948’ specifies the date. (If you are using the European calendar style, the month and day are interchanged.) The reason this expression requires a beginning year is that advanced diary functions can use it to calculate the number of elapsed years.
A block diary entry applies to a specified range of consecutive dates. Here is a block diary entry that applies to all dates from June 24, 1990 through July 10, 1990:
%%(diary-block 6 24 1990 7 10 1990) Vacation
The ‘6 24 1990’ indicates the starting date and the ‘7 10 1990’ indicates the stopping date. (Again, if you are using the European calendar style, the month and day are interchanged.)
To insert a block entry, place point and the mark on the two dates that begin and end the range, and type i b. This command displays the end of your diary file in another window and inserts the block description; you can then type the diary entry.
Cyclic diary entries repeat after a fixed interval of days. To create one, select the starting date and use the i c command. The command prompts for the length of interval, then inserts the entry, which looks like this:
%%(diary-cyclic 50 3 1 1990) Renew medication
This entry applies to March 1, 1990 and every 50th day following; ‘3 1 1990’ specifies the starting date. (If you are using the European calendar style, the month and day are interchanged.)
All three of these commands make marking diary entries. To insert a nonmarking entry, give a numeric argument to the command. For example, C-u i a makes a nonmarking anniversary diary entry.
Marking sexp diary entries in the calendar is extremely time-consuming, since every date visible in the calendar window must be individually checked. So it's a good idea to make sexp diary entries nonmarking (with ‘&’) when possible.
Another sophisticated kind of sexp entry, a floating diary entry,
specifies a regularly occurring event by offsets specified in days,
weeks, and months. It is comparable to a crontab entry interpreted by
the cron utility. Here is a nonmarking, floating diary entry
that applies to the last Thursday in November:
&%%(diary-float 11 4 -1) American Thanksgiving
The 11 specifies November (the eleventh month), the 4 specifies Thursday
(the fourth day of the week, where Sunday is numbered zero), and the
−1 specifies “last” (1 would mean “first,” 2 would mean
“second,” −2 would mean “second-to-last,” and so on). The
month can be a single month or a list of months. Thus you could change
the 11 above to ‘'(1 2 3)’ and have the entry apply to the last
Thursday of January, February, and March. If the month is t, the
entry applies to all months of the year.
Each of the standard sexp diary entries takes an optional parameter specifying the name of a face or a single-character string to use when marking the entry in the calendar. Most generally, sexp diary entries can perform arbitrary computations to determine when they apply. see Sexp Diary Entries.
If you have a diary entry for an appointment, and that diary entry
begins with a recognizable time of day, Emacs can warn you several
minutes beforehand that that appointment is pending. Emacs alerts you
to the appointment by displaying a message in your chosen format, as
specified by the variable appt-display-format. If the value of
appt-audible is non-nil, an audible reminder is also
given. In addition, if appt-display-mode-line is non-nil,
Emacs displays the number of minutes to the appointment on the mode
line.
If appt-display-format has the value window, then the
variable appt-display-duration controls how long the reminder
window is visible for; and the variables
appt-disp-window-function and appt-delete-window-function
give the names of functions used to create and destroy the window,
respectively.
To enable appointment notification, call the function
appt-activate with a positive argument. This sets up an
appointment list for today from the diary file, giving all diary entries
found with recognizable times of day, and reminds you just before each
of them. Calling appt-activate with a negative argument disables
the appointment package. With no argument, it toggles.
For example, suppose the diary file contains these lines:
Monday
9:30am Coffee break
12:00pm Lunch
Then on Mondays, you will be reminded at around 9:20am about your coffee
break and at around 11:50am about lunch. How many minutes in advance you
are first warned is determined by the value of
appt-message-warning-time.
You can write times in am/pm style (with ‘12:00am’ standing for midnight and ‘12:00pm’ standing for noon), or 24-hour European/military style. You need not be consistent; your diary file can have a mixture of the two styles. Times must be at the beginning of lines if they are to be recognized.
Emacs updates the appointments list from the diary file automatically
just after midnight. An update can be forced at any time by
re-activating the appointment package. Both these actions also display
the day's diary buffer, unless you set appt-display-diary to
nil. The appointments list is also updated whenever the
diary file is saved.
You can also use the appointment notification facility like an alarm clock. The command M-x appt-add adds entries to the appointment list without affecting your diary file. You delete entries from the appointment list with M-x appt-delete.
You can transfer diary entries between Emacs diary files and a variety of other formats.
You can import diary entries from Outlook-generated appointment
messages. While viewing such a message in Rmail or Gnus, do M-x
diary-from-outlook to import the entry. You can make this command
recognize additional appointment message formats by customizing the
variable diary-outlook-formats.
The icalendar package allows you to transfer data between your Emacs diary file and iCalendar files, which are defined in “RFC 2445—Internet Calendaring and Scheduling Core Object Specification (iCalendar)” (as well as the earlier vCalendar format).
Importing works for “ordinary” (i.e. non-recurring) events, but (at present) may not work correctly (if at all) for recurring events. Exporting of diary files into iCalendar files should work correctly for most diary entries. Please note that icalendar.el is work in progress, so usage may evolve in future.
The command icalendar-import-buffer extracts
iCalendar data from the current buffer and adds it to your (default)
diary file. This function is also suitable for automatic extraction of
iCalendar data; for example with the Rmail mail client one could use:
(add-hook 'rmail-show-message-hook 'icalendar-import-buffer)
The command icalendar-import-file imports an iCalendar file
and adds the results to an Emacs diary file. For example:
(icalendar-import-file "/here/is/calendar.ics" "/there/goes/ical-diary")
You can use an #include directive to add the import file contents
to the main diary file, if these are distinct. see Fancy Diary Display.
Use icalendar-export-file to interactively export an entire
Emacs diary file to iCalendar format. To export only a part of a diary
file, mark the relevant area, and call icalendar-export-region.
In both cases the result is appended to the target file.
Emacs understands the difference between standard time and daylight savings time—the times given for sunrise, sunset, solstices, equinoxes, and the phases of the moon take that into account. The rules for daylight savings time vary from place to place and have also varied historically from year to year. To do the job properly, Emacs needs to know which rules to use.
Some operating systems keep track of the rules that apply to the place
where you are; on these systems, Emacs gets the information it needs
from the system automatically. If some or all of this information is
missing, Emacs fills in the gaps with the rules currently used in
Cambridge, Massachusetts. If the resulting rules are not what you want,
you can tell Emacs the rules to use by setting certain variables:
calendar-daylight-savings-starts and
calendar-daylight-savings-ends.
These values should be Lisp expressions that refer to the variable
year, and evaluate to the Gregorian date on which daylight
savings time starts or (respectively) ends, in the form of a list
(month day year). The values should be
nil if your area does not use daylight savings time.
Emacs uses these expressions to determine the starting date of daylight savings time for the holiday list and for correcting times of day in the solar and lunar calculations.
The values for Cambridge, Massachusetts are as follows:
(calendar-nth-named-day 1 0 4 year)
(calendar-nth-named-day -1 0 10 year)
That is, the first 0th day (Sunday) of the fourth month (April) in
the year specified by year, and the last Sunday of the tenth month
(October) of that year. If daylight savings time were
changed to start on October 1, you would set
calendar-daylight-savings-starts to this:
(list 10 1 year)
If there is no daylight savings time at your location, or if you want
all times in standard time, set calendar-daylight-savings-starts
and calendar-daylight-savings-ends to nil.
The variable calendar-daylight-time-offset specifies the
difference between daylight savings time and standard time, measured in
minutes. The value for Cambridge, Massachusetts is 60.
The two variables calendar-daylight-savings-starts-time and
calendar-daylight-savings-ends-time specify the number of minutes
after midnight local time when the transition to and from daylight
savings time should occur. For Cambridge, Massachusetts both variables'
values are 120.
The timeclock feature adds up time intervals, so you can (for instance) keep track of how much time you spend working.
Use the M-x timeclock-in command when you start working on a project, and M-x timeclock-out command when you're done. Each time you do this, it adds one time interval to the record of the project. You can change to working on a different project with M-x timeclock-change.
Once you've collected data from a number of time intervals, you can use M-x timeclock-workday-remaining to see how much time is left to work today (assuming a typical average of 8 hours a day), and M-x timeclock-when-to-leave which will calculate when you're “done.”
If you want Emacs to display the amount of time “left” of your
workday in the mode line, either customize the
timeclock-modeline-display variable and set its value to
t, or invoke the M-x timeclock-modeline-display command.
Terminating the current Emacs session might or might not mean that you
have stopped working on the project and, by default, Emacs queries this.
You can, however, set the value of the variable
timeclock-ask-before-exiting to nil (via M-x
customize) to avoid this behavior; then, only an explicit M-x
timeclock-out or M-x timeclock-change will tell Emacs that the
current interval is over.
The timeclock functions work by accumulating the data in a file
called .timelog in your home directory. You can specify a
different name for this file by customizing the variable
timeclock-file. If you edit the timeclock file manually, or if
you change the value of any of timeclock's customizable variables, you
should run the command M-x timeclock-reread-log to update the
data in Emacs from the file.
Gnus is an Emacs package primarily designed for reading and posting Usenet news. It can also be used to read and respond to messages from a number of other sources—mail, remote directories, digests, and so on.
Here we introduce Gnus and describe several basic features.
To start Gnus, type M-x gnus <RET>.
As opposed to most normal Emacs packages, Gnus uses a number of different buffers to display information and to receive commands. The three buffers users spend most of their time in are the group buffer, the summary buffer and the article buffer.
The group buffer contains a list of groups. This is the first buffer Gnus displays when it starts up. It normally displays only the groups to which you subscribe and that contain unread articles. Use this buffer to select a specific group.
The summary buffer lists one line for each article in a single group. By default, the author, the subject and the line number are displayed for each article, but this is customizable, like most aspects of Gnus display. The summary buffer is created when you select a group in the group buffer, and is killed when you exit the group. Use this buffer to select an article.
The article buffer displays the article. In normal Gnus usage, you don't select this buffer—all useful article-oriented commands work in the summary buffer. But you can select the article buffer, and execute all Gnus commands from that buffer, if you want to.
At startup, Gnus reads your .newsrc news initialization file and attempts to communicate with the local news server, which is a repository of news articles. The news server need not be the same computer you are logged in on.
If you start Gnus and connect to the server, but do not see any newsgroups listed in the group buffer, type L or A k to get a listing of all the groups. Then type u to toggle subscription to groups.
The first time you start Gnus, Gnus subscribes you to a few selected groups. All other groups start out as killed groups for you; you can list them with A k. All new groups that subsequently come to exist at the news server become zombie groups for you; type A z to list them. You can subscribe to a group shown in these lists using the u command.
When you quit Gnus with q, it automatically records in your .newsrc and .newsrc.eld initialization files the subscribed or unsubscribed status of all groups. You should normally not edit these files manually, but you may if you know how.
Reading news is a two-step process:
Each Gnus buffer has its own special commands; however, the meanings of any given key in the various Gnus buffers are usually analogous, even if not identical. Here are commands for the group and summary buffers:
In the summary buffer, exit the current group and return to the group buffer. Thus, typing q twice quits Gnus.
When you quit Gnus by typing q, Gnus writes information in the file .newsrc describing all newsgroups except those you have “killed.”
In the summary buffer,
Thus, you can move through all the articles by repeatedly typing <SPC>.
In the summary buffer, scroll the text of the article backwards.
Emacs has commands for passing single command lines to inferior shell processes; it can also run a shell interactively with input and output to an Emacs buffer named ‘*shell*’ or run a shell inside a terminal emulator window.
There is a shell implemented entirely in Emacs, documented in a separate manual. See Eshell.
shell-command).
shell-command-on-region).
M-! (shell-command) reads a line of text using the
minibuffer and executes it as a shell command in a subshell made just
for that command. Standard input for the command comes from the null
device. If the shell command produces any output, the output appears
either in the echo area (if it is short), or in an Emacs buffer named
‘*Shell Command Output*’, which is displayed in another window
but not selected (if the output is long).
For instance, one way to decompress a file foo.gz from Emacs is to type M-! gunzip foo.gz <RET>. That shell command normally creates the file foo and produces no terminal output.
A numeric argument, as in M-1 M-!, says to insert terminal output into the current buffer instead of a separate buffer. It puts point before the output, and sets the mark after the output. For instance, M-1 M-! gunzip < foo.gz <RET> would insert the uncompressed equivalent of foo.gz into the current buffer.
If the shell command line ends in ‘&’, it runs asynchronously.
For a synchronous shell command, shell-command returns the
command's exit status (0 means success), when it is called from a Lisp
program. You do not get any status information for an asynchronous
command, since it hasn't finished yet.
M-| (shell-command-on-region) is like M-! but
passes the contents of the region as the standard input to the shell
command, instead of no input. If a numeric argument is used, meaning
insert the output in the current buffer, then the old region is deleted
first and the output replaces it as the contents of the region. It
returns the command's exit status when it is called from a Lisp program.
One use for M-| is to run gpg to see what keys are in
the buffer. For instance, if the buffer contains a GPG key, type
C-x h M-| gpg <RET> to feed the entire buffer contents
to the gpg program. That program will ignore everything except
the encoded keys, and will output a list of the keys it contains.
Both M-! and M-| use shell-file-name to specify the
shell to use. This variable is initialized based on your SHELL
environment variable when Emacs is started. If the file name does not
specify a directory, the directories in the list exec-path are
searched; this list is initialized based on the environment variable
PATH when Emacs is started. Your .emacs file can override
either or both of these default initializations.
Both M-! and M-| wait for the shell command to complete,
unless you end the command with ‘&’ to make it asynchronous. To
stop waiting, type C-g to quit; that terminates the shell
command with the signal SIGINT—the same signal that C-c
normally generates in the shell. Emacs waits until the command
actually terminates. If the shell command doesn't stop (because it
ignores the SIGINT signal), type C-g again; this sends
the command a SIGKILL signal which is impossible to ignore.
Asynchronous commands ending in ‘&’ feed their output into the buffer ‘*Async Shell Command*’. Output arrives in that buffer regardless of whether it is visible in a window.
To specify a coding system for M-! or M-|, use the command C-x <RET> c immediately beforehand. See Specify Coding.
Error output from the command is normally intermixed with the regular
output. If you set the variable
shell-command-default-error-buffer to a string, which is a buffer
name, error output is inserted before point in the buffer of that name.
To run a subshell interactively, putting its typescript in an Emacs buffer, use M-x shell. This creates (or reuses) a buffer named ‘*shell*’ and runs a subshell with input coming from and output going to that buffer. That is to say, any “terminal output” from the subshell goes into the buffer, advancing point, and any “terminal input” for the subshell comes from text in the buffer. To give input to the subshell, go to the end of the buffer and type the input, terminated by <RET>.
Emacs does not wait for the subshell to do anything. You can switch windows or buffers and edit them while the shell is waiting, or while it is running a command. Output from the subshell waits until Emacs has time to process it; this happens whenever Emacs is waiting for keyboard input or for time to elapse.
Input lines, once you submit them, are displayed using the face
comint-highlight-input, and prompts are displayed using the
face comint-highlight-prompt. This makes it easier to see
previous input lines in the buffer. See Faces.
To make multiple subshells, you can invoke M-x shell with a prefix argument (e.g. C-u M-x shell), which will read a buffer name and create (or reuse) a subshell in that buffer. You can also rename the ‘*shell*’ buffer using M-x rename-uniquely, then create a new ‘*shell*’ buffer using plain M-x shell. All the subshells in different buffers run independently and in parallel.
The file name used to load the subshell is the value of the variable
explicit-shell-file-name, if that is non-nil. Otherwise,
the environment variable ESHELL is used, or the environment
variable SHELL if there is no ESHELL. If the file name
specified is relative, the directories in the list exec-path are
searched; this list is initialized based on the environment variable
PATH when Emacs is started. Your .emacs file can override
either or both of these default initializations.
Emacs sends the new shell the contents of the file ~/.emacs_shellname as input, if it exists, where shellname is the name of the file that the shell was loaded from. For example, if you use bash, the file sent to it is ~/.emacs_bash.
To specify a coding system for the shell, you can use the command C-x <RET> c immediately before M-x shell. You can also specify a coding system after starting the shell by using C-x <RET> p in the shell buffer. See Specify Coding.
Unless the environment variable EMACS is already defined,
Emacs defines it in the subshell, with value t. A shell script
can check this variable to determine whether it has been run from an
Emacs subshell.
Shell buffers use Shell mode, which defines several special keys attached to the C-c prefix. They are chosen to resemble the usual editing and job control characters present in shells that are not under Emacs, except that you must type C-c first. Here is a complete list of the special key bindings of Shell mode:
comint-send-input). When a line is
copied, any prompt at the beginning of the line (text output by
programs preceding your input) is omitted. See Shell Prompts, for
how Shell mode recognizes prompts.
comint-dynamic-complete). <TAB> also completes history
references (see History References) and environment variable names.
The variable shell-completion-fignore specifies a list of file
name extensions to ignore in Shell mode completion. The default
setting is nil, but some users prefer ("~" "#" "%") to
ignore file names ending in ‘~’, ‘#’ or ‘%’. Other
related Comint modes use the variable comint-completion-fignore
instead.
comint-dynamic-list-filename-completions).
comint-delchar-or-maybe-eof). Typed at the end of the shell
buffer, C-d sends EOF to the subshell. Typed at any other
position in the buffer, C-d deletes a character as usual.
comint-bol-or-process-mark). If you repeat this command twice
in a row, the second time it moves back to the process mark, which is
the beginning of the input that you have not yet sent to the subshell.
(Normally that is the same place—the end of the prompt on this
line—but after C-c <SPC> the process mark may be in a
previous line.)
comint-kill-input). If point is not at end of buffer,
this only kills the part of this text that precedes point.
backward-kill-word).
comint-interrupt-subjob). This command also kills
any shell input pending in the shell buffer and not yet sent.
comint-stop-subjob).
This command also kills any shell input pending in the shell buffer and
not yet sent.
comint-quit-subjob). This command also kills any shell input
pending in the shell buffer and not yet sent.
comint-delete-output). This is useful if a shell command spews
out lots of output that just gets in the way. This command used to be
called comint-kill-output.
comint-write-output). With a prefix argument, the file is
appended to instead. Any prompt at the end of the output is not
written.
comint-show-output).
comint-show-maximum-output).
shell-forward-command). The variable shell-command-regexp
specifies how to recognize the end of a command.
shell-backward-command).
Please note that Emacs will not echo passwords by default. If you really want them to be echoed, evaluate the following Lisp expression:
(remove-hook 'comint-output-filter-functions
'comint-watch-for-password-prompt)
(add-hook 'comint-output-filter-functions
'comint-strip-ctrl-m)
comint-buffer-maximum-size.
Here's how to do this automatically each time you get output from the
subshell:
(add-hook 'comint-output-filter-functions
'comint-truncate-buffer)
Shell mode is a derivative of Comint mode, a general-purpose mode for communicating with interactive subprocesses. Most of the features of Shell mode actually come from Comint mode, as you can see from the command names listed above. The special features of Shell mode include the directory tracking feature, and a few user commands.
Other Emacs features that use variants of Comint mode include GUD (see Debuggers) and M-x run-lisp (see External Lisp).
You can use M-x comint-run to execute any program of your choice in a subprocess using unmodified Comint mode—without the specializations of Shell mode.
A prompt is text output by a program to show that it is ready to
accept new user input. Normally, Comint mode (and thus Shell mode)
considers the prompt to be any text output by a program at the
beginning of an input line. However, if the variable
comint-use-prompt-regexp is non-nil, then Comint mode
uses a regular expression to recognize prompts. In Shell mode,
shell-prompt-pattern specifies the regular expression.
The value of comint-use-prompt-regexp also affects many
motion and paragraph commands. If the value is non-nil, the
general Emacs motion commands behave as they normally do in buffers
without special text properties. However, if the value is nil,
the default, then Comint mode divides the buffer into two types of
“fields” (ranges of consecutive characters having the same
field text property): input and output. Prompts are part of
the output. Most Emacs motion commands do not cross field boundaries,
unless they move over multiple lines. For instance, when point is in
input on the same line as a prompt, C-a puts point at the
beginning of the input if comint-use-prompt-regexp is
nil and at the beginning of the line otherwise.
In Shell mode, only shell prompts start new paragraphs. Thus, a
paragraph consists of a prompt and the input and output that follow
it. However, if comint-use-prompt-regexp is nil, the
default, most paragraph commands do not cross field boundaries. This
means that prompts, ranges of input, and ranges of non-prompt output
behave mostly like separate paragraphs; with this setting, numeric
arguments to most paragraph commands yield essentially undefined
behavior. For the purpose of finding paragraph boundaries, Shell mode
uses shell-prompt-pattern, regardless of
comint-use-prompt-regexp.
Shell buffers support three ways of repeating earlier commands. You can use keys like those used for the minibuffer history; these work much as they do in the minibuffer, inserting text from prior commands while point remains always at the end of the buffer. You can move through the buffer to previous inputs in their original place, then resubmit them or copy them to the end. Or you can use a ‘!’-style history reference.
comint-dynamic-list-input-ring).
Shell buffers provide a history of previously entered shell commands. To reuse shell commands from the history, use the editing commands M-p, M-n, M-r and M-s. These work just like the minibuffer history commands except that they operate on the text at the end of the shell buffer, where you would normally insert text to send to the shell.
M-p fetches an earlier shell command to the end of the shell buffer. Successive use of M-p fetches successively earlier shell commands, each replacing any text that was already present as potential shell input. M-n does likewise except that it finds successively more recent shell commands from the buffer. C-<UP> works like M-p, and C-<DOWN> like M-n.
The history search commands M-r and M-s read a regular expression and search through the history for a matching command. Aside from the choice of which command to fetch, they work just like M-p and M-n. If you enter an empty regexp, these commands reuse the same regexp used last time.
When you find the previous input you want, you can resubmit it by typing <RET>, or you can edit it first and then resubmit it if you wish.
Often it is useful to reexecute several successive shell commands that were previously executed in sequence. To do this, first find and reexecute the first command of the sequence. Then type C-c C-x; that will fetch the following command—the one that follows the command you just repeated. Then type <RET> to reexecute this command. You can reexecute several successive commands by typing C-c C-x <RET> over and over.
The command C-c . (comint-input-previous-argument)
copies an individual argument from a previous command, like ESC
. in Bash. The simplest use copies the last argument from the
previous shell command. With a prefix argument n, it copies the
nth argument instead. Repeating C-c . copies from an
earlier shell command instead, always using the same value of n
(don't give a prefix argument when you repeat the C-c .
command).
These commands get the text of previous shell commands from a special history list, not from the shell buffer itself. Thus, editing the shell buffer, or even killing large parts of it, does not affect the history that these commands access.
Some shells store their command histories in files so that you can refer to commands from previous shell sessions. Emacs reads the command history file for your chosen shell, to initialize its own command history. The file name is ~/.bash_history for bash, ~/.sh_history for ksh, and ~/.history for other shells.
comint-previous-prompt).
comint-next-prompt).
comint-insert-input). This is useful if you
move point back to a previous command. After you copy the command, you
can submit the copy as input with <RET>. If you wish, you can
edit the copy before resubmitting it.
Moving to a previous input and then copying it with C-c <RET> or Mouse-2 produces the same results—the same buffer contents—that you would get by using M-p enough times to fetch that previous input from the history list. However, C-c <RET> copies the text from the buffer, which can be different from what is in the history list if you edit the input text in the buffer after it has been sent.
Various shells including csh and bash support history references that begin with ‘!’ and ‘^’. Shell mode recognizes these constructs, and can perform the history substitution for you.
If you insert a history reference and type <TAB>, this searches the input history for a matching command, performs substitution if necessary, and places the result in the buffer in place of the history reference. For example, you can fetch the most recent command beginning with ‘mv’ with ! m v <TAB>. You can edit the command if you wish, and then resubmit the command to the shell by typing <RET>.
Shell mode can optionally expand history references in the buffer
when you send them to the shell. To request this, set the variable
comint-input-autoexpand to input. You can make
<SPC> perform history expansion by binding <SPC> to the
command comint-magic-space.
Shell mode recognizes history references when they follow a prompt. See Shell Prompts, for how Shell mode recognizes prompts.
Shell mode keeps track of ‘cd’, ‘pushd’ and ‘popd’ commands given to the inferior shell, so it can keep the ‘*shell*’ buffer's default directory the same as the shell's working directory. It recognizes these commands syntactically, by examining lines of input that are sent.
If you use aliases for these commands, you can tell Emacs to
recognize them also. For example, if the value of the variable
shell-pushd-regexp matches the beginning of a shell command
line, that line is regarded as a pushd command. Change this
variable when you add aliases for ‘pushd’. Likewise,
shell-popd-regexp and shell-cd-regexp are used to
recognize commands with the meaning of ‘popd’ and ‘cd’.
These commands are recognized only at the beginning of a shell command
line.
If Emacs gets confused about changes in the current directory of the subshell, use the command M-x dirs to ask the shell what its current directory is. This command works for shells that support the most common command syntax; it may not work for unusual shells.
You can also use M-x dirtrack-mode to enable (or disable) an alternative and more aggressive method of tracking changes in the current directory.
If the variable comint-scroll-to-bottom-on-input is
non-nil, insertion and yank commands scroll the selected window
to the bottom before inserting.
If comint-scroll-show-maximum-output is non-nil, then
arrival of output when point is at the end tries to place the last line of
text at the bottom line of the window, so as to show as much useful
text as possible. (This mimics the scrolling behavior of many
terminals.) The default is nil.
By setting comint-move-point-for-output, you can opt for
having point jump to the end of the buffer whenever output arrives—no
matter where in the buffer point was before. If the value is
this, point jumps in the selected window. If the value is
all, point jumps in each window that shows the Comint buffer. If
the value is other, point jumps in all nonselected windows that
show the current buffer. The default value is nil, which means
point does not jump to the end.
If you set comint-prompt-read-only, the prompts in the Comint
buffer are read-only.
The variable comint-input-ignoredups controls whether successive
identical inputs are stored in the input history. A non-nil
value means to omit an input that is the same as the previous input.
The default is nil, which means to store each input even if it is
equal to the previous input.
Three variables customize file name completion. The variable
comint-completion-addsuffix controls whether completion inserts a
space or a slash to indicate a fully completed file or directory name
(non-nil means do insert a space or slash).
comint-completion-recexact, if non-nil, directs <TAB>
to choose the shortest possible completion if the usual Emacs completion
algorithm cannot add even a single character.
comint-completion-autolist, if non-nil, says to list all
the possible completions whenever completion is not exact.
Command completion normally considers only executable files.
If you set shell-completion-execonly to nil,
it considers nonexecutable files as well.
You can configure the behavior of ‘pushd’. Variables control
whether ‘pushd’ behaves like ‘cd’ if no argument is given
(shell-pushd-tohome), pop rather than rotate with a numeric
argument (shell-pushd-dextract), and only add directories to the
directory stack if they are not already on it
(shell-pushd-dunique). The values you choose should match the
underlying shell, of course.
If you want Shell mode to handle color output from shell commands, you can enable ANSI Color mode. Here is how to do this:
(add-hook 'shell-mode-hook 'ansi-color-for-comint-mode-on)
To run a subshell in a terminal emulator, putting its typescript in an Emacs buffer, use M-x term. This creates (or reuses) a buffer named ‘*terminal*’, and runs a subshell with input coming from your keyboard, and output going to that buffer.
The terminal emulator uses Term mode, which has two input modes. In line mode, Term basically acts like Shell mode; see Shell Mode.
In char mode, each character is sent directly to the inferior subshell, as “terminal input.” Any “echoing” of your input is the responsibility of the subshell. The sole exception is the terminal escape character, which by default is C-c (see Term Mode). Any “terminal output” from the subshell goes into the buffer, advancing point.
Some programs (such as Emacs itself) need to control the appearance
on the terminal screen in detail. They do this by sending special
control codes. The exact control codes needed vary from terminal to
terminal, but nowadays most terminals and terminal emulators
(including xterm) understand the ANSI-standard (VT100-style)
escape sequences. Term mode recognizes these escape sequences, and
handles each one appropriately, changing the buffer so that the
appearance of the window matches what it would be on a real terminal.
You can actually run Emacs inside an Emacs Term window.
The file name used to load the subshell is determined the same way as for Shell mode. To make multiple terminal emulators, rename the buffer ‘*terminal*’ to something different using M-x rename-uniquely, just as with Shell mode.
Unlike Shell mode, Term mode does not track the current directory by
examining your input. But some shells can tell Term what the current
directory is. This is done automatically by bash version 1.15
and later.
The terminal emulator uses Term mode, which has two input modes. In line mode, Term basically acts like Shell mode; see Shell Mode. In char mode, each character is sent directly to the inferior subshell, except for the Term escape character, normally C-c.
To switch between line and char mode, use these commands:
The following commands are only available in char mode:
Term mode has a page-at-a-time feature. When enabled it makes output pause at the end of each screenful.
With page-at-a-time enabled, whenever Term receives more than a
screenful of output since your last input, it pauses, displaying
‘**MORE**’ in the mode-line. Type <SPC> to display the next
screenful of output. Type ? to see your other options. The
interface is similar to the more program.
You can login to a remote computer, using whatever commands you
would from a regular terminal (e.g. using the telnet or
rlogin commands), from a Term window.
A program that asks you for a password will normally suppress echoing of the password, so the password will not show up in the buffer. This will happen just as if you were using a real terminal, if the buffer is in char mode. If it is in line mode, the password is temporarily visible, but will be erased when you hit return. (This happens automatically; there is no special password processing.)
When you log in to a different machine, you need to specify the type of terminal you're using, by setting the TERM environment variable in the environment for the remote login command. (If you use bash, you do that by writing the variable assignment before the remote login command, without separating comma.) Terminal types ‘ansi’ or ‘vt100’ will work on most systems.
Various programs such as mail can invoke your choice of editor
to edit a particular piece of text, such as a message that you are
sending. By convention, most of these programs use the environment
variable EDITOR to specify which editor to run. If you set
EDITOR to ‘emacs’, they invoke Emacs—but in an
inconvenient fashion, by starting a new, separate Emacs process. This
is inconvenient because it takes time and because the new Emacs process
doesn't share the buffers in any existing Emacs process.
You can arrange to use your existing Emacs process as the editor for
programs like mail by using the Emacs client and Emacs server
programs. Here is how.
First, the preparation. Within Emacs, call the function
server-start. (Your .emacs file can do this automatically
if you add the expression (server-start) to it.) Then, outside
Emacs, set the EDITOR environment variable to ‘emacsclient’.
(Note that some programs use a different environment variable; for
example, to make TeX use ‘emacsclient’, you should set the
TEXEDIT environment variable to ‘emacsclient +%d %s’.)
Then, whenever any program invokes your specified EDITOR
program, the effect is to send a message to your principal Emacs telling
it to visit a file. (That's what the program emacsclient does.)
Emacs displays the buffer immediately and you can immediately begin
editing it.
When you've finished editing that buffer, type C-x #
(server-edit). This saves the file and sends a message back to
the emacsclient program telling it to exit. The programs that
use EDITOR wait for the “editor” (actually, emacsclient)
to exit. C-x # also checks for other pending external requests
to edit various files, and selects the next such file.
You can switch to a server buffer manually if you wish; you don't have to arrive at it with C-x #. But C-x # is the way to say that you are finished with one.
Finishing with a server buffer also kills the buffer, unless it
already existed in the Emacs session before the server asked to create
it. However, if you set server-kill-new-buffers to nil,
then a different criterion is used: finishing with a server buffer
kills it if the file name matches the regular expression
server-temp-file-regexp. This is set up to distinguish certain
“temporary” files.
If you set the variable server-window to a window or a frame,
C-x # displays the server buffer in that window or in that frame.
You can run multiple Emacs servers on the same machine by giving
each one a unique “server name”, using the variable
server-name. For example, M-x set-variable <RET>
server-name <RET> foo <RET> sets the server name to
‘foo’. The emacsclient program can visit a server by name
using the ‘-s’ option. See Invoking emacsclient.
While mail or another application is waiting for
emacsclient to finish, emacsclient does not read terminal
input. So the terminal that mail was using is effectively
blocked for the duration. In order to edit with your principal Emacs,
you need to be able to use it without using that terminal. There are
three ways to do this:
mail and the principal Emacs in two
separate windows. While mail is waiting for emacsclient,
the window where it was running is blocked, but you can use Emacs by
switching windows.
mail in one virtual terminal
and run Emacs in another.
mail; then, emacsclient blocks only the subshell under
Emacs, and you can still use Emacs to edit the file.
If you run emacsclient with the option ‘--no-wait’, it
returns immediately without waiting for you to “finish” the buffer
in Emacs. Note that server buffers created in this way are not killed
automatically when you finish with them.
emacsclientTo run the emacsclient program, specify file names as arguments,
and optionally line numbers as well. Do it like this:
emacsclient {[+line[column]] filename}...
This tells Emacs to visit each of the specified files; if you specify a line number for a certain file, Emacs moves to that line in the file. If you specify a column number as well, Emacs puts point on that column in the line.
Ordinarily, emacsclient does not return until you use the
C-x # command on each of these buffers. When that happens,
Emacs sends a message to the emacsclient program telling it to
return.
But if you use the option ‘-n’ or ‘--no-wait’ when running
emacsclient, then it returns immediately. (You can take as
long as you like to edit the files in Emacs.)
The option ‘--alternate-editor=command’ is useful when
running emacsclient in a script. It specifies a command to run
if emacsclient fails to contact Emacs. For example, the
following setting for the EDITOR environment variable will
always give you an editor, even if no Emacs server is running:
EDITOR="emacsclient --alternate-editor emacs +%d %s"
The environment variable ALTERNATE_EDITOR has the same effect, but the value of the ‘--alternate-editor’ takes precedence.
Alternatively, the file etc/emacs.bash defines a bash function which will communicate with a running Emacs server, or start one if none exists.
If you use several displays, you can tell Emacs on which display to open the given files with the option ‘--display=DISPLAY’. This can be used typically when connecting from home to an Emacs server running on your machine at your workplace.
If there is more than one Emacs server running, you can specify a server name with the option ‘-s name’.
You can also use emacsclient to execute any piece of Emacs Lisp
code, using the option ‘--eval’. When this option is given, the
rest of the arguments is not taken as a list of files to visit but as
a list of expressions to evaluate.
Emacs provides commands for printing hard copies of either an entire buffer or just part of one, with or without page headers. You can invoke the printing commands directly, as detailed in the following section, or using the ‘File’ menu on the menu bar. See also the hardcopy commands of Dired (see Misc File Ops) and the diary (see Displaying the Diary).
print-buffer but print only the current region.
lpr-buffer but print only the current region.
The hardcopy commands (aside from the Postscript commands) pass extra
switches to the lpr program based on the value of the variable
lpr-switches. Its value should be a list of strings, each string
an option starting with ‘-’. For example, to specify a line width
of 80 columns for all the printing you do in Emacs, set
lpr-switches like this:
(setq lpr-switches '("-w80"))
You can specify the printer to use by setting the variable
printer-name.
The variable lpr-command specifies the name of the printer
program to run; the default value depends on your operating system type.
On most systems, the default is "lpr". The variable
lpr-headers-switches similarly specifies the extra switches to
use to make page headers. The variable lpr-add-switches controls
whether to supply ‘-T’ and ‘-J’ options (suitable for
lpr) to the printer program: nil means don't add them.
lpr-add-switches should be nil if your printer program is
not compatible with lpr.
These commands convert buffer contents to PostScript, either printing it or leaving it in another Emacs buffer.
The PostScript commands, ps-print-buffer and
ps-print-region, print buffer contents in PostScript form. One
command prints the entire buffer; the other, just the region. The
corresponding ‘-with-faces’ commands,
ps-print-buffer-with-faces and ps-print-region-with-faces,
use PostScript features to show the faces (fonts and colors) in the text
properties of the text being printed.
If you are using a color display, you can print a buffer of program
code with color highlighting by turning on Font-Lock mode in that
buffer, and using ps-print-buffer-with-faces.
The commands whose names have ‘spool’ instead of ‘print’ generate the PostScript output in an Emacs buffer instead of sending it to the printer.
M-x handwrite is more frivolous. It generates a PostScript
rendition of the current buffer as a cursive handwritten document. It
can be customized in group handwrite. This function only
supports ISO 8859-1 characters.
All the PostScript hardcopy commands use the variables
ps-lpr-command and ps-lpr-switches to specify how to print
the output. ps-lpr-command specifies the command name to run,
ps-lpr-switches specifies command line options to use, and
ps-printer-name specifies the printer. If you don't set the
first two variables yourself, they take their initial values from
lpr-command and lpr-switches. If ps-printer-name
is nil, printer-name is used.
The variable ps-print-header controls whether these commands
add header lines to each page—set it to nil to turn headers
off.
If your printer doesn't support colors, you should turn off color
processing by setting ps-print-color-p to nil. By
default, if the display supports colors, Emacs produces hardcopy output
with color information; on black-and-white printers, colors are emulated
with shades of gray. This might produce illegible output, even if your
screen colors only use shades of gray.
By default, PostScript printing ignores the background colors of the
faces, unless the variable ps-use-face-background is
non-nil. This is to avoid unwanted interference with the zebra
stripes and background image/text.
The variable ps-paper-type specifies which size of paper to
format for; legitimate values include a4, a3,
a4small, b4, b5, executive, ledger,
legal, letter, letter-small, statement,
tabloid. The default is letter. You can define
additional paper sizes by changing the variable
ps-page-dimensions-database.
The variable ps-landscape-mode specifies the orientation of
printing on the page. The default is nil, which stands for
“portrait” mode. Any non-nil value specifies “landscape”
mode.
The variable ps-number-of-columns specifies the number of
columns; it takes effect in both landscape and portrait mode. The
default is 1.
The variable ps-font-family specifies which font family to use
for printing ordinary text. Legitimate values include Courier,
Helvetica, NewCenturySchlbk, Palatino and
Times. The variable ps-font-size specifies the size of
the font for ordinary text. It defaults to 8.5 points.
Emacs supports more scripts and characters than a typical PostScript
printer. Thus, some of the characters in your buffer might not be
printable using the fonts built into your printer. You can augment
the fonts supplied with the printer with those from the GNU Intlfonts
package, or you can instruct Emacs to use Intlfonts exclusively. The
variable ps-multibyte-buffer controls this: the default value,
nil, is appropriate for printing ASCII and Latin-1
characters; a value of non-latin-printer is for printers which
have the fonts for ASCII, Latin-1, Japanese, and Korean
characters built into them. A value of bdf-font arranges for
the BDF fonts from the Intlfonts package to be used for all
characters. Finally, a value of bdf-font-except-latin
instructs the printer to use built-in fonts for ASCII and Latin-1
characters, and Intlfonts BDF fonts for the rest.
To be able to use the BDF fonts, Emacs needs to know where to find
them. The variable bdf-directory-list holds the list of
directories where Emacs should look for the fonts; the default value
includes a single directory /usr/local/share/emacs/fonts/bdf.
Many other customization variables for these commands are defined and described in the Lisp files ps-print.el and ps-mule.el.
The basic Emacs facilities for printing hardcopy can be extended using the Printing package. This provides an easy-to-use interface for choosing what to print, previewing PostScript files before printing, and setting various printing options such as print headers, landscape or portrait modes, duplex modes, and so forth. On GNU/Linux or Unix systems, the Printing package relies on the gs and gv utilities, which are distributed as part of the GhostScript program. On MS-Windows, the gstools port of Ghostscript can be used.
To use the Printing package, add (require 'printing) to your
init file (see Init File), followed by (pr-update-menus).
This function replaces the usual printing commands in the menu bar
with a ‘Printing’ submenu that contains various printing options.
You can also type M-x pr-interface RET; this creates a
‘*Printing Interface*’ buffer, similar to a customization buffer,
where you can set the printing options. After selecting what and how
to print, you start the print job using the ‘Print’ button (click
mouse-2 on it, or move point over it and type RET). For
further information on the various options, use the ‘Interface
Help’ button.
Emacs provides several commands for sorting text in the buffer. All operate on the contents of the region. They divide the text of the region into many sort records, identify a sort key for each record, and then reorder the records into the order determined by the sort keys. The records are ordered so that their keys are in alphabetical order, or, for numeric sorting, in numeric order. In alphabetic sorting, all upper-case letters `A' through `Z' come before lower-case `a', in accord with the ASCII character sequence.
The various sort commands differ in how they divide the text into sort records and in which part of each record is used as the sort key. Most of the commands make each line a separate sort record, but some commands use paragraphs or pages as sort records. Most of the sort commands use each entire sort record as its own sort key, but some use only a portion of the record as the sort key.
Specify which field to sort by with a numeric argument: 1 to sort by
field 1, etc. A negative argument means count fields from the right
instead of from the left; thus, minus 1 means sort by the last field.
If several lines have identical contents in the field being sorted, they
keep the same relative order that they had in the original buffer.
sort-numeric-base, but numbers beginning with ‘0x’ or
‘0’ are interpreted as hexadecimal and octal, respectively.
For example, if the buffer contains this:
On systems where clash detection (locking of files being edited) is
implemented, Emacs also checks the first time you modify a buffer
whether the file has changed on disk since it was last visited or
saved. If it has, you are asked to confirm that you want to change
the buffer.
applying M-x sort-lines to the entire buffer produces this:
On systems where clash detection (locking of files being edited) is
implemented, Emacs also checks the first time you modify a buffer
saved. If it has, you are asked to confirm that you want to change
the buffer.
whether the file has changed on disk since it was last visited or
where the upper-case ‘O’ sorts before all lower-case letters. If you use C-u 2 M-x sort-fields instead, you get this:
implemented, Emacs also checks the first time you modify a buffer
saved. If it has, you are asked to confirm that you want to change
the buffer.
On systems where clash detection (locking of files being edited) is
whether the file has changed on disk since it was last visited or
where the sort keys were ‘Emacs’, ‘If’, ‘buffer’, ‘systems’ and ‘the’.
M-x sort-columns requires more explanation. You specify the columns by putting point at one of the columns and the mark at the other column. Because this means you cannot put point or the mark at the beginning of the first line of the text you want to sort, this command uses an unusual definition of “region”: all of the line point is in is considered part of the region, and so is all of the line the mark is in, as well as all the lines in between.
For example, to sort a table by information found in columns 10 to 15,
you could put the mark on column 10 in the first line of the table, and
point on column 15 in the last line of the table, and then run
sort-columns. Equivalently, you could run it with the mark on
column 15 in the first line and point on column 10 in the last line.
This can be thought of as sorting the rectangle specified by point and the mark, except that the text on each line to the left or right of the rectangle moves along with the text inside the rectangle. See Rectangles.
Many of the sort commands ignore case differences when comparing, if
sort-fold-case is non-nil.
Narrowing means focusing in on some portion of the buffer, making the rest temporarily inaccessible. The portion which you can still get to is called the accessible portion. Canceling the narrowing, which makes the entire buffer once again accessible, is called widening. The amount of narrowing in effect in a buffer at any time is called the buffer's restriction.
Narrowing can make it easier to concentrate on a single subroutine or paragraph by eliminating clutter. It can also be used to restrict the range of operation of a replace command or repeating keyboard macro.
narrow-to-region).
widen).
narrow-to-page).
narrow-to-defun).
When you have narrowed down to a part of the buffer, that part appears to be all there is. You can't see the rest, you can't move into it (motion commands won't go outside the accessible part), you can't change it in any way. However, it is not gone, and if you save the file all the inaccessible text will be saved. The word ‘Narrow’ appears in the mode line whenever narrowing is in effect.
The primary narrowing command is C-x n n (narrow-to-region).
It sets the current buffer's restrictions so that the text in the current
region remains accessible, but all text before the region or after the
region is inaccessible. Point and mark do not change.
Alternatively, use C-x n p (narrow-to-page) to narrow
down to the current page. See Pages, for the definition of a page.
C-x n d (narrow-to-defun) narrows down to the defun
containing point (see Defuns).
The way to cancel narrowing is to widen with C-x n w
(widen). This makes all text in the buffer accessible again.
You can get information on what part of the buffer you are narrowed down to using the C-x = command. See Position Info.
Because narrowing can easily confuse users who do not understand it,
narrow-to-region is normally a disabled command. Attempting to use
this command asks for confirmation and gives you the option of enabling it;
if you enable the command, confirmation will no longer be required for
it. See Disabling.
Two-column mode lets you conveniently edit two side-by-side columns of text. It uses two side-by-side windows, each showing its own buffer.
There are three ways to enter two-column mode:
2C-two-columns). If the right-hand buffer doesn't already
exist, it starts out empty; the current buffer's contents are not
changed.
This command is appropriate when the current buffer is empty or contains
just one column and you want to add another column.
2C-split). The current
buffer becomes the left-hand buffer, but the text in the right-hand
column is moved into the right-hand buffer. The current column
specifies the split point. Splitting starts with the current line and
continues to the end of the buffer.
This command is appropriate when you have a buffer that already contains
two-column text, and you wish to separate the columns temporarily.
2C-associate-buffer).
<F2> s or C-x 6 s looks for a column separator, which is a string that appears on each line between the two columns. You can specify the width of the separator with a numeric argument to <F2> s; that many characters, before point, constitute the separator string. By default, the width is 1, so the column separator is the character before point.
When a line has the separator at the proper place, <F2> s puts the text after the separator into the right-hand buffer, and deletes the separator. Lines that don't have the column separator at the proper place remain unsplit; they stay in the left-hand buffer, and the right-hand buffer gets an empty line to correspond. (This is the way to write a line that “spans both columns while in two-column mode”: write it in the left-hand buffer, and put an empty line in the right-hand buffer.)
The command C-x 6 <RET> or <F2> <RET>
(2C-newline) inserts a newline in each of the two buffers at
corresponding positions. This is the easiest way to add a new line to
the two-column text while editing it in split buffers.
When you have edited both buffers as you wish, merge them with
<F2> 1 or C-x 6 1 (2C-merge). This copies the
text from the right-hand buffer as a second column in the other buffer.
To go back to two-column editing, use <F2> s.
Use <F2> d or C-x 6 d to dissociate the two buffers,
leaving each as it stands (2C-dissociate). If the other buffer,
the one not current when you type <F2> d, is empty,
<F2> d kills it.
There is a special major mode for editing binary files: Hexl mode. To use it, use M-x hexl-find-file instead of C-x C-f to visit the file. This command converts the file's contents to hexadecimal and lets you edit the translation. When you save the file, it is converted automatically back to binary.
You can also use M-x hexl-mode to translate an existing buffer into hex. This is useful if you visit a file normally and then discover it is a binary file.
Ordinary text characters overwrite in Hexl mode. This is to reduce the risk of accidentally spoiling the alignment of data in the file. There are special commands for insertion. Here is a list of the commands of Hexl mode:
hexl-mode.
Other Hexl commands let you insert strings (sequences) of binary
bytes, move by shorts or ints, etc.; type C-h a
hexl-<RET> for details.
Use the desktop library to save the state of Emacs from one session to another. Once you save the Emacs desktop—the buffers, their file names, major modes, buffer positions, and so on—then subsequent Emacs sessions reload the saved desktop.
You can save the desktop manually with the command M-x
desktop-save. You can also enable automatic desktop saving when
you exit Emacs: use the Customization buffer (see Easy Customization) to set desktop-save-mode to t for future
sessions, or add this line in your ~/.emacs file:
(desktop-save-mode 1)
When Emacs starts, it looks for a saved desktop in the current directory. Thus, you can have separate saved desktops in different directories, and the starting directory determines which one Emacs reloads. You can save the current desktop and reload one saved in another directory by typing M-x desktop-change-dir. Typing M-x desktop-revert reverts to the desktop previously reloaded.
Specify the option ‘--no-desktop’ on the command line when you
don't want it to reload any saved desktop. This turns off
desktop-save-mode for the current session.
By default, all the buffers in the desktop are restored at one go.
However, this may be slow if there are a lot of buffers in the
desktop. You can specify the maximum number of buffers to restore
immediately with the variable desktop-restore-eager; the
remaining buffers are restored “lazily,” when Emacs is idle.
Type M-x desktop-clear to empty the Emacs desktop. This kills
all buffers except for internal ones, and clears the global variables
listed in desktop-globals-to-clear. If you want this to
preserve certain buffers, customize the variable
desktop-clear-preserve-buffers-regexp, whose value is a regular
expression matching the names of buffers not to kill.
If you want to save minibuffer history from one session to
another, use the savehist library.
A recursive edit is a situation in which you are using Emacs
commands to perform arbitrary editing while in the middle of another
Emacs command. For example, when you type C-r inside of a
query-replace, you enter a recursive edit in which you can change
the current buffer. On exiting from the recursive edit, you go back to
the query-replace.
Exiting the recursive edit means returning to the unfinished
command, which continues execution. The command to exit is C-M-c
(exit-recursive-edit).
You can also abort the recursive edit. This is like exiting,
but also quits the unfinished command immediately. Use the command
C-] (abort-recursive-edit) to do this. See Quitting.
The mode line shows you when you are in a recursive edit by displaying square brackets around the parentheses that always surround the major and minor mode names. Every window's mode line shows this in the same way, since being in a recursive edit is true of Emacs as a whole rather than any particular window or buffer.
It is possible to be in recursive edits within recursive edits. For
example, after typing C-r in a query-replace, you may type a
command that enters the debugger. This begins a recursive editing level
for the debugger, within the recursive editing level for C-r.
Mode lines display a pair of square brackets for each recursive editing
level currently in progress.
Exiting the inner recursive edit (such as with the debugger c command) resumes the command running in the next level up. When that command finishes, you can then use C-M-c to exit another recursive editing level, and so on. Exiting applies to the innermost level only. Aborting also gets out of only one level of recursive edit; it returns immediately to the command level of the previous recursive edit. If you wish, you can then abort the next recursive editing level.
Alternatively, the command M-x top-level aborts all levels of recursive edits, returning immediately to the top-level command reader.
The text being edited inside the recursive edit need not be the same text that you were editing at top level. It depends on what the recursive edit is for. If the command that invokes the recursive edit selects a different buffer first, that is the buffer you will edit recursively. In any case, you can switch buffers within the recursive edit in the normal manner (as long as the buffer-switching keys have not been rebound). You could probably do all the rest of your editing inside the recursive edit, visiting files and all. But this could have surprising effects (such as stack overflow) from time to time. So remember to exit or abort the recursive edit when you no longer need it.
In general, we try to minimize the use of recursive editing levels in GNU Emacs. This is because they constrain you to “go back” in a particular order—from the innermost level toward the top level. When possible, we present different activities in separate buffers so that you can switch between them as you please. Some commands switch to a new major mode which provides a command to switch back. These approaches give you more flexibility to go back to unfinished tasks in the order you choose.
GNU Emacs can be programmed to emulate (more or less) most other editors. Standard facilities can emulate these:
crisp-override-meta-x. You can
also use the command M-x scroll-all-mode or set the variable
crisp-load-scroll-all to emulate CRiSP's scroll-all feature
(scrolling all windows together).
Most of the EDT emulation commands are keypad keys, and most standard
Emacs key bindings are still available. The EDT emulation rebindings
are done in the global keymap, so there is no problem switching
buffers or major modes while in EDT emulation.
Because vi emulation works through major modes, it does not work to switch buffers during emulation. Return to normal Emacs first.
If you plan to use vi emulation much, you probably want to bind a key
to the vi-mode command.
This emulation does not work through major modes, and it is possible
to switch buffers in various ways within the emulator. It is not
so necessary to assign a key to the command vip-mode as
it is with vi-mode because terminating insert mode does
not use it.
see VIP, for full information.
Various modes documented elsewhere have hypertext features so that you can follow links, usually by clicking Mouse-2 on the link or typing <RET> while point is on the link. Clicking Mouse-1 quickly on the link also follows it. (Hold Mouse-1 for longer if you want to set point instead.)
Info mode, Help mode and the Dired-like modes are examples of modes that have links in the buffer. The Tags facility links between uses and definitions in source files, see Tags. Imenu provides navigation amongst items indexed in the current buffer, see Imenu. Info-lookup provides mode-specific lookup of definitions in Info indexes, see Documentation. Speedbar maintains a frame in which links to files, and locations in files are displayed, see Speedbar.
Other non-mode-specific facilities described in this section enable following links from the current buffer in a context-sensitive fashion.
The Browse-URL package provides facilities for following URLs specifying
links on the World Wide Web. Usually this works by invoking a web
browser, but you can, for instance, arrange to invoke compose-mail
from ‘mailto:’ URLs.
The general way to use this feature is to type M-x browse-url,
which displays a specified URL. If point is located near a plausible
URL, that URL is used as the default. Other commands are available
which you might like to bind to keys, such as
browse-url-at-point and browse-url-at-mouse.
You can customize Browse-URL's behavior via various options in the
browse-url Customize group, particularly
browse-url-browser-function. You can invoke actions dependent
on the type of URL by defining browse-url-browser-function as
an association list. The package's commentary available via C-h
p under the ‘hypermedia’ keyword provides more information.
Packages with facilities for following URLs should always go through
Browse-URL, so that the customization options for Browse-URL will
affect all browsing in Emacs.
You can make URLs in the current buffer active with M-x goto-address. This finds all the URLs in the buffer, and establishes bindings for Mouse-2 and C-c <RET> on them. After activation, if you click on a URL with Mouse-2, or move to a URL and type C-c <RET>, that will display the web page that the URL specifies. For a ‘mailto’ URL, it sends mail instead, using your selected mail-composition method (see Mail Methods).
It can be useful to add goto-address to mode hooks and the
hooks used to display an incoming message.
rmail-show-message-hook is the appropriate hook for Rmail, and
mh-show-mode-hook for MH-E. This is not needed for Gnus,
which has a similar feature of its own.
FFAP mode replaces certain key bindings for finding files, including
C-x C-f, with commands that provide more sensitive defaults.
These commands behave like the ordinary ones when given a prefix
argument. Otherwise, they get the default file name or URL from the
text around point. If what is found in the buffer has the form of a
URL rather than a file name, the commands use browse-url to
view it.
This feature is useful for following references in mail or news
buffers, README files, MANIFEST files, and so on. The
‘ffap’ package's commentary available via C-h p under the
‘files’ keyword and the ffap Custom group provide details.
You can turn on FFAP minor mode by calling ffap-bindings to
make the following key bindings and to install hooks for using
ffap in Rmail, Gnus and VM article buffers.
find-file-at-point).
ffap-read-only, analogous to find-file-read-only.
ffap-alternate-file, analogous to find-alternate-file.
dired-at-point).
ffap-list-directory, analogous to list-directory.
ffap-other-window, analogous to find-file-other-window.
ffap-read-only-other-window, analogous to
find-file-read-only-other-window.
ffap-dired-other-window, analogous to dired-other-window.
ffap-other-frame, analogous to find-file-other-frame.
ffap-read-only-other-frame, analogous to
find-file-read-only-other-frame.
ffap-dired-other-frame, analogous to dired-other-frame.
ffap-at-mouse finds the file guessed from text around the position
of a mouse click.
ffap-menu).
M-x dissociated-press is a command for scrambling a file of text either word by word or character by character. Starting from a buffer of straight English, it produces extremely amusing output. The input comes from the current Emacs buffer. Dissociated Press writes its output in a buffer named ‘*Dissociation*’, and redisplays that buffer after every couple of lines (approximately) so you can read the output as it comes out.
Dissociated Press asks every so often whether to continue generating output. Answer n to stop it. You can also stop at any time by typing C-g. The dissociation output remains in the ‘*Dissociation*’ buffer for you to copy elsewhere if you wish.
Dissociated Press operates by jumping at random from one point in the buffer to another. In order to produce plausible output rather than gibberish, it insists on a certain amount of overlap between the end of one run of consecutive words or characters and the start of the next. That is, if it has just output `president' and then decides to jump to a different point in the file, it might spot the `ent' in `pentagon' and continue from there, producing `presidentagon'.20 Long sample texts produce the best results.
A positive argument to M-x dissociated-press tells it to operate character by character, and specifies the number of overlap characters. A negative argument tells it to operate word by word and specifies the number of overlap words. In this mode, whole words are treated as the elements to be permuted, rather than characters. No argument is equivalent to an argument of two. For your againformation, the output goes only into the buffer ‘*Dissociation*’. The buffer you start with is not changed.
Dissociated Press produces nearly the same results as a Markov chain based on a frequency table constructed from the sample text. It is, however, an independent, ignoriginal invention. Dissociated Press techniquitously copies several consecutive characters from the sample between random choices, whereas a Markov chain would choose randomly for each word or character. This makes for more plausible sounding results, and runs faster.
It is a mustatement that too much use of Dissociated Press can be a developediment to your real work. Sometimes to the point of outragedy. And keep dissociwords out of your documentation, if you want it to be well userenced and properbose. Have fun. Your buggestions are welcome.
If you are a little bit bored, you can try M-x hanoi. If you are considerably bored, give it a numeric argument. If you are very, very bored, try an argument of 9. Sit back and watch.
If you want a little more personal involvement, try M-x gomoku, which plays the game Go Moku with you.
M-x blackbox, M-x mpuz and M-x 5x5 are kinds of puzzles.
blackbox challenges you to determine the location of objects
inside a box by tomography. mpuz displays a multiplication
puzzle with letters standing for digits in a code that you must
guess—to guess a value, type a letter and then the digit you think it
stands for. The aim of 5x5 is to fill in all the squares.
M-x decipher helps you to cryptanalyze a buffer which is encrypted in a simple monoalphabetic substitution cipher.
M-x dunnet runs an adventure-style exploration game, which is a bigger sort of puzzle.
M-x lm runs a relatively non-participatory game in which a robot attempts to maneuver towards a tree at the center of the window based on unique olfactory cues from each of the four directions.
M-x life runs Conway's “Life” cellular automaton.
M-x morse-region converts text in a region to Morse code and M-x unmorse-region converts it back. No cause for remorse.
M-x pong plays a Pong-like game, bouncing the ball off opposing bats.
M-x solitaire plays a game of solitaire in which you jump pegs across other pegs.
M-x studlify-region studlify-cases the region, producing text like this:
M-x stUdlIfY-RegioN stUdlIfY-CaSeS thE region.
M-x tetris runs an implementation of the well-known Tetris game. Likewise, M-x snake provides an implementation of Snake.
When you are frustrated, try the famous Eliza program. Just do M-x doctor. End each input by typing <RET> twice.
When you are feeling strange, type M-x yow.
The command M-x zone plays games with the display when Emacs is idle.
This chapter talks about various topics relevant to adapting the behavior of Emacs in minor ways. See Emacs Lisp, for how to make more far-reaching changes. See X Resources, for information on using X resources to customize Emacs.
Customization that you do within Emacs normally affects only the particular Emacs session that you do it in—it does not persist between sessions unless you save the customization in a file such as .emacs or .Xdefaults that will affect future sessions. See Init File. In the customization buffer, when you save customizations for future sessions, this actually works by editing .emacs for you.
Another means of customization is the keyboard macro, which is a sequence of keystrokes to be replayed with a single command. See Keyboard Macros, for full instruction how to record, manage, and replay sequences of keys.
Minor modes are optional features which you can turn on or off. For example, Auto Fill mode is a minor mode in which <SPC> breaks lines between words as you type. All the minor modes are independent of each other and of the selected major mode. Most minor modes say in the mode line when they are on; for example, ‘Fill’ in the mode line means that Auto Fill mode is on.
Append -mode to the name of a minor mode to get the name of a
command that turns the mode on or off. Thus, the command to
enable or disable Auto Fill mode is called auto-fill-mode. These
commands are usually invoked with M-x, but you can bind keys to them
if you wish. With no argument, the function turns the mode on if it was
off and off if it was on. This is known as toggling. A positive
argument always turns the mode on, and an explicit zero argument or a
negative argument always turns it off.
Some minor modes are global: while enabled, they affect everything you do in the Emacs session, in all buffers. Other minor modes are buffer-local; they apply only to the current buffer, so you can enable the mode in certain buffers and not others.
For most minor modes, the command name is also the name of a
variable. The variable's value is non-nil if the mode is
enabled and nil if it is disabled. Some minor-mode commands
work by just setting the variable. For example, the command
abbrev-mode works by setting the value of abbrev-mode as
a variable; it is this variable that directly turns Abbrev mode on and
off. You can directly set the variable's value instead of calling the
mode function. For other minor modes, you need to either set the
variable through the Customize interface or call the mode function to
correctly enable or disable the mode. To check which of these two
possibilities applies to a given minor mode, use C-h v to ask
for documentation on the variable name.
For minor mode commands that work by just setting the minor mode variable, that variable provides a good way for Lisp programs to turn minor modes on and off; it is also useful in a file's local variables list (see File Variables). But please think twice before setting minor modes with a local variables list, because most minor modes are a matter of user preference—other users editing the same file might not want the same minor modes you prefer.
The most useful buffer-local minor modes include Abbrev mode, Auto Fill mode, Auto Save mode, Font-Lock mode, Glasses mode, ISO Accents mode, Outline minor mode, Overwrite mode, and Binary Overwrite mode.
Abbrev mode allows you to define abbreviations that automatically expand as you type them. For example, ‘amd’ might expand to ‘abbrev mode’. See Abbrevs, for full information.
Auto Fill mode allows you to enter filled text without breaking lines explicitly. Emacs inserts newlines as necessary to prevent lines from becoming too long. See Filling.
Auto Save mode causes the contents of a buffer to be saved periodically to reduce the amount of work you can lose in case of a system crash. See Auto Save.
Enriched mode enables editing and saving of formatted text. See Formatted Text.
Flyspell mode automatically highlights misspelled words. See Spelling.
Font-Lock mode automatically highlights certain textual units found in programs, such as comments, strings, and function names being defined. This requires a window system that can display multiple fonts. See Faces.
ISO Accents mode makes the characters ‘`’, ‘'’, ‘"’, ‘^’, ‘/’ and ‘~’ combine with the following letter, to produce an accented letter in the ISO Latin-1 character set. The newer and more general feature of input methods more or less supersedes ISO Accents mode. See Single-Byte Character Support.
Outline minor mode provides the same facilities as the major mode called Outline mode; but since it is a minor mode instead, you can combine it with any major mode. See Outline Mode.
Overwrite mode causes ordinary printing characters to replace existing text instead of shoving it to the right. For example, if point is in front of the ‘B’ in ‘FOOBAR’, then in Overwrite mode typing a G changes it to ‘FOOGAR’, instead of producing ‘FOOGBAR’ as usual. In Overwrite mode, the command C-q inserts the next character whatever it may be, even if it is a digit—this gives you a way to insert a character instead of replacing an existing character.
The command overwrite-mode is an exception to the rule that
commands which toggle minor modes are normally not bound to keys: it is
bound to the <INSERT> function key. This is because many other
programs bind <INSERT> to similar functions.
Binary Overwrite mode is a variant of Overwrite mode for editing binary files; it treats newlines and tabs like other characters, so that they overwrite other characters and can be overwritten by them. In Binary Overwrite mode, digits after C-q specify an octal character code, as usual.
Here are some useful minor modes that normally apply to all buffers at once. Since Line Number mode and Transient Mark mode can be enabled or disabled just by setting the value of the minor mode variable, you can set them differently for particular buffers, by explicitly making the corresponding variable local in those buffers. See Locals.
Icomplete mode displays an indication of available completions when you are in the minibuffer and completion is active. See Completion Options.
Line Number mode enables continuous display in the mode line of the line number of point, and Column Number mode enables display of the column number. See Mode Line.
Scroll Bar mode gives each window a scroll bar (see Scroll Bars). Menu Bar mode gives each frame a menu bar (see Menu Bars). Both of these modes are enabled by default when you use the X Window System.
In Transient Mark mode, every change in the buffer contents “deactivates” the mark, so that commands that operate on the region will get an error. This means you must either set the mark, or explicitly “reactivate” it, before each command that uses the region. The advantage of Transient Mark mode is that Emacs can display the region highlighted. See Mark.
Emacs has many settings which have values that you can specify in order to customize various commands. Many are documented in this manual. Most settings are user options—that is to say, Lisp variables (see Variables)—so their names appear in the Variable Index (see Variable Index). The other settings are faces and their attributes (see Faces).
You can browse interactively through settings and change them using M-x customize. This command creates a customization buffer, which offers commands to navigate through a logically organized structure of the Emacs settings; you can also use it to edit and set their values, and to save settings permanently in your ~/.emacs file (see Init File).
The appearance of the example buffers in this section is typically different under a window system, since faces are then used to indicate buttons and editable fields.
For customization purposes, settings are organized into groups
to help you find them. Groups are collected into bigger groups, all
the way up to a master group called Emacs.
M-x customize creates a customization buffer that shows the
top-level Emacs group and the second-level groups immediately
under it. It looks like this, in part:
/- Emacs group: ---------------------------------------------------\
[State]: visible group members are all at standard settings.
Customization of the One True Editor.
See also [Manual].
Editing group: [Go to Group]
Basic text editing facilities.
External group: [Go to Group]
Interfacing to external utilities.
more second-level groups
\- Emacs group end ------------------------------------------------/
This says that the buffer displays the contents of the Emacs
group. The other groups are listed because they are its contents. But
they are listed differently, without indentation and dashes, because
their contents are not included. Each group has a single-line
documentation string; the Emacs group also has a ‘[State]’
line.
Most of the text in the customization buffer is read-only, but it typically includes some editable fields that you can edit. There are also buttons, which do something when you invoke them. To invoke a button, either click on it with Mouse-1, or move point to it and type <RET>.
For example, the phrase ‘[Go to Group]’ that appears in a second-level group is a button. Invoking it creates a new customization buffer, which shows that group and its contents. This is a kind of hypertext link to another group.
The Emacs group includes a few settings, but mainly it
contains other groups, which contain more groups, which contain the
settings. By browsing the hierarchy of groups, you will eventually
find the feature you are interested in customizing. Then you can use
the customization buffer to set that feature's settings. You can also
go straight to a particular group by name, using the command M-x
customize-group.
M-x customize-browse is another way to browse the available settings. This command creates a special customization buffer which shows only the names of groups and settings, and puts them in a structure.
In this buffer, you can show the contents of a group by invoking ‘[+]’. When the group contents are visible, this button changes to ‘[-]’; invoking that hides the group contents.
Each setting in this buffer has a button which says ‘[Group]’, ‘[Option]’ or ‘[Face]’. Invoking this button creates an ordinary customization buffer showing just that group and its contents, just that user option, or just that face. This is the way to change settings that you find with M-x customize-browse.
If you can guess part of the name of the settings you are interested
in, M-x customize-apropos is another way to search for settings.
However, unlike customize and customize-browse,
customize-apropos can only find groups and settings that are
loaded in the current Emacs session. See Customizing Specific Items.
Here is an example of what a variable (a user option) looks like in the customization buffer:
Kill Ring Max: [Hide Value] 60
[State]: STANDARD.
Maximum length of kill ring before oldest elements are thrown away.
The text following ‘[Hide Value]’, ‘60’ in this case, indicates the current value of the variable. If you see ‘[Show Value]’ instead of ‘[Hide Value]’, it means that the value is hidden; the customization buffer initially hides values that take up several lines. Invoke ‘[Show Value]’ to show the value.
The line after the variable name indicates the customization state of the variable: in the example above, it says you have not changed the option yet. The ‘[State]’ button at the beginning of this line gives you a menu of various operations for customizing the variable.
The line after the ‘[State]’ line displays the beginning of the variable's documentation string. If there are more lines of documentation, this line ends with a ‘[More]’ button; invoke that to show the full documentation string.
To enter a new value for ‘Kill Ring Max’, move point to the value and edit it textually. For example, you can type M-d, then insert another number. As you begin to alter the text, you will see the ‘[State]’ line change to say that you have edited the value:
[State]: EDITED, shown value does not take effect until you set or ...
save it.
Editing the value does not actually set the variable. To do that, you must set the variable. To do this, invoke the ‘[State]’ button and choose ‘Set for Current Session’.
The state of the variable changes visibly when you set it:
[State]: SET for current session only.
You don't have to worry about specifying a value that is not valid; the ‘Set for Current Session’ operation checks for validity and will not install an unacceptable value.
While editing a field that is a file name, directory name,
command name, or anything else for which completion is defined, you
can type M-<TAB> (widget-complete) to do completion.
(<ESC> <TAB> and C-M-i do the same thing.)
Some variables have a small fixed set of possible legitimate values. These variables don't let you edit the value textually. Instead, a ‘[Value Menu]’ button appears before the value; invoke this button to change the value. For a boolean “on or off” value, the button says ‘[Toggle]’, and it changes to the other value. ‘[Value Menu]’ and ‘[Toggle]’ simply edit the buffer; the changes take real effect when you use the ‘Set for Current Session’ operation.
Some variables have values with complex structure. For example, the
value of file-coding-system-alist is an association list. Here
is how it appears in the customization buffer:
File Coding System Alist: [Hide Value]
[INS] [DEL] File regexp: \.elc\'
Choice: [Value Menu] Encoding/decoding pair:
Decoding: emacs-mule
Encoding: emacs-mule
[INS] [DEL] File regexp: \(\`\|/\)loaddefs.el\'
Choice: [Value Menu] Encoding/decoding pair:
Decoding: raw-text
Encoding: raw-text-unix
[INS] [DEL] File regexp: \.tar\'
Choice: [Value Menu] Encoding/decoding pair:
Decoding: no-conversion
Encoding: no-conversion
[INS] [DEL] File regexp:
Choice: [Value Menu] Encoding/decoding pair:
Decoding: undecided
Encoding: nil
[INS]
[State]: STANDARD.
Alist to decide a coding system to use for a file I/O ...
operation. [Hide Rest]
The format is ((PATTERN . VAL) ...),
where PATTERN is a regular expression matching a file name,
[...more lines of documentation...]
Each association in the list appears on four lines, with several editable fields and/or buttons. You can edit the regexps and coding systems using ordinary editing commands. You can also invoke ‘[Value Menu]’ to switch to a different kind of value—for instance, to specify a function instead of a pair of coding systems.
To delete an association from the list, invoke the ‘[DEL]’ button for that item. To add an association, invoke ‘[INS]’ at the position where you want to add it. There is an ‘[INS]’ button between each pair of association, another at the beginning and another at the end, so you can add the new association at any position in the list.
Two special commands, <TAB> and S-<TAB>, are useful
for moving through the customization buffer. <TAB>
(widget-forward) moves forward to the next button or editable
field; S-<TAB> (widget-backward) moves backward to
the previous button or editable field.
Typing <RET> on an editable field also moves forward, just like <TAB>. We set it up this way because people often type <RET> when they are finished editing a field. To insert a newline within an editable field, use C-o or C-q C-j.
Setting the variable changes its value in the current Emacs session; saving the value changes it for future sessions as well. To save the variable, invoke ‘[State]’ and select the ‘Save for Future Sessions’ operation. This works by writing code so as to set the variable again, each time you start Emacs (see Saving Customizations).
You can also restore the variable to its standard value by invoking ‘[State]’ and selecting the ‘Erase Customization’ operation. There are actually four reset operations:
Sometimes it is useful to record a comment about a specific customization. Use the ‘Add Comment’ item from the ‘[State]’ menu to create a field for entering the comment. The comment you enter will be saved, and displayed again if you again view the same variable in a customization buffer, even in another session.
The state of a group indicates whether anything in that group has been edited, set or saved.
Near the top of the customization buffer there are two lines of buttons:
[Set for Current Session] [Save for Future Sessions]
[Reset to Current] [Reset to Saved] [Erase Customization] [Finish]
Invoking ‘[Finish]’ either buries or kills this customization
buffer according to the setting of the option
custom-buffer-done-kill; the default is to bury the buffer.
Each of the other buttons performs an operation—set, save or
reset—on each of the settings in the buffer that could meaningfully
be set, saved or reset. They do not operate on settings whose values
are hidden, nor on subgroups not visible in the buffer.
The customization buffer normally saves customizations in
~/.emacs. If you wish, you can save customizations in another
file instead. To make this work, your ~/.emacs should set
custom-file to the name of that file. Then you should load the
file by calling load. For example:
(setq custom-file "~/.emacs-custom.el")
(load custom-file)
You can also use custom-file to specify different
customization files for different Emacs versions, like this:
(cond ((< emacs-major-version 21)
;; Emacs 20 customization.
(setq custom-file "~/.custom-20.el"))
((and (= emacs-major-version 21) (< emacs-minor-version 4))
;; Emacs 21 customization, before version 21.4.
(setq custom-file "~/.custom-21.el"))
((< emacs-major-version 22)
;; Emacs version 21.4 or later.
(setq custom-file "~/.custom-21.4.el"))
(t
;; Emacs version 22.1 or later.
(setq custom-file "~/.custom-22.el")))
(load custom-file)
If Emacs was invoked with the -q or --no-init-file options (see Initial Options), it will not let you save your customizations in your ~/.emacs init file. This is because saving customizations from such a session would wipe out all the other customizations you might have on your init file.
In addition to variables, some customization groups also include faces. When you show the contents of a group, both the variables and the faces in the group appear in the customization buffer. Here is an example of how a face looks:
Custom Changed Face:(sample) [Hide Face]
[State]: STANDARD.
Face used when the customize item has been changed.
Parent groups: [Custom Magic Faces]
Attributes: [ ] Font Family: *
[ ] Width: *
[ ] Height: *
[ ] Weight: *
[ ] Slant: *
[ ] Underline: *
[ ] Overline: *
[ ] Strike-through: *
[ ] Box around text: *
[ ] Inverse-video: *
[X] Foreground: white (sample)
[X] Background: blue (sample)
[ ] Stipple: *
[ ] Inherit: *
Each face attribute has its own line. The ‘[x]’ button before the attribute name indicates whether the attribute is enabled; ‘[X]’ means that it's enabled, and ‘[ ]’ means that it's disabled. You can enable or disable the attribute by clicking that button. When the attribute is enabled, you can change the attribute value in the usual ways.
For the colors, you can specify a color name (use M-x list-colors-display for a list of them) or a hexadecimal color specification of the form ‘#rrggbb’. (‘#000000’ is black, ‘#ff0000’ is red, ‘#00ff00’ is green, ‘#0000ff’ is blue, and ‘#ffffff’ is white.) On a black-and-white display, the colors you can use for the background are ‘black’, ‘white’, ‘gray’, ‘gray1’, and ‘gray3’. Emacs supports these shades of gray by using background stipple patterns instead of a color.
Setting, saving and resetting a face work like the same operations for variables (see Changing a Variable).
A face can specify different appearances for different types of display. For example, a face can make text red on a color display, but use a bold font on a monochrome display. To specify multiple appearances for a face, select ‘Show all display specs’ in the menu you get from invoking ‘[State]’.
Another more basic way to set the attributes of a specific face is with M-x modify-face. This command reads the name of a face, then reads the attributes one by one. For the color and stipple attributes, the attribute's current value is the default—type just <RET> if you don't want to change that attribute. Type ‘none’ if you want to clear out the attribute.
Instead of finding the setting you want to change by navigating the structure of groups, here are other ways to specify the settings that you want to customize.
If you want to alter a particular variable with the customization buffer, and you know its name, you can use the command M-x customize-variable and specify the variable name. This sets up the customization buffer with just one variable—the one that you asked for. Editing, setting and saving the value work as described above, but only for the specified variable. Minibuffer completion is handy if you only know part of the name. However, this command can only see options that have been loaded in the current Emacs session.
Likewise, you can modify a specific face, chosen by name, using M-x customize-face. By default it operates on the face used on the character after point.
You can also set up the customization buffer with a specific group, using M-x customize-group. The immediate contents of the chosen group, including variables, faces, and other groups, all appear as well (even if not already loaded). However, the subgroups' own contents are not included.
To control more precisely what to customize, you can use M-x customize-apropos. You specify a regular expression as argument; then all loaded settings and groups whose names match this regular expression are set up in the customization buffer. If you specify an empty regular expression, this includes all loaded groups and settings—which takes a long time to set up.
When you upgrade to a new Emacs version, you might want to customize new settings and settings whose meanings or default values have changed. To do this, use M-x customize-changed and specify a previous Emacs version number using the minibuffer. It creates a customization buffer which shows all the settings and groups whose definitions have been changed since the specified version, loading them if necessary.
If you change settings and then decide the change was a mistake, you can use two special commands to revisit your previous changes. Use M-x customize-saved to look at the settings that you have saved. Use M-x customize-customized to look at the settings that you have set but not saved.
Custom themes are collections of settings that can be enabled or disabled as a unit. You can use Custom themes to switch quickly and easily between various collections of settings, and to transfer such collections from one computer to another.
To define a Custom theme, use the command M-x customize-create-theme, which brings up a buffer named ‘*New Custom Theme*’. At the top of the buffer is an editable field where you can specify the name of the theme. To add a customization option to the theme, click on the ‘INS’ button to open up a field where you can insert the name of the option. The current value of that option is applied to the theme. After adding as many options as you like, click on ‘Done’ to save the Custom theme.
Saving a Custom theme named foo writes its definition into the
file foo-theme.el, in the directory ~/.emacs.d/
(you can specify the directory by setting
custom-theme-directory).
You can load the themes you've previously defined with the command
load-theme. It prompts for a theme name in the minibuffer, and
loads that theme from the theme file. It also enables the
theme, which means putting its settings into effect. An enabled theme
can be disabled with the command M-x disable-theme; this
returns the options specified in the theme to their original values.
To re-enable the theme, use the command M-x enable-theme.
To enable a Custom theme named foo whenever Emacs is started up,
add the line (load-theme 'foo) to your .emacs file
(see Init File).
Enabling a custom theme does not disable the themes already enabled; instead, they are all enabled together. If two enabled Custom themes specify different values for an option, the last theme to be enabled takes effect.
The options that you set in the ordinary customization buffer (see Easy Customization) are also considered part of a Custom theme, called ‘user’. The ‘user’ theme is always enabled, and always takes precedence over all other enabled Custom themes. Additionally, the ‘user’ theme is recorded in your .emacs file, rather than a user-theme.el file.
A variable is a Lisp symbol which has a value. The symbol's name is also called the name of the variable. A variable name can contain any characters that can appear in a file, but conventionally variable names consist of words separated by hyphens. A variable can have a documentation string which describes what kind of value it should have and how the value will be used.
Emacs Lisp allows any variable (with a few exceptions) to have any
kind of value, but most variables that Emacs uses need a value of a
certain type. Often the value should always be a string, or should
always be a number. Sometimes we say that a certain feature is turned
on if a variable is “non-nil,” meaning that if the variable's
value is nil, the feature is off, but the feature is on for
any other value. The conventional value to use to turn on the
feature—since you have to pick one particular value when you set the
variable—is t.
Emacs uses many Lisp variables for internal record keeping, but the most interesting variables for a non-programmer user are those meant for users to change—the user options.
Each user option that you can set with the customization buffer is in fact a Lisp variable. Emacs does not (usually) change the values of these variables; instead, you set the values, and thereby alter and control the behavior of certain Emacs commands. Use of the customization buffer is explained above (see Easy Customization); here we describe other aspects of Emacs variables.
describe-variable).
To examine the value of a single variable, use C-h v
(describe-variable), which reads a variable name using the
minibuffer, with completion. It displays both the value and the
documentation of the variable. For example,
C-h v fill-column <RET>
displays something like this:
fill-column's value is 70
Documentation:
*Column beyond which automatic line-wrapping should happen.
Automatically becomes buffer-local when set in any fashion.
The star at the beginning of the documentation indicates that this variable is a user option. C-h v is not restricted to user options; it allows any variable name.
The most convenient way to set a specific user option variable is with M-x set-variable. This reads the variable name with the minibuffer (with completion), and then reads a Lisp expression for the new value using the minibuffer a second time (you can insert the old value into the minibuffer for editing via M-n). For example,
M-x set-variable <RET> fill-column <RET> 75 <RET>
sets fill-column to 75.
M-x set-variable is limited to user option variables, but you can
set any variable with a Lisp expression, using the function setq.
Here is a setq expression to set fill-column:
(setq fill-column 75)
To execute an expression like this one, go to the ‘*scratch*’ buffer, type in the expression, and then type C-j. See Lisp Interaction.
Setting variables, like all means of customizing Emacs except where otherwise stated, affects only the current Emacs session. The only way to alter the variable in future sessions is to put something in the ~/.emacs file to set it those sessions (see Init File).
Hooks are an important mechanism for customization of Emacs. A hook is a Lisp variable which holds a list of functions, to be called on some well-defined occasion. (This is called running the hook.) The individual functions in the list are called the hook functions of the hook. With rare exceptions, hooks in Emacs are empty when Emacs starts up, so the only hook functions in any given hook are the ones you explicitly put there as customization.
Most major modes run one or more mode hooks as the last step of
initialization. This makes it easy for you to customize the behavior of
the mode, by setting up a hook function to override the local variable
assignments already made by the mode. But hooks are also used in other
contexts. For example, the hook suspend-hook runs just before
Emacs suspends itself (see Exiting).
Most Emacs hooks are normal hooks. This means that running the hook operates by calling all the hook functions, unconditionally, with no arguments. We have made an effort to keep most hooks normal so that you can use them in a uniform way. Every variable in Emacs whose name ends in ‘-hook’ is a normal hook.
There are also a few abnormal hooks. These variables' names end
in ‘-hooks’ or ‘-functions’, instead of ‘-hook’. What
makes these hooks abnormal is that there is something peculiar about the
way its functions are called—perhaps they are given arguments, or
perhaps the values they return are used in some way. For example,
find-file-not-found-functions (see Visiting) is abnormal because
as soon as one hook function returns a non-nil value, the rest
are not called at all. The documentation of each abnormal hook variable
explains in detail what is peculiar about it.
You can set a hook variable with setq like any other Lisp
variable, but the recommended way to add a hook function to a hook
(either normal or abnormal) is by calling add-hook. You can
specify any valid Lisp function as the hook function, provided it can
handle the proper number of arguments (zero arguments, in the case of
a normal hook). Of course, not every Lisp function is useful
in any particular hook.
For example, here's how to set up a hook to turn on Auto Fill mode when entering Text mode and other modes based on Text mode:
(add-hook 'text-mode-hook 'turn-on-auto-fill)
The next example shows how to use a hook to customize the indentation of C code. (People often have strong personal preferences for one format compared to another.) Here the hook function is an anonymous lambda expression.
(setq my-c-style
'((c-comment-only-line-offset . 4)
(c-cleanup-list . (scope-operator
empty-defun-braces
defun-close-semi))
(c-offsets-alist . ((arglist-close . c-lineup-arglist)
(substatement-open . 0)))))
(add-hook 'c-mode-common-hook
'(lambda ()
(c-add-style "my-style" my-c-style t)))
It is best to design your hook functions so that the order in which they are executed does not matter. Any dependence on the order is “asking for trouble.” However, the order is predictable: the most recently added hook functions are executed first.
If you play with adding various different versions of a hook
function by calling add-hook over and over, remember that all
the versions you added will remain in the hook variable together. You
can clear out individual functions with remove-hook, or do
(setq hook-variable nil) to remove everything.
Almost any variable can be made local to a specific Emacs buffer. This means that its value in that buffer is independent of its value in other buffers. A few variables are always local in every buffer. Every other Emacs variable has a global value which is in effect in all buffers that have not made the variable local.
M-x make-local-variable reads the name of a variable and makes it local to the current buffer. Further changes in this buffer will not affect others, and further changes in the global value will not affect this buffer.
M-x make-variable-buffer-local reads the name of a variable and
changes the future behavior of the variable so that it will become local
automatically when it is set. More precisely, once a variable has been
marked in this way, the usual ways of setting the variable automatically
do make-local-variable first. We call such variables
per-buffer variables.
Major modes (see Major Modes) always make variables local to the
buffer before setting the variables. This is why changing major modes
in one buffer has no effect on other buffers. Minor modes also work by
setting variables—normally, each minor mode has one controlling
variable which is non-nil when the mode is enabled (see Minor Modes). For most minor modes, the controlling variable is per buffer.
Emacs contains a number of variables that are always per-buffer.
These include abbrev-mode, auto-fill-function,
case-fold-search, comment-column, ctl-arrow,
fill-column, fill-prefix, indent-tabs-mode,
left-margin, mode-line-format, overwrite-mode,
selective-display-ellipses, selective-display,
tab-width, and truncate-lines. Some other variables are
always local in every buffer, but they are used for internal
purposes.
A few variables cannot be local to a buffer because they are always local to each display instead (see Multiple Displays). If you try to make one of these variables buffer-local, you'll get an error message.
M-x kill-local-variable reads the name of a variable and makes it cease to be local to the current buffer. The global value of the variable henceforth is in effect in this buffer. Setting the major mode kills all the local variables of the buffer except for a few variables specially marked as permanent locals.
To set the global value of a variable, regardless of whether the
variable has a local value in the current buffer, you can use the Lisp
construct setq-default. This construct is used just like
setq, but it sets variables' global values instead of their local
values (if any). When the current buffer does have a local value, the
new global value may not be visible until you switch to another buffer.
Here is an example:
(setq-default fill-column 75)
setq-default is the only way to set the global value of a variable
that has been marked with make-variable-buffer-local.
Lisp programs can use default-value to look at a variable's
default value. This function takes a symbol as argument and returns its
default value. The argument is evaluated; usually you must quote it
explicitly. For example, here's how to obtain the default value of
fill-column:
(default-value 'fill-column)
A file can specify local variable values for use when you edit the file with Emacs. Visiting the file checks for local variable specifications; it automatically makes these variables local to the buffer, and sets them to the values specified in the file.
There are two ways to specify local variable values: in the first line, or with a local variables list. Here's how to specify them in the first line:
-*- mode: modename; var: value; ... -*-
You can specify any number of variables/value pairs in this way, each
pair with a colon and semicolon as shown above. mode:
modename; specifies the major mode; this should come first in the
line. The values are not evaluated; they are used literally.
Here is an example that specifies Lisp mode and sets two variables with
numeric values:
;; -*- mode: Lisp; fill-column: 75; comment-column: 50; -*-
You can also specify the coding system for a file in this way: just
specify a value for the “variable” named coding. The “value”
must be a coding system name that Emacs recognizes. See Coding Systems. ‘unibyte: t’ specifies unibyte loading for a
particular Lisp file. See Enabling Multibyte.
The eval pseudo-variable, described below, can be specified in
the first line as well.
In shell scripts, the first line is used to identify the script interpreter, so you cannot put any local variables there. To accommodate for this, when Emacs visits a shell script, it looks for local variable specifications in the second line.
A local variables list goes near the end of the file, in the last page. (It is often best to put it on a page by itself.) The local variables list starts with a line containing the string ‘Local Variables:’, and ends with a line containing the string ‘End:’. In between come the variable names and values, one set per line, as ‘variable: value’. The values are not evaluated; they are used literally. If a file has both a local variables list and a ‘-*-’ line, Emacs processes everything in the ‘-*-’ line first, and everything in the local variables list afterward.
Here is an example of a local variables list:
;;; Local Variables: ***
;;; mode:lisp ***
;;; comment-column:0 ***
;;; comment-start: ";;; " ***
;;; comment-end:"***" ***
;;; End: ***
As you see, each line starts with the prefix ‘;;; ’ and each line ends with the suffix ‘ ***’. Emacs recognizes these as the prefix and suffix based on the first line of the list, by finding them surrounding the magic string ‘Local Variables:’; then it automatically discards them from the other lines of the list.
The usual reason for using a prefix and/or suffix is to embed the
local variables list in a comment, so it won't confuse other programs
that the file is intended as input for. The example above is for a
language where comment lines start with ‘;;; ’ and end with
‘***’; the local values for comment-start and
comment-end customize the rest of Emacs for this unusual
syntax. Don't use a prefix (or a suffix) if you don't need one.
If you write a multi-line string value, you should put the prefix and suffix on each line, even lines that start or end within the string. They will be stripped off for processing the list. If you want to split a long string across multiple lines of the file, you can use backslash-newline, which is ignored in Lisp string constants. Here's an example of doing this:
# Local Variables:
# compile-command: "cc foo.c -Dfoo=bar -Dhack=whatever \
# -Dmumble=blaah"
# End:
Some “variable names” have special meanings in a local variables
list. Specifying the “variable” mode really sets the major
mode, while any value specified for the “variable” eval is
simply evaluated as an expression (its value is ignored). A value for
coding specifies the coding system for character code
conversion of this file, and a value of t for unibyte
says to visit the file in a unibyte buffer. These four “variables”
are not really variables; setting them in any other context has no
special meaning.
If mode is used to set a major mode, it should be the
first “variable” in the list. Otherwise, the entries that precede
it will usually be ignored, since most modes kill all local variables
as part of their initialization.
You can use the mode “variable” to set minor modes as well
as the major modes; in fact, you can use it more than once, first to
set the major mode and then to set minor modes which are specific to
particular buffers. But most minor modes should not be specified in
the file at all, regardless of how, because they represent user
preferences.
For example, you may be tempted to try to turn on Auto Fill mode with a local variable list. That is a mistake. The choice of Auto Fill mode or not is a matter of individual taste, not a matter of the contents of particular files. If you want to use Auto Fill, set up major mode hooks with your .emacs file to turn it on (when appropriate) for you alone (see Init File). Don't use a local variable list to impose your taste on everyone.
The start of the local variables list must be no more than 3000 characters from the end of the file, and must be in the last page if the file is divided into pages. Otherwise, Emacs will not notice it is there. The purpose of this rule is so that a stray ‘Local Variables:’ not in the last page does not confuse Emacs, and so that visiting a long file that is all one page and has no local variables list need not take the time to search the whole file.
Use the command normal-mode to reset the local variables and
major mode of a buffer according to the file name and contents,
including the local variables list if any. See Choosing Modes.
The variable enable-local-variables controls whether to process
local variables in files, and thus gives you a chance to override them.
Its default value is t, which means do process local variables in
files. If you set the value to nil, Emacs simply ignores local
variables in files. Any other value says to query you about each file
that has local variables, showing you the local variable specifications
so you can judge.
The eval “variable,” and certain actual variables, create a
special risk; when you visit someone else's file, local variable
specifications for these could affect your Emacs in arbitrary ways.
Therefore, the variable enable-local-eval controls whether Emacs
processes eval variables, as well variables with names that end
in ‘-hook’, ‘-hooks’, ‘-function’ or ‘-functions’,
and certain other variables. The three possibilities for the variable's
value are t, nil, and anything else, just as for
enable-local-variables. The default is maybe, which is
neither t nor nil, so normally Emacs does ask for
confirmation about file settings for these variables.
The safe-local-eval-forms is a customizable list of eval
forms which are safe to eval, so Emacs should not ask for
confirmation to evaluate these forms, even if
enable-local-variables says to ask for confirmation in general.
This section describes key bindings, which map keys to commands, and keymaps, which record key bindings. It also explains how to customize key bindings.
Recall that a command is a Lisp function whose definition provides for interactive use. Like every Lisp function, a command has a function name which usually consists of lower-case letters and hyphens.
The bindings between key sequences and command functions are recorded in data structures called keymaps. Emacs has many of these, each used on particular occasions.
Recall that a key sequence (key, for short) is a sequence of input events that have a meaning as a unit. Input events include characters, function keys and mouse buttons—all the inputs that you can send to the computer with your terminal. A key sequence gets its meaning from its binding, which says what command it runs. The function of keymaps is to record these bindings.
The global keymap is the most important keymap because it is always in effect. The global keymap defines keys for Fundamental mode; most of these definitions are common to most or all major modes. Each major or minor mode can have its own keymap which overrides the global definitions of some keys.
For example, a self-inserting character such as g is
self-inserting because the global keymap binds it to the command
self-insert-command. The standard Emacs editing characters such
as C-a also get their standard meanings from the global keymap.
Commands to rebind keys, such as M-x global-set-key, actually work
by storing the new binding in the proper place in the global map.
See Rebinding.
Meta characters work differently; Emacs translates each Meta character into a pair of characters starting with <ESC>. When you type the character M-a in a key sequence, Emacs replaces it with <ESC> a. A meta key comes in as a single input event, but becomes two events for purposes of key bindings. The reason for this is historical, and we might change it someday.
Most modern keyboards have function keys as well as character keys. Function keys send input events just as character keys do, and keymaps can have bindings for them.
On text terminals, typing a function key actually sends the computer a sequence of characters; the precise details of the sequence depends on which function key and on the model of terminal you are using. (Often the sequence starts with <ESC> [.) If Emacs understands your terminal type properly, it recognizes the character sequences forming function keys wherever they occur in a key sequence (not just at the beginning). Thus, for most purposes, you can pretend the function keys reach Emacs directly and ignore their encoding as character sequences.
Mouse buttons also produce input events. These events come with other data—the window and position where you pressed or released the button, and a time stamp. But only the choice of button matters for key bindings; the other data matters only if a command looks at it. (Commands designed for mouse invocation usually do look at the other data.)
A keymap records definitions for single events. Interpreting a key sequence of multiple events involves a chain of keymaps. The first keymap gives a definition for the first event; this definition is another keymap, which is used to look up the second event in the sequence, and so on.
Key sequences can mix function keys and characters. For example, C-x <SELECT> is meaningful. If you make <SELECT> a prefix key, then <SELECT> C-n makes sense. You can even mix mouse events with keyboard events, but we recommend against it, because such key sequences are inconvenient to use.
As a user, you can redefine any key; but it is usually best to stick to key sequences that consist of C-c followed by a letter (upper or lower case). These keys are “reserved for users,” so they won't conflict with any properly designed Emacs extension. The function keys <F5> through <F9> are also reserved for users. If you redefine some other key, your definition may be overridden by certain extensions or major modes which redefine the same key.
A prefix key such as C-x or <ESC> has its own keymap, which holds the definition for the event that immediately follows that prefix.
The definition of a prefix key is usually the keymap to use for
looking up the following event. The definition can also be a Lisp
symbol whose function definition is the following keymap; the effect is
the same, but it provides a command name for the prefix key that can be
used as a description of what the prefix key is for. Thus, the binding
of C-x is the symbol Control-X-prefix, whose function
definition is the keymap for C-x commands. The definitions of
C-c, C-x, C-h and <ESC> as prefix keys appear in
the global map, so these prefix keys are always available.
Aside from ordinary prefix keys, there is a fictitious “prefix key” which represents the menu bar; see Menu Bar, for special information about menu bar key bindings. Mouse button events that invoke pop-up menus are also prefix keys; see Menu Keymaps, for more details.
Some prefix keymaps are stored in variables with names:
ctl-x-map is the variable name for the map used for characters that
follow C-x.
help-map is for characters that follow C-h.
esc-map is for characters that follow <ESC>. Thus, all Meta
characters are actually defined by this map.
ctl-x-4-map is for characters that follow C-x 4.
mode-specific-map is for characters that follow C-c.
So far we have explained the ins and outs of the global map. Major modes customize Emacs by providing their own key bindings in local keymaps. For example, C mode overrides <TAB> to make it indent the current line for C code. Portions of text in the buffer can specify their own keymaps to substitute for the keymap of the buffer's major mode.
Minor modes can also have local keymaps. Whenever a minor mode is in effect, the definitions in its keymap override both the major mode's local keymap and the global keymap.
The local keymaps for Lisp mode and several other major modes always
exist even when not in use. These are kept in variables named
lisp-mode-map and so on. For major modes less often used, the
local keymap is normally constructed only when the mode is used for the
first time in a session. This is to save space. If you wish to change
one of these keymaps, you must use the major mode's mode
hook—see below.
All minor mode keymaps are created in advance. There is no way to defer their creation until the first time the minor mode is enabled.
A local keymap can locally redefine a key as a prefix key by defining it as a prefix keymap. If the key is also defined globally as a prefix, then its local and global definitions (both keymaps) effectively combine: both of them are used to look up the event that follows the prefix key. Thus, if the mode's local keymap defines C-c as another keymap, and that keymap defines C-z as a command, this provides a local meaning for C-c C-z. This does not affect other sequences that start with C-c; if those sequences don't have their own local bindings, their global bindings remain in effect.
Another way to think of this is that Emacs handles a multi-event key sequence by looking in several keymaps, one by one, for a binding of the whole key sequence. First it checks the minor mode keymaps for minor modes that are enabled, then it checks the major mode's keymap, and then it checks the global keymap. This is not precisely how key lookup works, but it's good enough for understanding ordinary circumstances.
To change the local bindings of a major mode, you must change the mode's local keymap. Normally you must wait until the first time the mode is used, because most major modes don't create their keymaps until then. If you want to specify something in your ~/.emacs file to change a major mode's bindings, you must use the mode's mode hook to delay the change until the mode is first used.
For example, the command texinfo-mode to select Texinfo mode
runs the hook texinfo-mode-hook. Here's how you can use the hook
to add local bindings (not very useful, we admit) for C-c n and
C-c p in Texinfo mode:
(add-hook 'texinfo-mode-hook
'(lambda ()
(define-key texinfo-mode-map "\C-cp"
'backward-paragraph)
(define-key texinfo-mode-map "\C-cn"
'forward-paragraph)))
See Hooks.
The minibuffer has its own set of local keymaps; they contain various completion and exit commands.
minibuffer-local-map is used for ordinary input (no completion).
minibuffer-local-ns-map is similar, except that <SPC> exits
just like <RET>. This is used mainly for Mocklisp compatibility.
minibuffer-local-completion-map is for permissive completion.
minibuffer-local-must-match-map is for strict completion and
for cautious completion.
minibuffer-local-filename-completion-map and
minibuffer-local-must-match-filename-map are like the two
previous ones, but they are specifically for file name completion.
They do not bind <SPC>.
The way to redefine an Emacs key is to change its entry in a keymap. You can change the global keymap, in which case the change is effective in all major modes (except those that have their own overriding local definitions for the same key). Or you can change the current buffer's local map, which affects all buffers using the same major mode.
For example, suppose you like to execute commands in a subshell within
an Emacs buffer, instead of suspending Emacs and executing commands in
your login shell. Normally, C-z is bound to the function
suspend-emacs (when not using the X Window System), but you can
change C-z to invoke an interactive subshell within Emacs, by
binding it to shell as follows:
M-x global-set-key <RET> C-z shell <RET>
global-set-key reads the command name after the key. After you
press the key, a message like this appears so that you can confirm that
you are binding the key you want:
Set key C-z to command:
You can redefine function keys and mouse events in the same way; just type the function key or click the mouse when it's time to specify the key to rebind.
You can rebind a key that contains more than one event in the same way. Emacs keeps reading the key to rebind until it is a complete key (that is, not a prefix key). Thus, if you type C-f for key, that's the end; the minibuffer is entered immediately to read cmd. But if you type C-x, another character is read; if that is 4, another character is read, and so on. For example,
M-x global-set-key <RET> C-x 4 $ spell-other-window <RET>
redefines C-x 4 $ to run the (fictitious) command
spell-other-window.
The two-character keys consisting of C-c followed by a letter are reserved for user customizations. Lisp programs are not supposed to define these keys, so the bindings you make for them will be available in all major modes and will never get in the way of anything.
You can remove the global definition of a key with
global-unset-key. This makes the key undefined; if you
type it, Emacs will just beep. Similarly, local-unset-key makes
a key undefined in the current major mode keymap, which makes the global
definition (or lack of one) come back into effect in that major mode.
If you have redefined (or undefined) a key and you subsequently wish to retract the change, undefining the key will not do the job—you need to redefine the key with its standard definition. To find the name of the standard definition of a key, go to a Fundamental mode buffer and use C-h c. The documentation of keys in this manual also lists their command names.
If you want to prevent yourself from invoking a command by mistake, it is better to disable the command than to undefine the key. A disabled command is less work to invoke when you really want to. See Disabling.
If you have a set of key bindings that you like to use all the time, you can specify them in your .emacs file by using their Lisp syntax. (See Init File.)
The simplest method for doing this works for ASCII characters and
Meta-modified ASCII characters only. This method uses a string to
represent the key sequence you want to rebind. For example, here's how
to bind C-z to shell:
(global-set-key "\C-z" 'shell)
This example uses a string constant containing one character,
C-z. (‘\C-’ is string syntax for a control character.) The
single-quote before the command name, shell, marks it as a
constant symbol rather than a variable. If you omit the quote, Emacs
would try to evaluate shell immediately as a variable. This
probably causes an error; it certainly isn't what you want.
Here is another example that binds the key sequence C-x M-l:
(global-set-key "\C-x\M-l" 'make-symbolic-link)
To put <TAB>, <RET>, <ESC>, or <DEL> in the string, you can use the Emacs Lisp escape sequences, ‘\t’, ‘\r’, ‘\e’, and ‘\d’. Here is an example which binds C-x <TAB>:
(global-set-key "\C-x\t" 'indent-rigidly)
These examples show how to write some other special ASCII characters in strings for key bindings:
(global-set-key "\r" 'newline) ;; <RET>
(global-set-key "\d" 'delete-backward-char) ;; <DEL>
(global-set-key "\C-x\e\e" 'repeat-complex-command) ;; <ESC>
When the key sequence includes function keys or mouse button events,
or non-ASCII characters such as C-= or H-a, you must use
the more general method of rebinding, which uses a vector to specify the
key sequence.
The way to write a vector in Emacs Lisp is with square brackets around the vector elements. Use spaces to separate the elements. If an element is a symbol, simply write the symbol's name—no other delimiters or punctuation are needed. If a vector element is a character, write it as a Lisp character constant: ‘?’ followed by the character as it would appear in a string.
Here are examples of using vectors to rebind C-= (a control character not in ASCII), C-M-= (not in ASCII because C-= is not), H-a (a Hyper character; ASCII doesn't have Hyper at all), <F7> (a function key), and C-Mouse-1 (a keyboard-modified mouse button):
(global-set-key [?\C-=] 'make-symbolic-link)
(global-set-key [?\M-\C-=] 'make-symbolic-link)
(global-set-key [?\H-a] 'make-symbolic-link)
(global-set-key [f7] 'make-symbolic-link)
(global-set-key [C-mouse-1] 'make-symbolic-link)
You can use a vector for the simple cases too. Here's how to rewrite the first six examples above to use vectors:
(global-set-key [?\C-z] 'shell)
(global-set-key [?\C-x ?l] 'make-symbolic-link)
(global-set-key [?\C-x ?\t] 'indent-rigidly)
(global-set-key [?\r] 'newline)
(global-set-key [?\d] 'delete-backward-char)
(global-set-key [?\C-x ?\e ?\e] 'repeat-complex-command)
As you see, you represent a multi-character key sequence with a vector by listing all of the characters in order within the square brackets that delimit the vector.
Language and coding systems can cause problems with key bindings for non-ASCII characters. See Non-ASCII Rebinding.
Key sequences can contain function keys as well as ordinary characters. Just as Lisp characters (actually integers) represent keyboard characters, Lisp symbols represent function keys. If the function key has a word as its label, then that word is also the name of the corresponding Lisp symbol. Here are the conventional Lisp names for common function keys:
left, up, right, downbegin, end, home, next, priorselect, print, execute, backtabinsert, undo, redo, clearlineinsertline, deleteline, insertchar, deletecharf1, f2, ... f35kp-add, kp-subtract, kp-multiply, kp-dividekp-backtab, kp-space, kp-tab, kp-enterkp-separator, kp-decimal, kp-equalkp-0, kp-1, ... kp-9kp-f1, kp-f2, kp-f3, kp-f4These names are conventional, but some systems (especially when using X) may use different names. To make certain what symbol is used for a given function key on your terminal, type C-h c followed by that key.
A key sequence which contains function key symbols (or anything but
ASCII characters) must be a vector rather than a string.
Thus, to bind function key ‘f1’ to the command rmail,
write the following:
(global-set-key [f1] 'rmail)
To bind the right-arrow key to the command forward-char, you can
use this expression:
(global-set-key [right] 'forward-char)
This uses the Lisp syntax for a vector containing the symbol
right. (This binding is present in Emacs by default.)
See Init Rebinding, for more information about using vectors for rebinding.
You can mix function keys and characters in a key sequence. This
example binds C-x <NEXT> to the command forward-page.
(global-set-key [?\C-x next] 'forward-page)
where ?\C-x is the Lisp character constant for the character
C-x. The vector element next is a symbol and therefore
does not take a question mark.
You can use the modifier keys <CTRL>, <META>, <HYPER>, <SUPER>, <ALT> and <SHIFT> with function keys. To represent these modifiers, add the strings ‘C-’, ‘M-’, ‘H-’, ‘s-’, ‘A-’ and ‘S-’ at the front of the symbol name. Thus, here is how to make Hyper-Meta-<RIGHT> move forward a word:
(global-set-key [H-M-right] 'forward-word)
Many keyboards have a “numeric keypad” on the right hand side.
The numeric keys in the keypad double up as cursor motion keys,
toggled by a key labeled ‘Num Lock’. By default, Emacs
translates these keys to the corresponding keys in the main keyboard.
For example, when ‘Num Lock’ is on, the key labeled ‘8’ on
the numeric keypad produces kp-8, which is translated to
8; when ‘Num Lock’ is off, the same key produces
kp-up, which is translated to <UP>. If you rebind a key
such as 8 or <UP>, it affects the equivalent keypad key too.
However, if you rebind a ‘kp-’ key directly, that won't affect
its non-keypad equivalent.
Emacs provides a convenient method for binding the numeric keypad
keys, using the variables keypad-setup,
keypad-numlock-setup, keypad-shifted-setup, and
keypad-numlock-shifted-setup. These can be found in the
‘keyboard’ customization group (see Easy Customization). You
can rebind the keys to perform other tasks, such as issuing numeric
prefix arguments.
<TAB>, <RET>, <BS>, <LFD>, <ESC> and <DEL> started out as names for certain ASCII control characters, used so often that they have special keys of their own. For instance, <TAB> was another name for C-i. Later, users found it convenient to distinguish in Emacs between these keys and the “same” control characters typed with the <CTRL> key. Therefore, on most modern terminals, they are no longer the same, and <TAB> is distinguishable from C-i.
Emacs can distinguish these two kinds of input if the keyboard does.
It treats the “special” keys as function keys named tab,
return, backspace, linefeed, escape, and
delete. These function keys translate automatically into the
corresponding ASCII characters if they have no
bindings of their own. As a result, neither users nor Lisp programs
need to pay attention to the distinction unless they care to.
If you do not want to distinguish between (for example) <TAB> and
C-i, make just one binding, for the ASCII character <TAB>
(octal code 011). If you do want to distinguish, make one binding for
this ASCII character, and another for the “function key” tab.
With an ordinary ASCII terminal, there is no way to distinguish between <TAB> and C-i (and likewise for other such pairs), because the terminal sends the same character in both cases.
If your keyboard has keys that send non-ASCII characters, such as accented letters, rebinding these keys must be done by using a vector like this21:
(global-set-key [?char] 'some-function)
Type C-q followed by the key you want to bind, to insert char.
Since this puts a non-ASCII character in the .emacs, you should specify a coding system for that file that supports the character in question. See Init Syntax.
Warning: if you change the keyboard encoding, or change between multibyte and unibyte mode, or anything that would alter which code C-q would insert for that character, you'll need to edit the Lisp expression accordingly, to use the character code generated by C-q in the new mode.
Emacs uses Lisp symbols to designate mouse buttons, too. The ordinary mouse events in Emacs are click events; these happen when you press a button and release it without moving the mouse. You can also get drag events, when you move the mouse while holding the button down. Drag events happen when you finally let go of the button.
The symbols for basic click events are mouse-1 for the leftmost
button, mouse-2 for the next, and so on. Here is how you can
redefine the second mouse button to split the current window:
(global-set-key [mouse-2] 'split-window-vertically)
The symbols for drag events are similar, but have the prefix
‘drag-’ before the word ‘mouse’. For example, dragging the
first button generates a drag-mouse-1 event.
You can also define bindings for events that occur when a mouse button is pressed down. These events start with ‘down-’ instead of ‘drag-’. Such events are generated only if they have key bindings. When you get a button-down event, a corresponding click or drag event will always follow.
If you wish, you can distinguish single, double, and triple clicks. A
double click means clicking a mouse button twice in approximately the
same place. The first click generates an ordinary click event. The
second click, if it comes soon enough, generates a double-click event
instead. The event type for a double-click event starts with
‘double-’: for example, double-mouse-3.
This means that you can give a special meaning to the second click at the same place, but it must act on the assumption that the ordinary single click definition has run when the first click was received.
This constrains what you can do with double clicks, but user interface designers say that this constraint ought to be followed in any case. A double click should do something similar to the single click, only “more so.” The command for the double-click event should perform the extra work for the double click.
If a double-click event has no binding, it changes to the corresponding single-click event. Thus, if you don't define a particular double click specially, it executes the single-click command twice.
Emacs also supports triple-click events whose names start with ‘triple-’. Emacs does not distinguish quadruple clicks as event types; clicks beyond the third generate additional triple-click events. However, the full number of clicks is recorded in the event list, so if you know Emacs Lisp you can distinguish if you really want to (see Accessing Events). We don't recommend distinct meanings for more than three clicks, but sometimes it is useful for subsequent clicks to cycle through the same set of three meanings, so that four clicks are equivalent to one click, five are equivalent to two, and six are equivalent to three.
Emacs also records multiple presses in drag and button-down events. For example, when you press a button twice, then move the mouse while holding the button, Emacs gets a ‘double-drag-’ event. And at the moment when you press it down for the second time, Emacs gets a ‘double-down-’ event (which is ignored, like all button-down events, if it has no binding).
The variable double-click-time specifies how much time can
elapse between clicks and still allow them to be grouped as a multiple
click. Its value is in units of milliseconds. If the value is
nil, double clicks are not detected at all. If the value is
t, then there is no time limit. The default is 500.
The variable double-click-fuzz specifies how much the mouse
can move between clicks and still allow them to be grouped as a multiple
click. Its value is in units of pixels on windowed displays and in
units of 1/8 of a character cell on text-mode terminals; the default is
3.
The symbols for mouse events also indicate the status of the modifier keys, with the usual prefixes ‘C-’, ‘M-’, ‘H-’, ‘s-’, ‘A-’ and ‘S-’. These always precede ‘double-’ or ‘triple-’, which always precede ‘drag-’ or ‘down-’.
A frame includes areas that don't show text from the buffer, such as
the mode line and the scroll bar. You can tell whether a mouse button
comes from a special area of the screen by means of dummy “prefix
keys.” For example, if you click the mouse in the mode line, you get
the prefix key mode-line before the ordinary mouse-button symbol.
Thus, here is how to define the command for clicking the first button in
a mode line to run scroll-up:
(global-set-key [mode-line mouse-1] 'scroll-up)
Here is the complete list of these dummy prefix keys and their meanings:
mode-linevertical-linevertical-scroll-barmenu-barheader-lineYou can put more than one mouse button in a key sequence, but it isn't usual to do so.
Disabling a command marks the command as requiring confirmation before it can be executed. The purpose of disabling a command is to prevent beginning users from executing it by accident and being confused.
An attempt to invoke a disabled command interactively in Emacs displays a window containing the command's name, its documentation, and some instructions on what to do immediately; then Emacs asks for input saying whether to execute the command as requested, enable it and execute it, or cancel. If you decide to enable the command, you are asked whether to do this permanently or just for the current session. (Enabling permanently works by automatically editing your .emacs file.) You can also type ! to enable all commands, for the current session only.
The direct mechanism for disabling a command is to put a
non-nil disabled property on the Lisp symbol for the
command. Here is the Lisp program to do this:
(put 'delete-region 'disabled t)
If the value of the disabled property is a string, that string
is included in the message displayed when the command is used:
(put 'delete-region 'disabled
"It's better to use `kill-region' instead.\n")
You can make a command disabled either by editing the .emacs file directly or with the command M-x disable-command, which edits the .emacs file for you. Likewise, M-x enable-command edits .emacs to enable a command permanently. See Init File.
If Emacs was invoked with the -q or --no-init-file options (see Initial Options), it will not edit your ~/.emacs init file. This is because editing the init file from such a session might overwrite the lines you might have on your init file which enable and disable commands.
Whether a command is disabled is independent of what key is used to invoke it; disabling also applies if the command is invoked using M-x. Disabling a command has no effect on calling it as a function from Lisp programs.
All the Emacs commands which parse words or balance parentheses are controlled by the syntax table. The syntax table says which characters are opening delimiters, which are parts of words, which are string quotes, and so on. It does this by assigning each character to one of fifteen-odd syntax classes. In some cases it specifies some additional information also.
Each major mode has its own syntax table (though related major modes sometimes share one syntax table) which it installs in each buffer that uses the mode. The syntax table installed in the current buffer is the one that all commands use, so we call it “the” syntax table.
To display a description of the contents of the current syntax
table, type C-h s (describe-syntax). The description of
each character includes both the string you would have to give to
modify-syntax-entry to set up that character's current syntax,
starting with the character which designates its syntax class, plus
some English text to explain its meaning.
A syntax table is actually a Lisp object, a char-table, whose elements are cons cells. For full information on the syntax table, see Syntax Tables.
When Emacs is started, it normally loads a Lisp program from the file .emacs or .emacs.el in your home directory. We call this file your init file because it specifies how to initialize Emacs for you. You can use the command line switch ‘-q’ to prevent loading your init file, and ‘-u’ (or ‘--user’) to specify a different user's init file (see Initial Options).
You can also use ~/.emacs.d/init.el as the init file. Emacs tries this if it cannot find ~/.emacs or ~/.emacs.el.
There can also be a default init file, which is the library
named default.el, found via the standard search path for
libraries. The Emacs distribution contains no such library; your site
may create one for local customizations. If this library exists, it is
loaded whenever you start Emacs (except when you specify ‘-q’).
But your init file, if any, is loaded first; if it sets
inhibit-default-init non-nil, then default is not
loaded.
Your site may also have a site startup file; this is named site-start.el, if it exists. Like default.el, Emacs finds this file via the standard search path for Lisp libraries. Emacs loads this library before it loads your init file. To inhibit loading of this library, use the option ‘--no-site-file’. See Initial Options. We recommend against using site-start.el for changes that some users may not like. It is better to put them in default.el, so that users can more easily override them.
You can place default.el and site-start.el in any of
the directories which Emacs searches for Lisp libraries. The variable
load-path (see Lisp Libraries) specifies these directories.
Many sites put these files in the site-lisp subdirectory of the
Emacs installation directory, typically
/usr/local/share/emacs/site-lisp.
If you have a large amount of code in your .emacs file, you should rename it to ~/.emacs.el, and byte-compile it. See Byte Compilation, for more information about compiling Emacs Lisp programs.
If you are going to write actual Emacs Lisp programs that go beyond minor customization, you should read the Emacs Lisp Reference Manual.
The .emacs file contains one or more Lisp function call
expressions. Each of these consists of a function name followed by
arguments, all surrounded by parentheses. For example, (setq
fill-column 60) calls the function setq to set the variable
fill-column (see Filling) to 60.
You can set any Lisp variable with setq, but with certain
variables setq won't do what you probably want in the
.emacs file. Some variables automatically become buffer-local
when set with setq; what you want in .emacs is to set
the default value, using setq-default. Some customizable minor
mode variables do special things to enable the mode when you set them
with Customize, but ordinary setq won't do that; to enable the
mode in your .emacs file, call the minor mode command. The
following section has examples of both of these methods.
The second argument to setq is an expression for the new
value of the variable. This can be a constant, a variable, or a
function call expression. In .emacs, constants are used most
of the time. They can be:
In a string, you can include newlines and special characters literally. But often it is cleaner to use backslash sequences for them: ‘\n’ for newline, ‘\b’ for backspace, ‘\r’ for carriage return, ‘\t’ for tab, ‘\f’ for formfeed (control-L), ‘\e’ for escape, ‘\\’ for a backslash, ‘\"’ for a double-quote, or ‘\ooo’ for the character whose octal code is ooo. Backslash and double-quote are the only characters for which backslash sequences are mandatory.
‘\C-’ can be used as a prefix for a control character, as in ‘\C-s’ for ASCII control-S, and ‘\M-’ can be used as a prefix for a Meta character, as in ‘\M-a’ for Meta-A or ‘\M-\C-a’ for Control-Meta-A.
If you want to include non-ASCII characters in strings in your init
file, you should consider putting a ‘-*-coding: coding-system-*-’ tag on the first line which states the coding
system used to save your .emacs, as explained in Recognize Coding. This is because the defaults for decoding non-ASCII text might
not yet be set up by the time Emacs reads those parts of your init file
which use such strings, possibly leading Emacs to decode those strings
incorrectly.
?x, ?\n, ?\", ?\). Note that
strings and characters are not interchangeable in Lisp; some contexts
require one and some contexts require the other.
See Non-ASCII Rebinding, for information about binding commands to
keys which send non-ASCII characters.
t stands for `true'.
nil stands for `false'.
') followed by the Lisp object you want.
Here are some examples of doing certain commonly desired things with Lisp expressions:
(setq c-tab-always-indent nil)
Here we have a variable whose value is normally t for `true'
and the alternative is nil for `false'.
(setq-default case-fold-search nil)
This sets the default value, which is effective in all buffers that do
not have local values for the variable. Setting case-fold-search
with setq affects only the current buffer's local value, which
is not what you probably want to do in an init file.
(setq user-mail-address "coon@yoyodyne.com")
Various Emacs packages that need your own email address use the value of
user-mail-address.
(setq default-major-mode 'text-mode)
Note that text-mode is used because it is the command for
entering Text mode. The single-quote before it makes the symbol a
constant; otherwise, text-mode would be treated as a variable
name.
(set-language-environment "Latin-1")
(line-number-mode 0)
(add-hook 'text-mode-hook
'(lambda () (auto-fill-mode 1)))
This shows how to add a hook function to a normal hook variable
(see Hooks). The function we supply is a list starting with
lambda, with a single-quote in front of it to make it a list
constant rather than an expression.
It's beyond the scope of this manual to explain Lisp functions, but for
this example it is enough to know that the effect is to execute
(auto-fill-mode 1) when Text mode is entered. You can replace
that with any other expression that you like, or with several
expressions in a row.
Emacs comes with a function named turn-on-auto-fill whose
definition is (lambda () (auto-fill-mode 1)). Thus, a simpler
way to write the above example is as follows:
(add-hook 'text-mode-hook 'turn-on-auto-fill)
(load "foo")
When the argument to load is a relative file name, not starting
with ‘/’ or ‘~’, load searches the directories in
load-path (see Lisp Libraries).
(load "~/foo.elc")
Here an absolute file name is used, so no searching is done.
myfunction
by loading a Lisp library named mypackage (i.e. a file
mypackage.elc or mypackage.el):
(autoload 'myfunction "mypackage" "Do what I say." t)
Here the string "Do what I say." is the function's
documentation string. You specify it in the autoload
definition so it will be available for help commands even when the
package is not loaded. The last argument, t, indicates that
this function is interactive; that is, it can be invoked interactively
by typing M-x myfunction <RET> or by binding it to a key.
If the function is not interactive, omit the t or use
nil.
make-symbolic-link
(see Init Rebinding).
(global-set-key "\C-xl" 'make-symbolic-link)
or
(define-key global-map "\C-xl" 'make-symbolic-link)
Note once again the single-quote used to refer to the symbol
make-symbolic-link instead of its value as a variable.
(define-key lisp-mode-map "\C-xl" 'make-symbolic-link)
next-line in Fundamental mode
so that they run forward-line instead.
(substitute-key-definition 'next-line 'forward-line
global-map)
(global-unset-key "\C-x\C-v")
One reason to undefine a key is so that you can make it a prefix. Simply defining C-x C-v anything will make C-x C-v a prefix, but C-x C-v must first be freed of its usual non-prefix definition.
(modify-syntax-entry ?\$ "." text-mode-syntax-table)
narrow-to-region without confirmation.
(put 'narrow-to-region 'disabled nil)
Users typically want Emacs to behave the same on all systems, so the same init file is right for all platforms. However, sometimes it happens that a function you use for customizing Emacs is not available on some platforms or in older Emacs versions. To deal with that situation, put the customization inside a conditional that tests whether the function or facility is available, like this:
(if (fboundp 'blink-cursor-mode)
(blink-cursor-mode 0))
(if (boundp 'coding-category-utf-8)
(set-coding-priority '(coding-category-utf-8)))
You can also simply disregard the errors that occur if the function is not defined.
(condition case ()
(set-face-background 'region "grey75")
(error nil))
A setq on a variable which does not exist is generally
harmless, so those do not need a conditional.
Each terminal type can have a Lisp library to be loaded into Emacs when
it is run on that type of terminal. For a terminal type named
termtype, the library is called term/termtype and it is
found by searching the directories load-path as usual and trying the
suffixes ‘.elc’ and ‘.el’. Normally it appears in the
subdirectory term of the directory where most Emacs libraries are
kept.
The usual purpose of the terminal-specific library is to map the
escape sequences used by the terminal's function keys onto more
meaningful names, using function-key-map. See the file
term/lk201.el for an example of how this is done. Many function
keys are mapped automatically according to the information in the
Termcap data base; the terminal-specific library needs to map only the
function keys that Termcap does not specify.
When the terminal type contains a hyphen, only the part of the name
before the first hyphen is significant in choosing the library name.
Thus, terminal types ‘aaa-48’ and ‘aaa-30-rv’ both use
the library term/aaa. The code in the library can use
(getenv "TERM") to find the full terminal type name.
The library's name is constructed by concatenating the value of the
variable term-file-prefix and the terminal type. Your .emacs
file can prevent the loading of the terminal-specific library by setting
term-file-prefix to nil.
Emacs runs the hook term-setup-hook at the end of
initialization, after both your .emacs file and any
terminal-specific library have been read in. Add hook functions to this
hook if you wish to override part of any of the terminal-specific
libraries and to define initializations for terminals that do not have a
library. See Hooks.
Normally Emacs uses the environment variable HOME to find .emacs; that's what ‘~’ means in a file name. If .emacs is not found inside ~/ (nor .emacs.el), Emacs looks for ~/.emacs.d/init.el (which, like ~/.emacs.el, can be byte-compiled).
However, if you run Emacs from a shell started by su, Emacs
tries to find your own .emacs, not that of the user you are
currently pretending to be. The idea is that you should get your own
editor customizations even if you are running as the super user.
More precisely, Emacs first determines which user's init file to use. It gets the user name from the environment variables LOGNAME and USER; if neither of those exists, it uses effective user-ID. If that user name matches the real user-ID, then Emacs uses HOME; otherwise, it looks up the home directory corresponding to that user name in the system's data base of users.
abort-recursive-edit).
keyboard-escape-quit).
undo).
There are two ways of canceling commands which are not finished executing: quitting with C-g, and aborting with C-] or M-x top-level. Quitting cancels a partially typed command or one which is already running. Aborting exits a recursive editing level and cancels the command that invoked the recursive edit. (See Recursive Edit.)
Quitting with C-g is used for getting rid of a partially typed command, or a numeric argument that you don't want. It also stops a running command in the middle in a relatively safe way, so you can use it if you accidentally give a command which takes a long time. In particular, it is safe to quit out of killing; either your text will all still be in the buffer, or it will all be in the kill ring (or maybe both). Quitting an incremental search does special things documented under searching; in general, it may take two successive C-g characters to get out of a search (see Incremental Search).
On MS-DOS, the character C-<BREAK> serves as a quit character like C-g. The reason is that it is not feasible, on MS-DOS, to recognize C-g while a command is running, between interactions with the user. By contrast, it is feasible to recognize C-<BREAK> at all times. See MS-DOS Keyboard.
C-g works by setting the variable quit-flag to t
the instant C-g is typed; Emacs Lisp checks this variable
frequently and quits if it is non-nil. C-g is only
actually executed as a command if you type it while Emacs is waiting for
input. In that case, the command it runs is keyboard-quit.
On a text terminal, if you quit with C-g a second time before the first C-g is recognized, you activate the “emergency escape” feature and return to the shell. See Emergency Escape.
There may be times when you cannot quit. When Emacs is waiting for the operating system to do something, quitting is impossible unless special pains are taken for the particular system call within Emacs where the waiting occurs. We have done this for the system calls that users are likely to want to quit from, but it's possible you will find another. In one very common case—waiting for file input or output using NFS—Emacs itself knows how to quit, but many NFS implementations simply do not allow user programs to stop waiting for NFS when the NFS server is hung.
Aborting with C-] (abort-recursive-edit) is used to get
out of a recursive editing level and cancel the command which invoked
it. Quitting with C-g does not do this, and could not do this,
because it is used to cancel a partially typed command within the
recursive editing level. Both operations are useful. For example, if
you are in a recursive edit and type C-u 8 to enter a numeric
argument, you can cancel that argument with C-g and remain in the
recursive edit.
The command <ESC> <ESC> <ESC>
(keyboard-escape-quit) can either quit or abort. This key was
defined because <ESC> is used to “get out” in many PC programs.
It can cancel a prefix argument, clear a selected region, or get out of
a Query Replace, like C-g. It can get out of the minibuffer or a
recursive edit, like C-]. It can also get out of splitting the
frame into multiple windows, like C-x 1. One thing it cannot do,
however, is stop a command that is running. That's because it executes
as an ordinary command, and Emacs doesn't notice it until it is ready
for a command.
The command M-x top-level is equivalent to “enough” C-] commands to get you out of all the levels of recursive edits that you are in. C-] gets you out one level at a time, but M-x top-level goes out all levels at once. Both C-] and M-x top-level are like all other commands, and unlike C-g, in that they take effect only when Emacs is ready for a command. C-] is an ordinary key and has its meaning only because of its binding in the keymap. See Recursive Edit.
C-x u (undo) is not strictly speaking a way of canceling
a command, but you can think of it as canceling a command that already
finished executing. See Undo, for more information
about the undo facility.
This section describes various conditions in which Emacs fails to work normally, and how to recognize them and correct them. For a list of additional problems you might encounter, see Bugs and problems, and the file etc/PROBLEMS in the Emacs distribution. Type C-h C-f to read the FAQ; type C-h C-e to read the PROBLEMS file.
Every keyboard has a large key, a little ways above the <RET> or <ENTER> key, which you normally use outside Emacs to erase the last character that you typed. We call this key the usual erasure key. In Emacs, it is supposed to be equivalent to <DEL>, and when Emacs is properly configured for your terminal, it translates that key into the character <DEL>.
When Emacs starts up using a window system, it determines automatically which key should be <DEL>. In some unusual cases Emacs gets the wrong information from the system. If the usual erasure key deletes forwards instead of backwards, that is probably what happened—Emacs ought to be treating the <DELETE> key as <DEL>, but it isn't.
With a window system, if the usual erasure key is labeled <BACKSPACE> and there is a <DELETE> key elsewhere, but the <DELETE> key deletes backward instead of forward, that too suggests Emacs got the wrong information—but in the opposite sense. It ought to be treating the <BACKSPACE> key as <DEL>, and treating <DELETE> differently, but it isn't.
On a text-only terminal, if you find the usual erasure key prompts for a Help command, like Control-h, instead of deleting a character, it means that key is actually sending the <BS> character. Emacs ought to be treating <BS> as <DEL>, but it isn't.
In all of those cases, the immediate remedy is the same: use the command M-x normal-erase-is-backspace-mode. This toggles between the two modes that Emacs supports for handling <DEL>, so if Emacs starts in the wrong mode, it should switch to the right mode. On a text-only terminal, if you want to ask for help when <BS> is treated as <DEL>, use <F1>; C-? may also work, if it sends character code 127.
To fix the problem automatically for every Emacs session, you can put one of the following lines into your .emacs file (see Init File). For the first case above, where <DELETE> deletes forwards instead of backwards, use this line to make <DELETE> act as <DEL> (resulting in behavior compatible with Emacs 20 and previous versions):
(normal-erase-is-backspace-mode 0)
For the other two cases, where <BACKSPACE> ought to act as <DEL>, use this line:
(normal-erase-is-backspace-mode 1)
Another way to fix the problem for every Emacs session is to
customize the variable normal-erase-is-backspace: the value
t specifies the mode where <BS> or <BACKSPACE> is
<DEL>, and nil specifies the other mode. See Easy Customization.
With a window system, it can also happen that the usual erasure key
is labeled <BACKSPACE>, there is a <DELETE> key elsewhere, and
both keys delete forward. This probably means that someone has
redefined your <BACKSPACE> key as a <DELETE> key. With X,
this is typically done with a command to the xmodmap program
when you start the server or log in. The most likely motive for this
customization was to support old versions of Emacs, so we recommend
you simply remove it now.
Recursive editing levels are important and useful features of Emacs, but they can seem like malfunctions to the user who does not understand them.
If the mode line has square brackets ‘[...]’ around the parentheses that contain the names of the major and minor modes, you have entered a recursive editing level. If you did not do this on purpose, or if you don't understand what that means, you should just get out of the recursive editing level. To do so, type M-x top-level. This is called getting back to top level. See Recursive Edit.
If the text on a text terminal looks wrong, the first thing to do is see whether it is wrong in the buffer. Type C-l to redisplay the entire screen. If the screen appears correct after this, the problem was entirely in the previous screen update. (Otherwise, see the following section.)
Display updating problems often result from an incorrect termcap entry for the terminal you are using. The file etc/TERMS in the Emacs distribution gives the fixes for known problems of this sort. INSTALL contains general advice for these problems in one of its sections. Very likely there is simply insufficient padding for certain display operations. To investigate the possibility that you have this sort of problem, try Emacs on another terminal made by a different manufacturer. If problems happen frequently on one kind of terminal but not another kind, it is likely to be a bad termcap entry, though it could also be due to a bug in Emacs that appears for terminals that have or that lack specific features.
If C-l shows that the text is wrong, try undoing the changes to it using C-x u until it gets back to a state you consider correct. Also try C-h l to find out what command you typed to produce the observed results.
If a large portion of text appears to be missing at the beginning or end of the buffer, check for the word ‘Narrow’ in the mode line. If it appears, the text you don't see is probably still present, but temporarily off-limits. To make it accessible again, type C-x n w. See Narrowing.
If Emacs spontaneously displays ‘I-search:’ at the bottom of the screen, it means that the terminal is sending C-s and C-q according to the poorly designed xon/xoff “flow control” protocol.
If this happens to you, your best recourse is to put the terminal in a
mode where it will not use flow control, or give it so much padding that
it will never send a C-s. (One way to increase the amount of
padding is to set the variable baud-rate to a larger value. Its
value is the terminal output speed, measured in the conventional units
of baud.)
If you don't succeed in turning off flow control, the next best thing
is to tell Emacs to cope with it. To do this, call the function
enable-flow-control.
Typically there are particular terminal types with which you must use
flow control. You can conveniently ask for flow control on those
terminal types only, using enable-flow-control-on. For example,
if you find you must use flow control on VT-100 and H19 terminals, put
the following in your .emacs file:
(enable-flow-control-on "vt100" "h19")
When flow control is enabled, you must type C-\ to get the effect of a C-s, and type C-^ to get the effect of a C-q.
If you get the error message ‘Virtual memory exceeded’, save your modified buffers with C-x s. This method of saving them has the smallest need for additional memory. Emacs keeps a reserve of memory which it makes available when this error happens; that should be enough to enable C-x s to complete its work. When the reserve has been used, ‘!MEM FULL!’ appears at the beginning of the mode line, indicating there is no more reserve.
Once you have saved your modified buffers, you can exit this Emacs session and start another, or you can use M-x kill-some-buffers to free space in the current Emacs job. If this frees up sufficient space, Emacs will refill its memory reserve, and ‘!MEM FULL!’ will disappear from the mode line. That means you can safely go on editing in the same Emacs session.
Do not use M-x buffer-menu to save or kill buffers when you run out of memory, because the buffer menu needs a fair amount of memory itself, and the reserve supply may not be enough.
If Emacs or the computer crashes, you can recover the files you were editing at the time of the crash from their auto-save files. To do this, start Emacs again and type the command M-x recover-session.
This command initially displays a buffer which lists interrupted session files, each with its date. You must choose which session to recover from. Typically the one you want is the most recent one. Move point to the one you choose, and type C-c C-c.
Then recover-session asks about each of the files that you were
editing during that session; it asks whether to recover that file. If
you answer y for a file, it shows the dates of that file and its
auto-save file, then asks once again whether to recover that file. For
the second question, you must confirm with yes. If you do, Emacs
visits the file but gets the text from the auto-save file.
When recover-session is done, the files you've chosen to
recover are present in Emacs buffers. You should then save them. Only
this—saving them—updates the files themselves.
As a last resort, if you had buffers with content which were not associated with any files, or if the autosave was not recent enough to have recorded important changes, you can use the etc/emacs-buffer.gdb script with GDB (the GNU Debugger) to retrieve them from a core dump–provided that a core dump was saved, and that the Emacs executable was not stripped of its debugging symbols.
To use this script, run gdb with the file name of your Emacs
executable and the file name of the core dump, e.g. ‘gdb
/usr/bin/emacs core.emacs’. At the (gdb) prompt, load the
recovery script: ‘source /usr/src/emacs/etc/emacs-buffer.gdb’.
Then type the command ybuffer-list to see which buffers are
available. For each buffer, it lists a buffer number. To save a
buffer, use ysave-buffer; you specify the buffer number, and
the file name to write that buffer into. You should use a file name
which does not already exist; if the file does exist, the script does
not make a backup of its old contents.
Because at times there have been bugs causing Emacs to loop without
checking quit-flag, a special feature causes Emacs to be suspended
immediately if you type a second C-g while the flag is already set,
so you can always get out of GNU Emacs. Normally Emacs recognizes and
clears quit-flag (and quits!) quickly enough to prevent this from
happening. (On MS-DOS and compatible systems, type C-<BREAK>
twice.)
When you resume Emacs after a suspension caused by multiple C-g, it asks two questions before going back to what it had been doing:
Auto-save? (y or n)
Abort (and dump core)? (y or n)
Answer each one with y or n followed by <RET>.
Saying y to ‘Auto-save?’ causes immediate auto-saving of all modified buffers in which auto-saving is enabled.
Saying y to ‘Abort (and dump core)?’ causes an illegal instruction to be
executed, dumping core. This is to enable a wizard to figure out why Emacs
was failing to quit in the first place. Execution does not continue
after a core dump. If you answer n, execution does continue. With
luck, GNU Emacs will ultimately check quit-flag and quit normally.
If not, and you type another C-g, it is suspended again.
If Emacs is not really hung, just slow, you may invoke the double C-g feature without really meaning to. Then just resume and answer n to both questions, and you will arrive at your former state. Presumably the quit you requested will happen soon.
The double C-g feature is turned off when Emacs is running under the X Window System, since you can use the window manager to kill Emacs or to create another window and run another program.
On MS-DOS and compatible systems, the emergency escape feature is sometimes unavailable, even if you press C-<BREAK> twice, when some system call (MS-DOS or BIOS) hangs, or when Emacs is stuck in a very tight endless loop (in C code, not in Lisp code).
If using Emacs (or something else) becomes terribly frustrating and none of the techniques described above solve the problem, Emacs can still help you.
First, if the Emacs you are using is not responding to commands, type C-g C-g to get out of it and then start a new one.
Second, type M-x doctor <RET>.
The doctor will help you feel better. Each time you say something to the doctor, you must end it by typing <RET> <RET>. This lets the doctor know you are finished.
Sometimes you will encounter a bug in Emacs. Although we cannot promise we can or will fix the bug, and we might not even agree that it is a bug, we want to hear about problems you encounter. Often we agree they are bugs and want to fix them.
To make it possible for us to fix a bug, you must report it. In order to do so effectively, you must know when and how to do it.
Before reporting a bug, it is a good idea to see if it is already known. You can find the list of known problems in the file etc/PROBLEMS in the Emacs distribution; type C-h C-e to read it. Some additional user-level problems can be found in Bugs and problems. Looking up your problem in these two documents might provide you with a solution or a work-around, or give you additional information about related issues.
If Emacs executes an illegal instruction, or dies with an operating system error message that indicates a problem in the program (as opposed to something like “disk full”), then it is certainly a bug.
If Emacs updates the display in a way that does not correspond to what is in the buffer, then it is certainly a bug. If a command seems to do the wrong thing but the problem corrects itself if you type C-l, it is a case of incorrect display updating.
Taking forever to complete a command can be a bug, but you must make certain that it was really Emacs's fault. Some commands simply take a long time. Type C-g (C-<BREAK> on MS-DOS) and then C-h l to see whether the input Emacs received was what you intended to type; if the input was such that you know it should have been processed quickly, report a bug. If you don't know whether the command should take a long time, find out by looking in the manual or by asking for assistance.
If a command you are familiar with causes an Emacs error message in a case where its usual definition ought to be reasonable, it is probably a bug.
If a command does the wrong thing, that is a bug. But be sure you know for certain what it ought to have done. If you aren't familiar with the command, or don't know for certain how the command is supposed to work, then it might actually be working right. Rather than jumping to conclusions, show the problem to someone who knows for certain.
Finally, a command's intended definition may not be the best possible definition for editing with. This is a very important sort of problem, but it is also a matter of judgment. Also, it is easy to come to such a conclusion out of ignorance of some of the existing features. It is probably best not to complain about such a problem until you have checked the documentation in the usual ways, feel confident that you understand it, and know for certain that what you want is not available. If you are not sure what the command is supposed to do after a careful reading of the manual, check the index and glossary for any terms that may be unclear.
If after careful rereading of the manual you still do not understand what the command should do, that indicates a bug in the manual, which you should report. The manual's job is to make everything clear to people who are not Emacs experts—including you. It is just as important to report documentation bugs as program bugs.
If the on-line documentation string of a function or variable disagrees with the manual, one of them must be wrong; that is a bug.
When you decide that there is a bug, it is important to report it and to report it in a way which is useful. What is most useful is an exact description of what commands you type, starting with the shell command to run Emacs, until the problem happens.
The most important principle in reporting a bug is to report facts. Hypotheses and verbal descriptions are no substitute for the detailed raw data. Reporting the facts is straightforward, but many people strain to posit explanations and report them instead of the facts. If the explanations are based on guesses about how Emacs is implemented, they will be useless; meanwhile, lacking the facts, we will have no real information about the bug.
For example, suppose that you type C-x C-f /glorp/baz.ugh <RET>, visiting a file which (you know) happens to be rather large, and Emacs displayed ‘I feel pretty today’. The best way to report the bug is with a sentence like the preceding one, because it gives all the facts.
A bad way would be to assume that the problem is due to the size of the file and say, “I visited a large file, and Emacs displayed ‘I feel pretty today’.” This is what we mean by “guessing explanations.” The problem is just as likely to be due to the fact that there is a ‘z’ in the file name. If this is so, then when we got your report, we would try out the problem with some “large file,” probably with no ‘z’ in its name, and not see any problem. There is no way in the world that we could guess that we should try visiting a file with a ‘z’ in its name.
Alternatively, the problem might be due to the fact that the file starts with exactly 25 spaces. For this reason, you should make sure that you inform us of the exact contents of any file that is needed to reproduce the bug. What if the problem only occurs when you have typed the C-x C-a command previously? This is why we ask you to give the exact sequence of characters you typed since starting the Emacs session.
You should not even say “visit a file” instead of C-x C-f unless you know that it makes no difference which visiting command is used. Similarly, rather than saying “if I have three characters on the line,” say “after I type <RET> A B C <RET> C-p,” if that is the way you entered the text.
So please don't guess any explanations when you report a bug. If you want to actually debug the problem, and report explanations that are more than guesses, that is useful—but please include the facts as well.
The best way to send a bug report is to mail it electronically to the Emacs maintainers at bug-gnu-emacs@gnu.org, or to emacs-pretest-bug@gnu.org if you are pretesting an Emacs beta release. (If you want to suggest a change as an improvement, use the same address.)
If you'd like to read the bug reports, you can find them on the newsgroup ‘gnu.emacs.bug’; keep in mind, however, that as a spectator you should not criticize anything about what you see there. The purpose of bug reports is to give information to the Emacs maintainers. Spectators are welcome only as long as they do not interfere with this. In particular, some bug reports contain fairly large amounts of data; spectators should not complain about this.
Please do not post bug reports using netnews; mail is more reliable than netnews about reporting your correct address, which we may need in order to ask you for more information. If your data is more than 500,000 bytes, please don't include it directly in the bug report; instead, offer to send it on request, or make it available by ftp and say where.
If you can't send electronic mail, then mail the bug report on paper or machine-readable media to this address:
GNU Emacs Bugs Free Software Foundation 51 Franklin Street, Fifth Floor Boston, MA 02110-1301 USA
We do not promise to fix the bug; but if the bug is serious, or ugly, or easy to fix, chances are we will want to.
A convenient way to send a bug report for Emacs is to use the command M-x report-emacs-bug. This sets up a mail buffer (see Sending Mail) and automatically inserts some of the essential information. However, it cannot supply all the necessary information; you should still read and follow the guidelines below, so you can enter the other crucial information by hand before you send the message.
To enable maintainers to investigate a bug, your report should include all these things:
You can get the version number by typing M-x emacs-version <RET>. If that command does not work, you probably have something other than GNU Emacs, so you will have to report the bug somewhere else.
configure command when Emacs was
installed.
Be precise about these changes. A description in English is not enough—send a context diff for them.
Adding files of your own, or porting to another machine, is a modification of the source.
If you can tell us a way to cause the problem without visiting any files, please do so. This makes it much easier to debug. If you do need files, make sure you arrange for us to see their exact contents. For example, it can often matter whether there are spaces at the ends of lines, or a newline after the last line in the buffer (nothing ought to care whether the last line is terminated, but try telling the bugs that).
The easy way to record the input to Emacs precisely is to write a dribble file. To start the file, execute the Lisp expression
(open-dribble-file "~/dribble")
using M-: or from the ‘*scratch*’ buffer just after starting Emacs. From then on, Emacs copies all your input to the specified dribble file until the Emacs process is killed.
The way to collect the terminal output is to execute the Lisp expression
(open-termscript "~/termscript")
using M-: or from the ‘*scratch*’ buffer just after starting Emacs. From then on, Emacs copies all terminal output to the specified termscript file as well, until the Emacs process is killed. If the problem happens when Emacs starts up, put this expression into your .emacs file so that the termscript file will be open when Emacs displays the screen for the first time.
Be warned: it is often difficult, and sometimes impossible, to fix a terminal-dependent bug without access to a terminal of the type that stimulates the bug.
echo LC_ALL=$LC_ALL LC_COLLATE=$LC_COLLATE LC_CTYPE=$LC_CTYPE \
LC_MESSAGES=$LC_MESSAGES LC_TIME=$LC_TIME LANG=$LANG
Alternatively, use the locale command, if your system has it, to display your locale settings.
You can use the M-! command to execute these commands from
Emacs, and then copy the output from the ‘*Messages*’ buffer into
the bug report. Alternatively, M-x getenv <RET> LC_ALL
<RET> will display the value of LC_ALL in the echo area, and
you can copy its output from the ‘*Messages*’ buffer.
Of course, if the bug is that Emacs gets a fatal signal, then one can't miss it. But if the bug is incorrect text, the maintainer might fail to notice what is wrong. Why leave it to chance?
Even if the problem you experience is a fatal signal, you should still say so explicitly. Suppose something strange is going on, such as, your copy of the source is out of sync, or you have encountered a bug in the C library on your system. (This has happened!) Your copy might crash and the copy here might not. If you said to expect a crash, then when Emacs here fails to crash, we would know that the bug was not happening. If you don't say to expect a crash, then we would not know whether the bug was happening—we would not be able to draw any conclusion from our observations.
To get the error message text accurately, copy it from the ‘*Messages*’ buffer into the bug report. Copy all of it, not just part.
To make a backtrace for the error, use M-x toggle-debug-on-error before the error happens (that is to say, you must give that command and then make the bug happen). This causes the error to run the Lisp debugger, which shows you a backtrace. Copy the text of the debugger's backtrace into the bug report. See The Lisp Debugger, for information on debugging Emacs Lisp programs with the Edebug package.
This use of the debugger is possible only if you know how to make the bug happen again. If you can't make it happen again, at least copy the whole error message.
-q switch to prevent loading the init file). If
the problem does not occur then, you must report the precise
contents of any programs that you must load into the Lisp world in order
to cause the problem to occur.
The line numbers in the development sources don't match those in your sources. It would take extra work for the maintainers to determine what code is in your version at a given line number, and we could not be certain.
However, you need to think when you collect the additional information if you want it to show what causes the bug.
For example, many people send just a backtrace, but that is not very useful by itself. A simple backtrace with arguments often conveys little about what is happening inside GNU Emacs, because most of the arguments listed in the backtrace are pointers to Lisp objects. The numeric values of these pointers have no significance whatever; all that matters is the contents of the objects they point to (and most of the contents are themselves pointers).
To provide useful information, you need to show the values of Lisp objects in Lisp notation. Do this for each variable which is a Lisp object, in several stack frames near the bottom of the stack. Look at the source to see which variables are Lisp objects, because the debugger thinks of them as integers.
To show a variable's value in Lisp syntax, first print its value, then
use the user-defined GDB command pr to print the Lisp object in
Lisp syntax. (If you must use another debugger, call the function
debug_print with the object as an argument.) The pr
command is defined by the file .gdbinit, and it works only if you
are debugging a running process (not with a core dump).
To make Lisp errors stop Emacs and return to GDB, put a breakpoint at
Fsignal.
For a short listing of Lisp functions running, type the GDB
command xbacktrace.
The file .gdbinit defines several other commands that are useful
for examining the data types and contents of Lisp objects. Their names
begin with ‘x’. These commands work at a lower level than
pr, and are less convenient, but they may work even when
pr does not, such as when debugging a core dump or when Emacs has
had a fatal signal.
More detailed advice and other useful techniques for debugging Emacs are available in the file etc/DEBUG in the Emacs distribution. That file also includes instructions for investigating problems whereby Emacs stops responding (many people assume that Emacs is “hung,” whereas in fact it might be in an infinite loop).
To find the file etc/DEBUG in your Emacs installation, use the
directory name stored in the variable data-directory.
Here are some things that are not necessary in a bug report:
Often people who encounter a bug spend a lot of time investigating which changes to the input file will make the bug go away and which changes will not affect it.
This is often time-consuming and not very useful, because the way we will find the bug is by running a single example under the debugger with breakpoints, not by pure deduction from a series of examples. You might as well save time by not searching for additional examples. It is better to send the bug report right away, go back to editing, and find another bug to report.
Of course, if you can find a simpler example to report instead of the original one, that is a convenience. Errors in the output will be easier to spot, running under the debugger will take less time, etc.
However, simplification is not vital; if you can't do this or don't have time to try, please report the bug with your original test case.
Debugging the core dump might be useful, but it can only be done on your machine, with your Emacs executable. Therefore, sending the core dump file to the Emacs maintainers won't be useful. Above all, don't include the core file in an email bug report! Such a large message can be extremely inconvenient.
System-call traces are very useful for certain special kinds of debugging, but in most cases they give little useful information. It is therefore strange that many people seem to think that the way to report information about a crash is to send a system-call trace. Perhaps this is a habit formed from experience debugging programs that don't have source code or debugging symbols.
In most programs, a backtrace is normally far, far more informative than
a system-call trace. Even in Emacs, a simple backtrace is generally
more informative, though to give full information you should supplement
the backtrace by displaying variable values and printing them as Lisp
objects with pr (see above).
A patch for the bug is useful if it is a good one. But don't omit the other information that a bug report needs, such as the test case, on the assumption that a patch is sufficient. We might see problems with your patch and decide to fix the problem another way, or we might not understand it at all. And if we can't understand what bug you are trying to fix, or why your patch should be an improvement, we mustn't install it.
Such guesses are usually wrong. Even experts can't guess right about such things without first using the debugger to find the facts.
If you would like to write bug fixes or improvements for GNU Emacs, that is very helpful. When you send your changes, please follow these guidelines to make it easy for the maintainers to use them. If you don't follow these guidelines, your information might still be useful, but using it will take extra work. Maintaining GNU Emacs is a lot of work in the best of circumstances, and we can't keep up unless you do your best to help.
(Referring to a bug report is not as good as including it, because then we will have to look it up, and we have probably already deleted it if we've already fixed the bug.)
If you make two changes for separate reasons, then we might not want to install them both. We might want to install just one. If you send them all jumbled together in a single set of diffs, we have to do extra work to disentangle them—to figure out which parts of the change serve which purpose. If we don't have time for this, we might have to ignore your changes entirely.
If you send each change as soon as you have written it, with its own explanation, then two changes never get tangled up, and we can consider each one properly without any extra work to disentangle them.
Since you should send each change separately, you might as well send it right away. That gives us the option of installing it immediately if it is important.
If you have GNU diff, use ‘diff -c -F'^[_a-zA-Z0-9$]+ *('’ when making diffs of C code. This shows the name of the function that each change occurs in.
The purpose of the change log is to show people where to find what was changed. So you need to be specific about what functions you changed; in large functions, it's often helpful to indicate where within the function the change was.
On the other hand, once you have shown people where to find the change, you need not explain its purpose in the change log. Thus, if you add a new function, all you need to say about it is that it is new. If you feel that the purpose needs explaining, it probably does—but put the explanation in comments in the code. It will be more useful there.
Please read the ChangeLog files in the src and lisp directories to see what sorts of information to put in, and to learn the style that we use. If you would like your name to appear in the header line, showing who made the change, send us the header line. See Change Log.
Sometimes people send fixes that might be an improvement in general—but it is hard to be sure of this. It's hard to install such changes because we have to study them very carefully. Of course, a good explanation of the reasoning by which you concluded the change was correct can help convince us.
The safest changes are changes to the configuration files for a particular machine. These are safe because they can't create new bugs on other machines.
Please help us keep up with the workload by designing the patch in a form that is clearly safe to install.
If you would like to help pretest Emacs releases to assure they work well, or if you would like to work on improving Emacs, please contact the maintainers at emacs-devel@gnu.org. A pretester should be prepared to investigate bugs as well as report them. If you'd like to work on improving Emacs, please ask for suggested projects or suggest your own ideas.
If you have already written an improvement, please tell us about it. If you have not yet started work, it is useful to contact emacs-devel@gnu.org before you start; it might be possible to suggest ways to make your extension fit in better with the rest of Emacs.
The development version of Emacs can be downloaded from the CVS repository where it is actively maintained by a group of developers. See the Emacs project page http://savannah.gnu.org/projects/emacs/ for details.
If you need help installing, using or changing GNU Emacs, there are two ways to find it:
gnu.emacs.help. (This mailing list and newsgroup
interconnect, so it does not matter which one you use.)
Copyright © 1989, 1991 Free Software Foundation, Inc.
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software—to make sure the software is free for all its users. This General Public License applies to most of the Free Software Foundation's software and to any other program whose authors commit to using it. (Some other Free Software Foundation software is covered by the GNU Library General Public License instead.) You can apply it to your programs, too.
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To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it.
For example, if you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.
We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software.
Also, for each author's protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reflect on the original authors' reputations.
Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all.
The precise terms and conditions for copying, distribution and modification follow.
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You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.
These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.
Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.
In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.
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This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.
Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and “any later version,” you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation.
If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.
one line to give the program's name and an idea of what it does.
Copyright (C) 19yy name of author
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Also add information on how to contact you by electronic and paper mail.
If the program is interactive, make it output a short notice like this when it starts in an interactive mode:
Gnomovision version 69, Copyright (C) 20yy name of author
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
type `show w'. This is free software, and you are welcome
to redistribute it under certain conditions; type `show c'
for details.
The hypothetical commands ‘show w’ and ‘show c’ should show the appropriate parts of the General Public License. Of course, the commands you use may be called something other than ‘show w’ and ‘show c’; they could even be mouse-clicks or menu items—whatever suits your program.
You should also get your employer (if you work as a programmer) or your school, if any, to sign a “copyright disclaimer” for the program, if necessary. Here is a sample; alter the names:
Yoyodyne, Inc., hereby disclaims all copyright
interest in the program `Gnomovision'
(which makes passes at compilers) written
by James Hacker.
signature of Ty Coon, 1 April 1989
Ty Coon, President of Vice
This General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Library General Public License instead of this License.
Copyright (C) 2000,2001,2002 Free Software Foundation, Inc.
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
The purpose of this License is to make a manual, textbook, or other functional and useful document “free” in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.
This License is a kind of “copyleft”, which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.
We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.
This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The “Document”, below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as “you”. You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.
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The “Title Page” means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, “Title Page” means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text.
A section “Entitled XYZ” means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as “Acknowledgements”, “Dedications”, “Endorsements”, or “History”.) To “Preserve the Title” of such a section when you modify the Document means that it remains a section “Entitled XYZ” according to this definition.
The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.
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If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.
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You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:
A. Use in the Title Page (and on the covers, if any) a title distinct
from that of the Document, and from those of previous versions
(which should, if there were any, be listed in the History section
of the Document). You may use the same title as a previous version
if the original publisher of that version gives permission.
B. List on the Title Page, as authors, one or more persons or entities
responsible for authorship of the modifications in the Modified
Version, together with at least five of the principal authors of the
Document (all of its principal authors, if it has fewer than five),
unless they release you from this requirement.
C. State on the Title page the name of the publisher of the
Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license notice
giving the public permission to use the Modified Version under the
terms of this License, in the form shown in the Addendum below.
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and required Cover Texts given in the Document's license notice.
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to it an item stating at least the title, year, new authors, and
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it was based on. These may be placed in the “History” section.
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least four years before the Document itself, or if the original
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Preserve the Title of the section, and preserve in the section all
the substance and tone of each of the contributor acknowledgements
and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document,
unaltered in their text and in their titles. Section numbers
or the equivalent are not considered part of the section titles.
M. Delete any section Entitled “Endorsements.” Such a section
may not be included in the Modified Version.
N. Do not retitle any existing section to be Entitled “Endorsements”
or to conflict in title with any Invariant Section.
O. Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or
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of these sections as invariant. To do this, add their titles to the
list of Invariant Sections in the Modified Version's license notice.
These titles must be distinct from any other section titles.
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The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.
You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.
The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.
In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled “Acknowledgements”, and any sections Entitled “Dedications.” You must delete all sections Entitled “Endorsements.”
You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.
You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.
A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the copyright resulting from the compilation is not used to limit the legal rights of the compilation's users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document's Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.
Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.
If a section in the Document is Entitled “Acknowledgements”, “Dedications”, or “History”, the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.
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Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.
To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page:
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Permission is granted to copy, distribute and/or modify this document
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or any later version published by the Free Software Foundation;
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If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.
GNU Emacs supports command line arguments to request various actions when invoking Emacs. These are for compatibility with other editors and for sophisticated activities. We don't recommend using them for ordinary editing.
Arguments starting with ‘-’ are options, and so is ‘+linenum’. All other arguments specify files to visit. Emacs visits the specified files while it starts up. The last file name on your command line becomes the current buffer; the other files are also visited in other buffers. If there are two files, they are both displayed; otherwise the last file is displayed along with a buffer list that shows what other buffers there are. As with most programs, the special argument ‘--’ says that all subsequent arguments are file names, not options, even if they start with ‘-’.
Emacs command options can specify many things, such as the size and position of the X window Emacs uses, its colors, and so on. A few options support advanced usage, such as running Lisp functions on files in batch mode. The sections of this chapter describe the available options, arranged according to their purpose.
There are two ways of writing options: the short forms that start with a single ‘-’, and the long forms that start with ‘--’. For example, ‘-d’ is a short form and ‘--display’ is the corresponding long form.
The long forms with ‘--’ are easier to remember, but longer to type. However, you don't have to spell out the whole option name; any unambiguous abbreviation is enough. When a long option takes an argument, you can use either a space or an equal sign to separate the option name and the argument. Thus, you can write either ‘--display sugar-bombs:0.0’ or ‘--display=sugar-bombs:0.0’. We recommend an equal sign because it makes the relationship clearer, and the tables below always show an equal sign.
Most options specify how to initialize Emacs, or set parameters for
the Emacs session. We call them initial options. A few options
specify things to do: for example, load libraries, call functions, or
terminate Emacs. These are called action options. These and file
names together are called action arguments. Emacs processes all
the action arguments in the order they are written. The .emacs file
can access the values of the action arguments as the elements of a list in
the variable command-line-args.
Here is a table of the action arguments and options:
find-file. See Visiting.
If you visit several files at startup in this way, Emacs
also displays a Buffer Menu buffer to show you what files it
has visited. You can inhibit that by setting inhibit-startup-buffer-menu to t.
find-file, then go to line number
linenum in it.
find-file, then go to line number
linenum and put point at column number columnnum.
load.
See Lisp Libraries. If file is not an absolute file name,
the library can be found either in the current directory, or in the
Emacs library search path as specified with EMACSLOADPATH
(see General Variables).
Warning: If previous command-line arguments have visited
files, the current directory is the directory of the last file
visited.
load-path.
The initial options specify parameters for the Emacs session. This section describes the more general initial options; some other options specifically related to the X Window System appear in the following sections.
Some initial options affect the loading of init files. The normal actions of Emacs are to first load site-start.el if it exists, then your own init file ~/.emacs if it exists, and finally default.el if it exists. See Init File. Certain options prevent loading of some of these files or substitute other files for them.
In batch mode, Emacs does not display the text being edited, and the
standard terminal interrupt characters such as C-z and C-c
continue to have their normal effect. The functions prin1,
princ and print output to stdout instead of the
echo area, while message and error messages output to
stderr. Functions that would normally read from the minibuffer
take their input from stdin instead.
‘--batch’ implies ‘-q’ (do not load an init file), but
site-start.el is loaded nonetheless. It also causes Emacs to
exit after processing all the command options. In addition, it
disables auto-saving except in buffers for which it has been
explicitly requested.
The normal use of this option is in executable script files that run Emacs. They can start with this text on the first line
#!/usr/bin/emacs --script
which will invoke Emacs with ‘--script’ and supply the name of
the script file as file. Emacs Lisp then treats ‘#!’ as a
comment delimiter.
inhibit-startup-message to non-nil.
Here is an example of using Emacs with arguments and options. It assumes you have a Lisp program file called hack-c.el which, when loaded, performs some useful operation on the current buffer, expected to be a C program.
emacs --batch foo.c -l hack-c -f save-buffer >& log
This says to visit foo.c, load hack-c.el (which makes
changes in the visited file), save foo.c (note that
save-buffer is the function that C-x C-s is bound to), and
then exit back to the shell (because of ‘--batch’). ‘--batch’
also guarantees there will be no problem redirecting output to
log, because Emacs will not assume that it has a display terminal
to work with.
You can specify action arguments for Emacs when you resume it after a suspension. To prepare for this, put the following code in your .emacs file (see Hooks):
(add-hook 'suspend-hook 'resume-suspend-hook)
(add-hook 'suspend-resume-hook 'resume-process-args)
As further preparation, you must execute the shell script
emacs.csh (if you use csh as your shell) or emacs.bash
(if you use bash as your shell). These scripts define an alias named
edit, which will resume Emacs giving it new command line
arguments such as files to visit. The scripts are found in the
etc subdirectory of the Emacs distribution.
Only action arguments work properly when you resume Emacs. Initial arguments are not recognized—it's too late to execute them anyway.
Note that resuming Emacs (with or without arguments) must be done from
within the shell that is the parent of the Emacs job. This is why
edit is an alias rather than a program or a shell script. It is
not possible to implement a resumption command that could be run from
other subjobs of the shell; there is no way to define a command that could
be made the value of EDITOR, for example. Therefore, this feature
does not take the place of the Emacs Server feature (see Emacs Server).
The aliases use the Emacs Server feature if you appear to have a server Emacs running. However, they cannot determine this with complete accuracy. They may think that a server is still running when in actuality you have killed that Emacs, because the file /tmp/esrv... still exists. If this happens, find that file and delete it.
The environment is a feature of the operating system; it consists of a collection of variables with names and values. Each variable is called an environment variable; environment variable names are case-sensitive, and it is conventional to use upper case letters only. The values are all text strings.
What makes the environment useful is that subprocesses inherit the environment automatically from their parent process. This means you can set up an environment variable in your login shell, and all the programs you run (including Emacs) will automatically see it. Subprocesses of Emacs (such as shells, compilers, and version-control software) inherit the environment from Emacs, too.
Inside Emacs, the command M-x getenv gets the value of an environment variable. M-x setenv sets a variable in the Emacs environment. (Environment variable substitutions with ‘$’ work in the value just as in file names; see File Names with $.)
The way to set environment variables outside of Emacs depends on the operating system, and especially the shell that you are using. For example, here's how to set the environment variable ORGANIZATION to ‘not very much’ using Bash:
export ORGANIZATION="not very much"
and here's how to do it in csh or tcsh:
setenv ORGANIZATION "not very much"
When Emacs is using the X Window System, various environment variables that control X work for Emacs as well. See the X documentation for more information.
Here is an alphabetical list of specific environment variables that have special meanings in Emacs, giving the name of each variable and its meaning. Most of these variables are also used by some other programs. Emacs does not require any of these environment variables to be set, but it uses their values if they are set.
cd command to search for the directory you specify,
when you specify a relative directory name.
data-directory.
doc-directory.
load-path.
exec-path.
complete package
to search for files.
On MS-Windows, if LANG is not already set in the environment when Emacs starts, Emacs sets it based on the system-wide default language, which you can set in the ‘Regional Settings’ Control Panel on some versions of MS-Windows.
The value of the LC_CTYPE category is
matched against entries in locale-language-names,
locale-charset-language-names, and
locale-preferred-coding-systems, to select a default language
environment and coding system. See Language Environments.
exec-path.
mail-default-reply-to. See Mail Headers.
version-control variable (see Backup Names).
These variables are used only on particular configurations:
The value of this variable should be the two-character encoding of the foreground (the first character) and the background (the second character) colors of the default face. Each character should be the hexadecimal code for the desired color on a standard PC text-mode display. For example, to get blue text on a light gray background, specify ‘EMACSCOLORS=17’, since 1 is the code of the blue color and 7 is the code of the light gray color.
The PC display usually supports only eight background colors. However,
Emacs switches the DOS display to a mode where all 16 colors can be used
for the background, so all four bits of the background color are
actually used.
On MS-Windows, the installation program addpm.exe adds values for emacs_dir, EMACSLOADPATH, EMACSDATA, EMACSPATH, EMACSDOC, SHELL and TERM to the HKEY_LOCAL_MACHINE section of the system registry, under /Software/GNU/Emacs. It does this because there is no standard place to set environment variables across different versions of Windows. Running addpm.exe is no longer strictly necessary in recent versions of Emacs, but if you are upgrading from an older version, running addpm.exe ensures that you do not have older registry entries from a previous installation, which may not be compatible with the latest version of Emacs.
When Emacs starts, as well as checking the environment, it also checks the System Registry for those variables and for HOME, LANG and PRELOAD_WINSOCK.
To determine the value of those variables, Emacs goes through the following procedure. First, the environment is checked. If the variable is not found there, Emacs looks for registry keys by that name under /Software/GNU/Emacs; first in the HKEY_CURRENT_USER section of the registry, and if not found there, in the HKEY_LOCAL_MACHINE section. Finally, if Emacs still cannot determine the values, compiled-in defaults are used.
In addition to the environment variables above, you can also add many of the settings which on X belong in the .Xdefaults file (see X Resources) to the /Software/GNU/Emacs registry key. Settings you add to the HKEY_LOCAL_MACHINE section will affect all users of the machine. Settings you add to the HKEY_CURRENT_USER section will only affect you, and will override machine wide settings.
The environment variable DISPLAY tells all X clients, including Emacs, where to display their windows. Its value is set by default in ordinary circumstances, when you start an X server and run jobs locally. Occasionally you may need to specify the display yourself; for example, if you do a remote login and want to run a client program remotely, displaying on your local screen.
With Emacs, the main reason people change the default display is to let them log into another system, run Emacs on that system, but have the window displayed at their local terminal. You might need to log in to another system because the files you want to edit are there, or because the Emacs executable file you want to run is there.
The syntax of the DISPLAY environment variable is ‘host:display.screen’, where host is the host name of the X Window System server machine, display is an arbitrarily-assigned number that distinguishes your server (X terminal) from other servers on the same machine, and screen is a rarely-used field that allows an X server to control multiple terminal screens. The period and the screen field are optional. If included, screen is usually zero.
For example, if your host is named ‘glasperle’ and your server is the first (or perhaps the only) server listed in the configuration, your DISPLAY is ‘glasperle:0.0’.
You can specify the display name explicitly when you run Emacs, either by changing the DISPLAY variable, or with the option ‘-d display’ or ‘--display=display’. Here is an example:
emacs --display=glasperle:0 &
You can inhibit the direct use of the window system and GUI with the ‘-nw’ option. It tells Emacs to display using ordinary ASCII on its controlling terminal. This is also an initial option.
Sometimes, security arrangements prevent a program on a remote system from displaying on your local system. In this case, trying to run Emacs produces messages like this:
Xlib: connection to "glasperle:0.0" refused by server
You might be able to overcome this problem by using the xhost command on the local system to give permission for access from your remote machine.
By default, Emacs displays text in a twelve point Courier font (when using X). You can specify a different font on your command line through the option ‘-fn name’ (or ‘--font’, which is an alias for ‘-fn’).
Under X, each font has a long name which consists of fourteen words or numbers, separated by dashes. Some fonts also have shorter nicknames. For instance, ‘9x15’ is such a nickname. This font makes each character nine pixels wide and fifteen pixels high. You can use either kind of name. Case is insignificant in both kinds. You can use wildcard patterns for the font name; then Emacs lets X choose one of the fonts that match the pattern. The wildcard character ‘*’ matches any sequence of characters (including none) and ‘?’ matches any single character. However, matching is implementation-dependent, and can be inaccurate when wildcards match dashes in a long name. For reliable results, supply all 14 dashes and use wildcards only within a field. Here is an example, which happens to specify the font whose nickname is ‘6x13’:
emacs -fn \
"-misc-fixed-medium-r-semicondensed--13-*-*-*-c-60-iso8859-1" &
You can also specify the font in your .Xdefaults file:
emacs.font: -misc-fixed-medium-r-semicondensed--13-*-*-*-c-60-iso8859-1
Note that if you use a wildcard pattern on the command line, you need to enclose it in single or double quotes, to prevent the shell from accidentally expanding it into a list of file names. On the other hand, you should not quote the name in the .Xdefaults file.
The default font used by Emacs (under X) is:
-adobe-courier-medium-r-*-*-*-120-*-*-*-*-iso8859-1
A long font name has the following form:
-maker-family-weight-slant-widthtype-style...
...-pixels-height-horiz-vert-spacing-width-registry-encoding
You will probably want to use a fixed-width default font—that is, a font in which all characters have the same width. Any font with ‘m’ or ‘c’ in the spacing field of the long name is a fixed-width font. Here's how to use the xlsfonts program to list all the fixed-width fonts available on your system:
xlsfonts -fn '*x*' | egrep "^[0-9]+x[0-9]+"
xlsfonts -fn '*-*-*-*-*-*-*-*-*-*-*-m*'
xlsfonts -fn '*-*-*-*-*-*-*-*-*-*-*-c*'
To see what a particular font looks like, use the xfd command. For example:
xfd -fn 6x13
displays the entire font ‘6x13’.
While running Emacs, you can set the font of the current frame (see Frame Parameters) or for a specific kind of text (see Faces).
On a color display, you can specify which color to use for various
parts of the Emacs display. To find out what colors are available on
your system, type M-x list-colors-display, or press
C-Mouse-2 and select ‘Display Colors’ from the pop-up menu.
(A particular window system might support many more colors, but the
list displayed by list-colors-display shows their portable
subset that can be safely used on any display supported by Emacs.)
If you do not specify colors, on windowed displays the default for the
background is white and the default for all other colors is black. On a
monochrome display, the foreground is black, the background is white,
and the border is gray if the display supports that. On terminals, the
background is usually black and the foreground is white.
Here is a list of the command-line options for specifying colors:
For example, to use a coral mouse cursor and a slate blue text cursor, enter:
emacs -ms coral -cr 'slate blue' &
You can reverse the foreground and background colors through the ‘-rv’ option or with the X resource ‘reverseVideo’.
The ‘-fg’, ‘-bg’, and ‘-rv’ options function on text-only terminals as well as on window systems.
Here is a list of the command-line options for specifying size and position of the initial Emacs frame:
In the ‘--geometry’ option, {+-} means either a plus
sign or a minus sign. A plus
sign before xoffset means it is the distance from the left side of
the screen; a minus sign means it counts from the right side. A plus
sign before yoffset means it is the distance from the top of the
screen, and a minus sign there indicates the distance from the bottom.
The values xoffset and yoffset may themselves be positive or
negative, but that doesn't change their meaning, only their direction.
Emacs uses the same units as xterm does to interpret the geometry. The width and height are measured in characters, so a large font creates a larger frame than a small font. (If you specify a proportional font, Emacs uses its maximum bounds width as the width unit.) The xoffset and yoffset are measured in pixels.
You do not have to specify all of the fields in the geometry specification. If you omit both xoffset and yoffset, the window manager decides where to put the Emacs frame, possibly by letting you place it with the mouse. For example, ‘164x55’ specifies a window 164 columns wide, enough for two ordinary width windows side by side, and 55 lines tall.
The default width for Emacs is 80 characters and the default height is 40 lines. You can omit either the width or the height or both. If you start the geometry with an integer, Emacs interprets it as the width. If you start with an ‘x’ followed by an integer, Emacs interprets it as the height. Thus, ‘81’ specifies just the width; ‘x45’ specifies just the height.
If you start with ‘+’ or ‘-’, that introduces an offset, which means both sizes are omitted. Thus, ‘-3’ specifies the xoffset only. (If you give just one offset, it is always xoffset.) ‘+3-3’ specifies both the xoffset and the yoffset, placing the frame near the bottom left of the screen.
You can specify a default for any or all of the fields in .Xdefaults file, and then override selected fields with a ‘--geometry’ option.
Since the mode line and the echo area occupy the last 2 lines of the frame, the height of the initial text window is 2 less than the height specified in your geometry. In non-X-toolkit versions of Emacs, the menu bar also takes one line of the specified number. But in the X toolkit version, the menu bar is additional and does not count against the specified height. The tool bar, if present, is also additional.
Enabling or disabling the menu bar or tool bar alters the amount of space available for ordinary text. Therefore, if Emacs starts up with a tool bar (which is the default), and handles the geometry specification assuming there is a tool bar, and then your ~/.emacs file disables the tool bar, you will end up with a frame geometry different from what you asked for. To get the intended size with no tool bar, use an X resource to specify “no tool bar” (see Table of Resources); then Emacs will already know there's no tool bar when it processes the specified geometry.
When using one of ‘--fullscreen’, ‘--fullwidth’ or ‘--fullheight’ there may be some space around the frame anyway. That is because Emacs rounds the sizes so they are an even number of character heights and widths.
Some window managers have options that can make them ignore both program-specified and user-specified positions (sawfish is one). If these are set, Emacs fails to position the window correctly.
An Emacs frame has an internal border and an external border. The internal border is an extra strip of the background color around the text portion of the frame. Emacs itself draws the internal border. The external border is added by the window manager outside the frame; depending on the window manager you use, it may contain various boxes you can click on to move or iconify the window.
When you specify the size of the frame, that does not count the borders. The frame's position is measured from the outside edge of the external border.
Use the ‘-ib n’ option to specify an internal border n pixels wide. The default is 1. Use ‘-bw n’ to specify the width of the external border (though the window manager may not pay attention to what you specify). The default width of the external border is 2.
An Emacs frame may or may not have a specified title. The frame title, if specified, appears in window decorations and icons as the name of the frame. If an Emacs frame has no specified title, the default title has the form ‘invocation-name@machine’ (if there is only one frame) or the selected window's buffer name (if there is more than one frame).
You can specify a title for the initial Emacs frame with a command line option:
The ‘--name’ option (see Resources) also specifies the title for the initial Emacs frame.
Most window managers allow the user to “iconify” a frame, removing it from sight, and leaving a small, distinctive “icon” window in its place. Clicking on the icon window makes the frame itself appear again. If you have many clients running at once, you can avoid cluttering up the screen by iconifying most of the clients.
By default Emacs uses an icon window containing a picture of the GNU gnu. The ‘-nbi’ or ‘--no-bitmap-icon’ option tells Emacs to let the window manager choose what sort of icon to use—usually just a small rectangle containing the frame's title.
The ‘-iconic’ option tells Emacs to begin running as an icon, rather than showing a frame right away. In this situation, the icon is the only indication that Emacs has started; the text frame doesn't appear until you deiconify it.
The ‘--xrm’ option (see Resources) specifies additional X resource values.
You can customize some X-related aspects of Emacs behavior using X resources, as is usual for programs that use X. On MS-Windows, you can customize some of the same aspects using the system registry. See MS-Windows Registry.
When Emacs is built using an `X toolkit', such as Lucid or LessTif, you need to use X resources to customize the appearance of the widgets, including the menu-bar, scroll-bar, and dialog boxes. This is because the libraries that implement these don't provide for customization through Emacs. GTK+ widgets use a separate system of `GTK resources', which we will also describe.
Programs running under the X Window System organize their user options under a hierarchy of classes and resources. You can specify default values for these options in your X resources file, usually named ~/.Xdefaults or ~/.Xresources. If changes in ~/.Xdefaults do not take effect, it is because your X server stores its own list of resources; to update them, use the shell command xrdb—for instance, ‘xrdb ~/.Xdefaults’.
Each line in the file specifies a value for one option or for a collection of related options, for one program or for several programs (optionally even for all programs).
MS-Windows systems don't support ~/.Xdefaults files, but Emacs compiled for Windows looks for X resources in the Windows Registry, under the key ‘HKEY_CURRENT_USER\SOFTWARE\GNU\Emacs’ and then under the key ‘HKEY_LOCAL_MACHINE\SOFTWARE\GNU\Emacs’. The menu and scrollbars are native widgets on MS-Windows, so they are only customizable via the system-wide settings in the Display Control Panel. You can also set resources using the ‘-xrm’ command line option (see below.)
Programs define named resources with particular meanings. They also define how to group resources into named classes. For instance, in Emacs, the ‘internalBorder’ resource controls the width of the internal border, and the ‘borderWidth’ resource controls the width of the external border. Both of these resources are part of the ‘BorderWidth’ class. Case distinctions are significant in these names.
Every resource definition is associated with a specific program name—the name of the executable file that you ran. For Emacs, that is normally ‘emacs’. To specify a definition for all instances of Emacs, regardless of their names, use ‘Emacs’.
In ~/.Xdefaults, you can specify a value for a single resource on one line, like this:
emacs.borderWidth: 2
Or you can use a class name to specify the same value for all resources in that class. Here's an example:
emacs.BorderWidth: 2
If you specify a value for a class, it becomes the default for all resources in that class. You can specify values for individual resources as well; these override the class value, for those particular resources. Thus, this example specifies 2 as the default width for all borders, but overrides this value with 4 for the external border:
emacs.BorderWidth: 2
emacs.borderWidth: 4
The order in which the lines appear in the file does not matter. Also, command-line options always override the X resources file. Here is a list of X command-line options and their corresponding resource names.
If you don't specify this option, the default is to use the Emacs
executable's name as the resource name.
For consistency, ‘-name’ also specifies the name to use for other resource values that do not belong to any particular frame.
The resources that name Emacs invocations also belong to a class; its name is ‘Emacs’. If you write ‘Emacs’ instead of ‘emacs’, the resource applies to all frames in all Emacs jobs, regardless of frame titles and regardless of the name of the executable file. Here is an example:
Emacs.BorderWidth: 2
Emacs.borderWidth: 4
You can specify a string of additional resource values for Emacs to use with the command line option ‘-xrm resources’. The text resources should have the same format that you would use inside a file of X resources. To include multiple resource specifications in resources, put a newline between them, just as you would in a file. You can also use ‘#include "filename"’ to include a file full of resource specifications. Resource values specified with ‘-xrm’ take precedence over all other resource specifications.
One way to experiment with the effect of different resource settings
is to use the editres program. Select ‘Get Tree’ from the
‘Commands’ menu, then click on an Emacs frame. This will display
a tree showing the structure of X toolkit widgets used in an Emacs
frame. Select one of them, such as ‘menubar’, then select
‘Show Resource Box’ from the ‘Commands’ menu. This displays
a list of all the meaningful X resources and allows you to edit them.
Changes take effect immediately if you click on the ‘Apply’ button.
(See the editres man page for more details.)
This table lists the resource names that designate options for Emacs, not counting those for the appearance of the menu bar, each with the class that it belongs to:
background (class Background)bitmapIcon (class BitmapIcon)borderColor (class BorderColor)borderWidth (class BorderWidth)cursorColor (class Foreground)cursorBlink (class CursorBlink)font (class Font)foreground (class Foreground)geometry (class Geometry)If this resource specifies a position, that position applies only to the
initial Emacs frame (or, in the case of a resource for a specific frame
name, only that frame). However, the size, if specified here, applies to
all frames.
fullscreen (class Fullscreen)fullboth,
fullwidth or fullheight, which correspond to
the command-line options ‘-fs’, ‘-fw’, and ‘-fh’
(see Window Size X).
Note that this applies to all frames created, not just the initial
one.
iconName (class Title)internalBorder (class BorderWidth)lineSpacing (class LineSpacing)menuBar (class MenuBar)minibuffer (class Minibuffer)paneFont (class Font)pointerColor (class Foreground)privateColormap (class PrivateColormap)reverseVideo (class ReverseVideo)screenGamma (class ScreenGamma)screen-gamma.
selectionFont (class SelectionFont)selectionTimeout (class SelectionTimeout)synchronous (class Synchronous)title (class Title)toolBar (class ToolBar)auto-resize-tool-bars is non-nil, the tool bar's size
will be changed automatically so that all tool bar items are visible.
useXIM (class UseXIM)verticalScrollBars (class ScrollBars)visualClass (class VisualClass)The value should start with one of ‘TrueColor’, ‘PseudoColor’, ‘DirectColor’, ‘StaticColor’, ‘GrayScale’, and ‘StaticGray’, followed by ‘-depth’, where depth is the number of color planes. Most terminals only allow a few “visuals,” and the ‘dpyinfo’ program outputs information saying which ones.
You can also use resources to customize the appearance of particular faces (see Faces):
.attributeFont.attributeForeground.attributeBackground.attributeUnderline.attributeFamily.attributeWidthultra-condensed, extra-condensed,
condensed, semi-condensed, normal,
semi-expanded, expanded, extra-expanded, or
ultra-expanded.
.attributeHeight.attributeWeightultra-bold, extra-bold, bold,
semi-bold, normal, semi-light, light,
extra-light, ultra-light.
.attributeSlantitalic, oblique, normal,
reverse-italic, or reverse-oblique.
.attributeStrikeThrough.attributeOverline.attributeBox.attributeInverse.attributeStipplefalse to not use stipple for the face face.
.attributeBackgroundPixmapfalse.
.attributeBold.attributeItalicIf the Emacs installed at your site was built to use the X toolkit with the Lucid menu widgets, then the menu bar is a separate widget and has its own resources. The resource names contain ‘pane.menubar’ (following, as always, the name of the Emacs invocation, or ‘Emacs’, which stands for all Emacs invocations). Specify them like this:
Emacs.pane.menubar.resource: value
For example, to specify the font ‘8x16’ for the menu-bar items, write this:
Emacs.pane.menubar.font: 8x16
Resources for non-menubar toolkit pop-up menus have ‘menu*’, in like fashion. For example, to specify the font ‘8x16’ for the pop-up menu items, write this:
Emacs.menu*.font: 8x16
For dialog boxes, use ‘dialog’ instead of ‘menu’:
Emacs.dialog*.font: 8x16
The Lucid menus can display multilingual text in your locale. For more information about fontsets see the man page for XCreateFontSet. To enable multilingual menu text you specify a fontSet resource instead of the font resource. If both font and fontSet resources are specified, the fontSet resource is used. To specify ‘-*-helvetica-medium-r-*--*-120-*-*-*-*-*-*,*’ for both the popup and menu bar menus, write this:
Emacs*fontSet: -*-helvetica-medium-r-*--*-120-*-*-*-*-*-*,*
Experience shows that on some systems you may need to add ‘shell.’ before the ‘pane.menubar’ or ‘menu*’. On some other systems, you must not add ‘shell.’.
Here is a list of the specific resources for menu bars and pop-up menus:
fontfontSetforegroundbackgroundbuttonForegroundhorizontalSpacingverticalSpacingarrowSpacingshadowThicknessAlso determines the thickness of shadow lines around other objects,
for instance 3D buttons and arrows. If you have the impression that
the arrows in the menus do not stand out clearly enough or that the
difference between “in” and “out” buttons is difficult to see, set
this to 2. If you have no problems with visibility, the default
probably looks better. The background color may also have some effect
on the contrast.
marginIf the Emacs installed at your site was built to use the X toolkit with the LessTif or Motif widgets, then the menu bar, the dialog boxes, the pop-up menus, and the file-selection box are separate widgets and have their own resources.
The resource names for the menu bar contain ‘pane.menubar’ (following, as always, the name of the Emacs invocation, or ‘Emacs’, which stands for all Emacs invocations). Specify them like this:
Emacs.pane.menubar.subwidget.resource: value
Each individual string in the menu bar is a subwidget; the subwidget's name is the same as the menu item string. For example, the word ‘File’ in the menu bar is part of a subwidget named ‘emacs.pane.menubar.File’. Most likely, you want to specify the same resources for the whole menu bar. To do this, use ‘*’ instead of a specific subwidget name. For example, to specify the font ‘8x16’ for the menu-bar items, write this:
Emacs.pane.menubar.*.fontList: 8x16
This also specifies the resource value for submenus.
Each item in a submenu in the menu bar also has its own name for X resources; for example, the ‘File’ submenu has an item named ‘Save (current buffer)’. A resource specification for a submenu item looks like this:
Emacs.pane.menubar.popup_*.menu.item.resource: value
For example, here's how to specify the font for the ‘Save (current buffer)’ item:
Emacs.pane.menubar.popup_*.File.Save (current buffer).fontList: 8x16
For an item in a second-level submenu, such as ‘Complete Word’ under ‘Spell Checking’ under ‘Tools’, the resource fits this template:
Emacs.pane.menubar.popup_*.popup_*.menu.resource: value
For example,
Emacs.pane.menubar.popup_*.popup_*.Spell Checking.Complete Word: value
(This should be one long line.)
It's impossible to specify a resource for all the menu-bar items without also specifying it for the submenus as well. So if you want the submenu items to look different from the menu bar itself, you must ask for that in two steps. First, specify the resource for all of them; then, override the value for submenus alone. Here is an example:
Emacs.pane.menubar.*.fontList: 8x16
Emacs.pane.menubar.popup_*.fontList: 8x16
For LessTif pop-up menus, use ‘menu*’ instead of ‘pane.menubar’. For example, to specify the font ‘8x16’ for the pop-up menu items, write this:
Emacs.menu*.fontList: 8x16
For LessTif dialog boxes, use ‘dialog’ instead of ‘menu’:
Emacs.dialog*.fontList: 8x16
Emacs.dialog*.foreground: hotpink
To specify resources for the LessTif file-selection box, use ‘fsb*’, like this:
Emacs.fsb*.fontList: 8x16
Here is a list of the specific resources for LessTif menu bars and pop-up menus:
armColorfontListmarginBottommarginHeightmarginLeftmarginRightmarginTopmarginWidthborderWidthshadowThicknessbottomShadowColortopShadowColorIf Emacs was built to use the GTK widget set, then the menu bar, scroll bar and the dialogs are customized with the standard GTK customization file, ~/.gtkrc-2.0, or with the Emacs specific file ~/.emacs.d/gtkrc. We recommend that you use ~/.emacs.d/gtkrc for customizations, since ~/.gtkrc-2.0 seems to be ignored when running GConf with GNOME. These files apply only to GTK widget features. To customize Emacs font, background, faces, etc., use the normal X resources (see Resources).
Some GTK themes override these mechanisms, which means that using these mechanisms will not work to customize them.
In these files you first define a style and say what it means; then you specify to apply the style to various widget types (see GTK widget names). Here is an example of how to change the font for Emacs menus:
# Define the style ‘metafont’. style "menufont" { font_name = "helvetica bold 14" # This is a Pango font name } # Specify that widget type ‘*emacs-menuitem*’ uses ‘metafont’. widget "*emacs-menuitem*" style "menufont"
Here is a more elaborate example, showing how to change the parts of the scroll bar:
style "scroll"
{
fg[NORMAL] = "red" # The arrow color.
bg[NORMAL] = "yellow" # The thumb and background around the arrow.
bg[ACTIVE] = "blue" # The trough color.
bg[PRELIGHT] = "white" # The thumb color when the mouse is over it.
}
widget "*verticalScrollBar*" style "scroll"
There are also parameters that affect GTK as a whole. For example,
the property gtk-font-name sets the default font for GTK. You
must use Pango font names (see GTK styles). A GTK resources file
that just sets a default font looks like this:
gtk-font-name = "courier 12"
The GTK resources file is fully described in the GTK API document. This can be found in prefix/share/gtk-doc/html/gtk/gtk-resource-files.html, where prefix is the directory in which the GTK libraries were installed (usually /usr or /usr/local). You can also find the document online, at http://developer.gnome.org/doc/API/2.0/gtk/gtk-Resource-Files.html.
A GTK widget is specified by its widget class and
widget name. The widget class is the type of the widget: for
example, GtkMenuBar. The widget name is the name given to a
specific widget. A widget always has a class, but need not have a
name.
Absolute names are sequences of widget names or widget
classes, corresponding to hierarchies of widgets embedded within
other widgets. For example, if a GtkWindow named top
contains a GtkVBox named box, which in turn contains
a GtkMenuBar called menubar, the absolute class name
of the menu-bar widget is GtkWindow.GtkVBox.GtkMenuBar, and
its absolute widget name is top.box.menubar.
When assigning a style to a widget, you can use the absolute class name or the absolute widget name.
There are two commands to specify changes for widgets:
widget_classwidgetYou must specify the class and the style in double-quotes, and put these commands at the top level in the GTK customization file, like this:
style "menufont"
{
font_name = "helvetica bold 14"
}
widget "top.box.menubar" style "menufont"
widget_class "GtkWindow.GtkVBox.GtkMenuBar" style "menufont"
Matching of absolute names uses shell wildcard syntax: ‘*’
matches zero or more characters and ‘?’ matches one character.
This example assigns base_style to all widgets:
widget "*" style "base_style"
Given the absolute class name GtkWindow.GtkVBox.GtkMenuBar
and the corresponding absolute widget name top.box.menubar, all
these examples specify my_style for the menu bar:
widget_class "GtkWindow.GtkVBox.GtkMenuBar" style "my_style"
widget_class "GtkWindow.*.GtkMenuBar" style "my_style"
widget_class "*GtkMenuBar" style "my_style"
widget "top.box.menubar" style "my_style"
widget "*box*menubar" style "my_style"
widget "*menubar" style "my_style"
widget "*menu*" style "my_style"
In Emacs, the top level widget for a frame is a GtkWindow
that contains a GtkVBox. The GtkVBox contains the
GtkMenuBar and a GtkFixed widget. The vertical scroll
bars, GtkVScrollbar, are contained in the GtkFixed
widget. The text you write in Emacs is drawn in the GtkFixed
widget.
Dialogs in Emacs are GtkDialog widgets. The file dialog is a
GtkFileSelection widget.
To set a style for the menu bar using the absolute class name, use:
widget_class "GtkWindow.GtkVBox.GtkMenuBar" style "my_style"
For the scroll bar, the absolute class name is:
widget_class
"GtkWindow.GtkVBox.GtkFixed.GtkVScrollbar"
style "my_style"
The names for the emacs widgets, and their classes, are:
emacs-filedialog
| GtkFileSelection
|
emacs-dialog
| GtkDialog
|
Emacs
| GtkWindow
|
pane
| GtkVHbox
|
emacs
| GtkFixed
|
verticalScrollBar
| GtkVScrollbar
|
emacs-toolbar
| GtkToolbar
|
menubar
| GtkMenuBar
|
emacs-menuitem
| anything in menus
|
Thus, for Emacs you can write the two examples above as:
widget "Emacs.pane.menubar" style "my_style"
widget "Emacs.pane.emacs.verticalScrollBar" style "my_style"
GTK absolute names are quite strange when it comes to menus and dialogs. The names do not start with ‘Emacs’, as they are free-standing windows and not contained (in the GTK sense) by the Emacs GtkWindow. To customize the dialogs and menus, use wildcards like this:
widget "*emacs-dialog*" style "my_dialog_style"
widget "*emacs-filedialog* style "my_file_style"
widget "*emacs-menuitem* style "my_menu_style"
If you specify a customization in ~/.emacs.d/gtkrc, then it automatically applies only to Emacs, since other programs don't read that file. For example, the drop down menu in the file dialog can not be customized by any absolute widget name, only by an absolute class name. This is because the widgets in the drop down menu do not have names and the menu is not contained in the Emacs GtkWindow. To have all menus in Emacs look the same, use this in ~/.emacs.d/gtkrc:
widget_class "*Menu*" style "my_menu_style"
In a GTK style you specify the appearance widgets shall have. You can specify foreground and background color, background pixmap and font. The edit widget (where you edit the text) in Emacs is a GTK widget, but trying to specify a style for the edit widget will have no effect. This is so that Emacs compiled for GTK is compatible with Emacs compiled for other X toolkits. The settings for foreground, background and font for the edit widget is taken from the X resources; see Resources. Here is an example of two style declarations, ‘default’ and ‘ruler’:
pixmap_path "/usr/share/pixmaps:/usr/include/X11/pixmaps"
style "default"
{
font_name = "helvetica 12"
bg[NORMAL] = { 0.83, 0.80, 0.73 }
bg[SELECTED] = { 0.0, 0.55, 0.55 }
bg[INSENSITIVE] = { 0.77, 0.77, 0.66 }
bg[ACTIVE] = { 0.0, 0.55, 0.55 }
bg[PRELIGHT] = { 0.0, 0.55, 0.55 }
fg[NORMAL] = "black"
fg[SELECTED] = { 0.9, 0.9, 0.9 }
fg[ACTIVE] = "black"
fg[PRELIGHT] = { 0.9, 0.9, 0.9 }
base[INSENSITIVE] = "#777766"
text[INSENSITIVE] = { 0.60, 0.65, 0.57 }
bg_pixmap[NORMAL] = "background.xpm"
bg_pixmap[INSENSITIVE] = "background.xpm"
bg_pixmap[ACTIVE] = "background.xpm"
bg_pixmap[PRELIGHT] = "<none>"
}
style "ruler" = "default"
{
font_name = "helvetica 8"
}
The style ‘ruler’ inherits from ‘default’. This way you can build on existing styles. The syntax for fonts and colors is described below.
As this example shows, it is possible to specify several values for foreground and background depending on the widget's state. The possible states are:
NORMALACTIVEbg[ACTIVE] = "red"
sets the scroll bar trough to red. Buttons that have been pressed but
not released yet (“armed”) are in this state.
PRELIGHTSELECTEDINSENSITIVEfg[INSENSITIVE] = "yellow".
Here are the things that can go in a style declaration:
bg[state] = colorbg; it uses base instead.
base[state] = colorbg_pixmap[state] = "pixmap"You can't specify the file by its absolute file name. GTK looks for
the pixmap file in directories specified in pixmap_path.
pixmap_path is a colon-separated list of directories within
double quotes, specified at the top level in a gtkrc file
(i.e. not inside a style definition; see example above):
pixmap_path "/usr/share/pixmaps:/usr/include/X11/pixmaps"
fg[state] = colortext.
text[state] = colorfont_name = "font"There are three ways to specify a color: by name, in hexadecimal form, and with an RGB triplet.
A color name is written within double quotes, for example "red".
Hexadecimal form is the same as in X:
#rrrrggggbbbb, where all three color specs
must have the same number of hex digits (1, 2, 3 or 4).
An RGB triplet looks like { r, g, b },
where r, g and b are either integers in the range
0-65535 or floats in the range 0.0-1.0.
Pango font names have the form “family-list style-options size”. family-list is a comma separated list of font families optionally terminated by a comma. This way you can specify several families and the first one found will be used. family corresponds to the second part in an X font name, for example in
-adobe-times-medium-r-normal--12-120-75-75-p-64-iso10646-1
the family name is “times”.
style-options is a whitespace separated list of words where each word
is a style, variant, weight, or stretch. The default value for all of
these is normal.
A `style' corresponds to the fourth part of an X font name. In X font
names it is the character ‘r’, ‘i’ or ‘o’; in Pango
font names the corresponding values are normal, italic,
or oblique.
A `variant' is either normal or small-caps.
Small caps is a font with the lower case characters replaced by
smaller variants of the capital characters.
Weight describes the “boldness” of a font. It corresponds to the third
part of an X font name. It is one of ultra-light, light,
normal, bold, ultra-bold, or heavy.
Stretch gives the width of the font relative to other designs within a
family. It corresponds to the fifth part of an X font name. It is one of
ultra-condensed, extra-condensed, condensed,
semi-condensed, normal, semi-expanded,
expanded, extra-expanded, or ultra-expanded.
size is a decimal number that describes the font size in points.
For those users who live backwards in time, here is information about downgrading to Emacs version 21.4. We hope you will enjoy the greater simplicity that results from the absence of many Emacs 22.0.50 features.
mode-line-inverse-video to control whether
mode lines are highlighted at all—nil means don't highlight
them.
setenv command does not expand ‘$’ at all.
apropos-sort-by-scores has been removed.
backward-kill-sexp is now bound to C-M-delete
and C-M-backspace. Be careful when using these key sequences!
It may shut down your X server, or reboot your operating system.
sentence-end has been eliminated in favor of a
more straightforward approach: directly setting the variable
sentence-end. For example, to end each sentence with a single
space, use
(setq sentence-end "[.?!][]\"')}]*\\($\\|[ \t]\\)[ \t\n]*")
fill-nobreak-predicate is no longer customizable,
and it can only hold a single function.
nobreak-char-display has been removed.
yank-excluded-properties has been removed.
Info-fontify.
You can still use C-x v v to do these operations if you wish; its meaning is unchanged. If you want to control the buffer's read-only flag without performing any version control operation, use M-x toggle-read-only.
etags features for customizing parsing using regexps
have been removed.
server-mode
command and server-name user option have been eliminated.
quail-show-key, for showing how to input a
character, has been removed.
keyboard-coding-system is always
nil, regardless of your locale settings. If you want some
other value, set it yourself.
code-pages library, which contained various 8-bit coding
systems, has been removed.
This section briefly describes the peculiarities of using Emacs under Mac OS with native window system support. For Mac OS X, Emacs can be built either without window system support, with X11, or with Carbon API. This section only applies to the Carbon build. For Mac OS Classic, Emacs can be built with or without Carbon API, and this section applies to either of them because they run on the native window system.
Emacs built on Mac OS X supports most of its major features except
display support of PostScript images. The following features of Emacs
are not supported on Mac OS Classic: unexec (dump-emacs),
asynchronous subprocesses (start-process), and networking
(open-network-stream). As a result, packages such as Gnus,
GUD, and Comint do not work. Synchronous subprocesses
(call-process) are supported on non-Carbon build, but
specially-crafted external programs are needed. Since external
programs to handle commands such as print-buffer and
diff are not available on Mac OS Classic, they are not
supported. Non-Carbon build on Mac OS Classic does not support some
features such as file dialogs, drag-and-drop, and Unicode menus.
On Mac, Emacs can use <control>, <command>, and <option>
keys as any of Emacs modifier keys except <SHIFT> (i.e.,
<ALT>, <CTRL>, <HYPER>, <META>, and <SUPER>). The
assignment is controlled by the variables mac-control-modifier,
mac-command-modifier, and mac-option-modifier. The
value for each of these variables can be one of the following symbols:
alt, control, hyper, meta, super,
and nil (no particular assignment). By default, the
<control> key works as <CTRL>, and the <command> key as
<META>.
For the <option> key, if mac-option-modifier is set to
nil, which is the default, the key works as the normal
<option> key, i.e., dead-key processing will work. This is useful
for entering non-ASCII Latin characters directly from the
Mac keyboard, for example.
Emacs recognizes the setting in the Keyboard control panel (Mac OS Classic) or the International system preference pane (Mac OS X) and supports international and alternative keyboard layouts (e.g., Dvorak) if its script is either Roman, Japanese, Traditional Chinese, Korean, Cyrillic, Simplified Chinese, or Central European. Keyboard layouts based on Unicode may not work properly. Selecting one of the layouts from the keyboard layout pull-down menu will affect how the keys typed on the keyboard are interpreted.
Mac OS intercepts and handles certain key combinations (e.g.,
<command>-<SPC> for switching input languages). These will not
be passed to Emacs. One can disable this interception by setting
mac-pass-command-to-system or mac-pass-control-to-system
to nil.
Especially for one-button mice, the multiple button feature can be
emulated by setting mac-emulate-three-button-mouse to t
or reverse. If set to t (reverse, respectively),
pressing the mouse button with the <option> key is recognized as
the second (third) button, and that with the <command> key is
recognized as the third (second) button.
For multi-button mice, the wheel button and the secondary button are
recognized as the second and the third button, respectively. If
mac-wheel-button-is-mouse-2 is set to nil, their roles
are exchanged.
Mac uses non-standard encodings for the upper 128 single-byte
characters. They also deviate from the ISO 2022 standard by using
character codes in the range 128-159. The coding systems
mac-roman, mac-centraleurroman, and mac-cyrillic
are used to represent these Mac encodings.
The fontset fontset-mac is created automatically when Emacs
is run on Mac, and used by default. It displays as many kinds of
characters as possible using 12-point Monaco as a base font. If you
see some character as a hollow box with this fontset, then it's almost
impossible to display it only by customizing font settings (see Mac Font Specs).
You can use input methods provided either by LEIM (see Input Methods) or Mac OS to enter international characters. To use the former, see the International Character Set Support section of the manual (see International).
Emacs on Mac OS automatically changes the value of
keyboard-coding-system according to the current keyboard
layout. So users don't need to set it manually, and even if set, it
will be changed when the keyboard layout change is detected next time.
The Mac clipboard and the Emacs kill ring (see Killing) are
synchronized by default: you can yank a piece of text and paste it
into another Mac application, or cut or copy one in another Mac
application and yank it into a Emacs buffer. This feature can be
disabled by setting x-select-enable-clipboard to nil.
One can still do copy and paste with another application from the Edit
menu.
On Mac, the role of the coding system for selection that is set by
set-selection-coding-system (see Specify Coding) is
two-fold. First, it is used as a preferred coding system for the
traditional text flavor that does not specify any particular encodings
and is mainly used by applications on Mac OS Classic. Second, it
specifies the intermediate encoding for the UTF-16 text flavor that is
mainly used by applications on Mac OS X.
When pasting UTF-16 text data from the clipboard, it is first
converted to the encoding specified by the selection coding system
using the converter in the Mac OS system, and then decoded into the
Emacs internal encoding using the converter in Emacs. If the first
conversion failed, then the UTF-16 data is converted similarly but via
UTF-8. Copying UTF-16 text to the clipboard goes through the inverse
path. The reason for this two-pass decoding is to avoid subtle
differences in Unicode mappings between the Mac OS system and Emacs
such as various kinds of hyphens, to deal with UTF-16 data in native
byte order with no byte order mark, and to minimize users'
customization. For example, users that mainly use Latin characters
would prefer Greek characters to be decoded into the
mule-unicode-0100-24ff charset, but Japanese users would prefer
them to be decoded into the japanese-jisx0208 charset. Since
the coding system for selection is automatically set according to the
system locale setting, users usually don't have to set it manually.
The default language environment (see Language Environments) is set according to the locale setting at the startup time. On Mac OS, the locale setting is consulted in the following order:
AppleLocale that is set by default on Mac OS X 10.3
and later.
AppleLanguages that is set by default on Mac OS X
10.1 and later.
mac-system-locale that is derived from the system
language and region codes. This variable is available on all
supported Mac OS versions including Mac OS Classic.
The default values of almost all variables about coding systems are also set according to the language environment. So usually you don't have to customize these variables manually.
On Mac OS X, when Emacs is run in a terminal, it inherits the values of environment variables from the shell from which it is invoked. However, when it is run from the Finder as a GUI application, it only inherits environment variable values defined in the file ~/.MacOSX/environment.plist that affects all the applications invoked from the Finder or the open command.
Command line arguments are specified like
/Applications/Emacs.app/Contents/MacOS/Emacs -geometry 80x25 &
if Emacs is installed at /Applications/Emacs.app. If Emacs is invoked like this, then it also inherits the values of environment variables from the shell from which it is invoked.
On Mac OS Classic, environment variables and command line arguments for Emacs can be set by modifying the ‘STR#’ resources 128 and 129, respectively. A common environment variable that one may want to set is ‘HOME’.
The way to set an environment variable is by adding a string of the form
ENV_VAR=VALUE
to resource ‘STR#’ number 128 using ResEdit. To set up the
program to use unibyte characters exclusively, for example, add the
string
EMACS_UNIBYTE=1
Although Emacs on Mac does not support X resources (see X Resources) directly, one can use the Preferences system in place of X resources. For example, adding the line
Emacs.cursorType: bar
to ~/.Xresources in X11 corresponds to the execution of
defaults write org.gnu.Emacs Emacs.cursorType bar
on Mac OS X. One can use boolean or numeric values as well as string values as follows:
defaults write org.gnu.Emacs Emacs.toolBar -bool false
defaults write org.gnu.Emacs Emacs.lineSpacing -int 3
Try M-x man RET defaults RET for the usage of the defaults command. Alternatively, if you have Developer Tools installed on Mac OS X, you can use Property List Editor to edit the file ~/Library/Preferences/org.gnu.Emacs.plist.
This node applies to Mac OS Classic only.
The directory structure in Mac OS Classic is seen by Emacs as
/volumename/filename
So when Emacs requests a file name, doing file name completion on / will display all volumes on the system. You can use .. to go up a directory level.
On Mac OS Classic, to access files and folders on the desktop, look
in the folder Desktop Folder in your boot volume (this folder
is usually invisible in the Mac Finder).
On Mac OS Classic, Emacs creates the Mac folder
:Preferences:Emacs: in the System Folder and uses it as
the temporary directory. Emacs maps the directory name /tmp/
to that. Therefore it is best to avoid naming a volume tmp.
If everything works correctly, the program should leave no files in it
when it exits. You should be able to set the environment variable
TMPDIR to use another directory but this folder will still be
created.
It is rare that you need to specify a font name in Emacs; usually you specify face attributes instead. For example, you can use 14pt Courier by customizing the default face attributes for all frames:
(set-face-attribute 'default nil :family "courier" :height 140)
Alternatively, an interactive one is also available (see Face Customization).
But when you do need to specify a font name in Emacs on Mac, use a standard X font name:
-maker-family-weight-slant-widthtype-style...
...-pixels-height-horiz-vert-spacing-width-charset
See Font X. Wildcards are supported as they are on X.
Native Apple fonts in Mac Roman encoding has maker name apple
and charset mac-roman. For example 12-point Monaco can be
specified by the name ‘-apple-monaco-*-12-*-mac-roman’. When
using a particular size of scalable fonts, it must be specified in a
format containing 14 ‘-’s like
‘-apple-monaco-medium-r-normal--13-*-*-*-*-*-mac-roman’.
You can specify a mac-roman font for ASCII
characters like
(add-to-list
'default-frame-alist
'(font . "-apple-monaco-medium-r-normal--13-*-*-*-*-*-mac-roman"))
but that does not extend to ISO-8859-1: specifying a mac-roman
font for Latin-1 characters introduces wrong glyphs.
Native Apple Traditional Chinese, Simplified Chinese, Japanese, Korean, Central European, Cyrillic, Symbol, and Dingbats fonts have charsets ‘big5-0’, ‘gb2312.1980-0’, ‘jisx0208.1983-sjis’ and ‘jisx0201.1976-0’, ‘ksc5601.1989-0’, ‘mac-centraleurroman’, ‘mac-cyrillic’, ‘mac-symbol’, and ‘mac-dingbats’, respectively.
Since Emacs as of the current version uses QuickDraw Text routines for drawing texts, only characters in the charsets listed above can be displayed with the OS-bundled fonts, even if other applications that use ATSUI or Cocoa can display variety of characters with them.
The use of create-fontset-from-fontset-spec (see Defining Fontsets) for defining fontsets often results in wrong ones
especially when using only OS-bundled fonts. The recommended way is
to create a fontset using create-fontset-from-mac-roman-font:
(create-fontset-from-mac-roman-font
"-apple-courier-medium-r-normal--13-*-*-*-*-*-mac-roman"
nil "foo")
and then optionally specifying Chinese, Japanese, or Korean font
families using set-fontset-font:
(set-fontset-font "fontset-foo"
'chinese-gb2312 '("song" . "gb2312.1980-0"))
Single-byte fonts converted from GNU fonts in BDF format, which are not in the Mac Roman encoding, have foundry, family, and character sets encoded in the names of their font suitcases. E.g., the font suitcase ‘ETL-Fixed-ISO8859-1’ contains fonts which can be referred to by the name ‘-ETL-fixed-*-iso8859-1’.
Emacs uses the QuickDraw text rendering by default. On Mac OS X
10.2 and later, it can be changed so that it uses the Quartz 2D text
rendering (aka CG text rendering) by setting
mac-allow-anti-aliasing to t. However, it is reported
to sometimes leave some garbages.
The function do-applescript takes a string argument,
executes it as an AppleScript command, and returns the result as a
string.
The function mac-file-name-to-posix takes a Mac file name and
returns the GNU or Unix equivalent. The function
posix-file-name-to-mac performs the opposite conversion. They
are useful for constructing AppleScript commands to be passed to
do-applescript.
The functions mac-set-file-creator,
mac-get-file-creator, mac-set-file-type, and
mac-get-file-type can be used to set and get creator and file
codes.
The function mac-get-preference returns the preferences value
converted to a Lisp object for a specified key and application.
This section briefly describes the peculiarities of using Emacs under the MS-DOS “operating system” (also known as “MS-DOG”). If you build Emacs for MS-DOS, the binary will also run on Windows 3.X, Windows NT, Windows 9X/ME, Windows 2000, or OS/2 as a DOS application; the information in this chapter applies for all of those systems, if you use an Emacs that was built for MS-DOS.
Note that it is possible to build Emacs specifically for Windows NT/2K or Windows 9X/ME. If you do that, most of this chapter does not apply; instead, you get behavior much closer to what is documented in the rest of the manual, including support for long file names, multiple frames, scroll bars, mouse menus, and subprocesses. However, the section on text files and binary files does still apply. There are also two sections at the end of this chapter which apply specifically for the Windows version.
The key that is called <DEL> in Emacs (because that's how it is designated on most workstations) is known as <BS> (backspace) on a PC. That is why the PC-specific terminal initialization remaps the <BS> key to act as <DEL>; the <DELETE> key is remapped to act as C-d for the same reasons.
Emacs built for MS-DOS recognizes C-<BREAK> as a quit character, just like C-g. This is because Emacs cannot detect that you have typed C-g until it is ready for more input. As a consequence, you cannot use C-g to stop a running command (see Quitting). By contrast, C-<BREAK> is detected as soon as you type it (as C-g is on other systems), so it can be used to stop a running command and for emergency escape (see Emergency Escape).
The PC keyboard maps use the left <ALT> key as the <META> key.
You have two choices for emulating the <SUPER> and <HYPER> keys:
choose either the right <CTRL> key or the right <ALT> key by
setting the variables dos-hyper-key and dos-super-key to 1
or 2 respectively. If neither dos-super-key nor
dos-hyper-key is 1, then by default the right <ALT> key is
also mapped to the <META> key. However, if the MS-DOS international
keyboard support program KEYB.COM is installed, Emacs will
not map the right <ALT> to <META>, since it is used for
accessing characters like ~ and @ on non-US keyboard
layouts; in this case, you may only use the left <ALT> as <META>
key.
The variable dos-keypad-mode is a flag variable that controls
what key codes are returned by keys in the numeric keypad. You can also
define the keypad <ENTER> key to act like C-j, by putting the
following line into your _emacs file:
;; Make the <ENTER> key from the numeric keypad act as C-j. (define-key function-key-map [kp-enter] [?\C-j])
Emacs on MS-DOS supports a mouse (on the default terminal only). The mouse commands work as documented, including those that use menus and the menu bar (see Menu Bar). Scroll bars don't work in MS-DOS Emacs. PC mice usually have only two buttons; these act as Mouse-1 and Mouse-2, but if you press both of them together, that has the effect of Mouse-3. If the mouse does have 3 buttons, Emacs detects that at startup, and all the 3 buttons function normally, as on X.
Help strings for menu-bar and pop-up menus are displayed in the echo area when the mouse pointer moves across the menu items. Highlighting of mouse-sensitive text (see Mouse References) is also supported.
Some versions of mouse drivers don't report the number of mouse buttons correctly. For example, mice with a wheel report that they have 3 buttons, but only 2 of them are passed to Emacs; the clicks on the wheel, which serves as the middle button, are not passed. In these cases, you can use the M-x msdos-set-mouse-buttons command to tell Emacs how many mouse buttons to expect. You could make such a setting permanent by adding this fragment to your _emacs init file:
;; Treat the mouse like a 2-button mouse.
(msdos-set-mouse-buttons 2)
Emacs built for MS-DOS supports clipboard operations when it runs on Windows. Commands that put text on the kill ring, or yank text from the ring, check the Windows clipboard first, just as Emacs does on the X Window System (see Mouse Commands). Only the primary selection and the cut buffer are supported by MS-DOS Emacs on Windows; the secondary selection always appears as empty.
Due to the way clipboard access is implemented by Windows, the length of text you can put into the clipboard is limited by the amount of free DOS memory that is available to Emacs. Usually, up to 620KB of text can be put into the clipboard, but this limit depends on the system configuration and is lower if you run Emacs as a subprocess of another program. If the killed text does not fit, Emacs outputs a message saying so, and does not put the text into the clipboard.
Null characters also cannot be put into the Windows clipboard. If the killed text includes null characters, Emacs does not put such text into the clipboard, and displays in the echo area a message to that effect.
The variable dos-display-scancodes, when non-nil,
directs Emacs to display the ASCII value and the keyboard scan code of
each keystroke; this feature serves as a complement to the
view-lossage command, for debugging.
Display on MS-DOS cannot use font variants, like bold or italic,
but it does support
multiple faces, each of which can specify a foreground and a background
color. Therefore, you can get the full functionality of Emacs packages
that use fonts (such as font-lock, Enriched Text mode, and
others) by defining the relevant faces to use different colors. Use the
list-colors-display command (see Frame Parameters) and the
list-faces-display command (see Faces) to see what colors and
faces are available and what they look like.
See MS-DOS and MULE, later in this chapter, for information on how Emacs displays glyphs and characters that aren't supported by the native font built into the DOS display.
When Emacs starts, it changes the cursor shape to a solid box. This
is for compatibility with other systems, where the box cursor is the
default in Emacs. This default shape can be changed to a bar by
specifying the cursor-type parameter in the variable
default-frame-alist (see Creating Frames). The MS-DOS
terminal doesn't support a vertical-bar cursor, so the bar cursor is
horizontal, and the width parameter, if specified by the
frame parameters, actually determines its height. For this reason,
the bar and hbar cursor types produce the same effect on
MS-DOS. As an extension, the bar cursor specification can include the
starting scan line of the cursor as well as its width, like this:
'(cursor-type bar width . start)
In addition, if the width parameter is negative, the cursor bar begins at the top of the character cell.
The MS-DOS terminal can only display a single frame at a time. The Emacs frame facilities work on MS-DOS much as they do on text-only terminals (see Frames). When you run Emacs from a DOS window on MS-Windows, you can make the visible frame smaller than the full screen, but Emacs still cannot display more than a single frame at a time.
The mode4350 command switches the display to 43 or 50
lines, depending on your hardware; the mode25 command switches
to the default 80x25 screen size.
By default, Emacs only knows how to set screen sizes of 80 columns by
25, 28, 35, 40, 43 or 50 rows. However, if your video adapter has
special video modes that will switch the display to other sizes, you can
have Emacs support those too. When you ask Emacs to switch the frame to
n rows by m columns dimensions, it checks if there is a
variable called screen-dimensions-nxm, and if so,
uses its value (which must be an integer) as the video mode to switch
to. (Emacs switches to that video mode by calling the BIOS Set
Video Mode function with the value of
screen-dimensions-nxm in the AL register.)
For example, suppose your adapter will switch to 66x80 dimensions when
put into video mode 85. Then you can make Emacs support this screen
size by putting the following into your _emacs file:
(setq screen-dimensions-66x80 85)
Since Emacs on MS-DOS can only set the frame size to specific supported dimensions, it cannot honor every possible frame resizing request. When an unsupported size is requested, Emacs chooses the next larger supported size beyond the specified size. For example, if you ask for 36x80 frame, you will get 40x80 instead.
The variables screen-dimensions-nxm are used only
when they exactly match the specified size; the search for the next
larger supported size ignores them. In the above example, even if your
VGA supports 38x80 dimensions and you define a variable
screen-dimensions-38x80 with a suitable value, you will still get
40x80 screen when you ask for a 36x80 frame. If you want to get the
38x80 size in this case, you can do it by setting the variable named
screen-dimensions-36x80 with the same video mode value as
screen-dimensions-38x80.
Changing frame dimensions on MS-DOS has the effect of changing all the other frames to the new dimensions.
MS-DOS normally uses a backslash, ‘\’, to separate name units within a file name, instead of the slash used on other systems. Emacs on MS-DOS permits use of either slash or backslash, and also knows about drive letters in file names.
On MS-DOS, file names are case-insensitive and limited to eight characters, plus optionally a period and three more characters. Emacs knows enough about these limitations to handle file names that were meant for other operating systems. For instance, leading dots ‘.’ in file names are invalid in MS-DOS, so Emacs transparently converts them to underscores ‘_’; thus your default init file (see Init File) is called _emacs on MS-DOS. Excess characters before or after the period are generally ignored by MS-DOS itself; thus, if you visit the file LongFileName.EvenLongerExtension, you will silently get longfile.eve, but Emacs will still display the long file name on the mode line. Other than that, it's up to you to specify file names which are valid under MS-DOS; the transparent conversion as described above only works on file names built into Emacs.
The above restrictions on the file names on MS-DOS make it almost impossible to construct the name of a backup file (see Backup Names) without losing some of the original file name characters. For example, the name of a backup file for docs.txt is docs.tx~ even if single backup is used.
If you run Emacs as a DOS application under Windows 9X, Windows ME, or Windows 2000, you can turn on support for long file names. If you do that, Emacs doesn't truncate file names or convert them to lower case; instead, it uses the file names that you specify, verbatim. To enable long file name support, set the environment variable LFN to ‘y’ before starting Emacs. Unfortunately, Windows NT doesn't allow DOS programs to access long file names, so Emacs built for MS-DOS will only see their short 8+3 aliases.
MS-DOS has no notion of home directory, so Emacs on MS-DOS pretends that the directory where it is installed is the value of the HOME environment variable. That is, if your Emacs binary, emacs.exe, is in the directory c:/utils/emacs/bin, then Emacs acts as if HOME were set to ‘c:/utils/emacs’. In particular, that is where Emacs looks for the init file _emacs. With this in mind, you can use ‘~’ in file names as an alias for the home directory, as you would on GNU or Unix. You can also set HOME variable in the environment before starting Emacs; its value will then override the above default behavior.
Emacs on MS-DOS handles the directory name /dev specially, because of a feature in the emulator libraries of DJGPP that pretends I/O devices have names in that directory. We recommend that you avoid using an actual directory named /dev on any disk.
GNU Emacs uses newline characters to separate text lines. This is the convention used on GNU and Unix.
MS-DOS and MS-Windows normally use carriage-return linefeed, a two-character sequence, to separate text lines. (Linefeed is the same character as newline.) Therefore, convenient editing of typical files with Emacs requires conversion of these end-of-line (EOL) sequences. And that is what Emacs normally does: it converts carriage-return linefeed into newline when reading files, and converts newline into carriage-return linefeed when writing files. The same mechanism that handles conversion of international character codes does this conversion also (see Coding Systems).
One consequence of this special format-conversion of most files is that character positions as reported by Emacs (see Position Info) do not agree with the file size information known to the operating system.
In addition, if Emacs recognizes from a file's contents that it uses newline rather than carriage-return linefeed as its line separator, it does not perform EOL conversion when reading or writing that file. Thus, you can read and edit files from GNU and Unix systems on MS-DOS with no special effort, and they will retain their Unix-style end-of-line convention after you edit them.
The mode line indicates whether end-of-line translation was used for the current buffer. If MS-DOS end-of-line translation is in use for the buffer, a backslash ‘\’ is displayed after the coding system mnemonic near the beginning of the mode line (see Mode Line). If no EOL translation was performed, the string ‘(Unix)’ is displayed instead of the backslash, to alert you that the file's EOL format is not the usual carriage-return linefeed.
To visit a file and specify whether it uses DOS-style or Unix-style
end-of-line, specify a coding system (see Specify Coding). For
example, C-x <RET> c unix <RET> C-x C-f foobar.txt
visits the file foobar.txt without converting the EOLs; if some
line ends with a carriage-return linefeed pair, Emacs will display
‘^M’ at the end of that line. Similarly, you can direct Emacs to
save a buffer in a specified EOL format with the C-x <RET> f
command. For example, to save a buffer with Unix EOL format, type
C-x <RET> f unix <RET> C-x C-s. If you visit a file
with DOS EOL conversion, then save it with Unix EOL format, that
effectively converts the file to Unix EOL style, like dos2unix.
When you use NFS or Samba to access file systems that reside on
computers using GNU or Unix systems, Emacs should not perform
end-of-line translation on any files in these file systems—not even
when you create a new file. To request this, designate these file
systems as untranslated file systems by calling the function
add-untranslated-filesystem. It takes one argument: the file
system name, including a drive letter and optionally a directory. For
example,
(add-untranslated-filesystem "Z:")
designates drive Z as an untranslated file system, and
(add-untranslated-filesystem "Z:\\foo")
designates directory \foo on drive Z as an untranslated file system.
Most often you would use add-untranslated-filesystem in your
_emacs file, or in site-start.el so that all the users at
your site get the benefit of it.
To countermand the effect of add-untranslated-filesystem, use
the function remove-untranslated-filesystem. This function takes
one argument, which should be a string just like the one that was used
previously with add-untranslated-filesystem.
Designating a file system as untranslated does not affect character set conversion, only end-of-line conversion. Essentially, it directs Emacs to create new files with the Unix-style convention of using newline at the end of a line. See Coding Systems.
Some kinds of files should not be converted at all, because their
contents are not really text. Therefore, Emacs on MS-DOS distinguishes
certain files as binary files. (This distinction is not part of
MS-DOS; it is made by Emacs only.) Binary files include executable
programs, compressed archives, etc. Emacs uses the file name to decide
whether to treat a file as binary: the variable
file-name-buffer-file-type-alist defines the file-name patterns
that indicate binary files. If a file name matches one of the patterns
for binary files (those whose associations are of the type
(pattern . t), Emacs reads and writes that file using the
no-conversion coding system (see Coding Systems) which turns
off all coding-system conversions, not only the EOL conversion.
file-name-buffer-file-type-alist also includes file-name patterns
for files which are known to be DOS-style text files with
carriage-return linefeed EOL format, such as CONFIG.SYS; Emacs
always writes those files with DOS-style EOLs.
If a file which belongs to an untranslated file system matches one of
the file-name patterns in file-name-buffer-file-type-alist, the
EOL conversion is determined by file-name-buffer-file-type-alist.
Printing commands, such as lpr-buffer (see Printing) and
ps-print-buffer (see PostScript) can work in MS-DOS and
MS-Windows by sending the output to one of the printer ports, if a
Posix-style lpr program is unavailable. The same Emacs
variables control printing on all systems, but in some cases they have
different default values on MS-DOS and MS-Windows.
If you want to use your local printer, printing on it in the usual DOS
manner, then set the Lisp variable lpr-command to "" (its
default value) and printer-name to the name of the printer
port—for example, "PRN", the usual local printer port (that's
the default), or "LPT2", or "COM1" for a serial printer.
You can also set printer-name to a file name, in which case
“printed” output is actually appended to that file. If you set
printer-name to "NUL", printed output is silently
discarded (sent to the system null device).
On MS-Windows, when the Windows network software is installed, you can
also use a printer shared by another machine by setting
printer-name to the UNC share name for that printer—for example,
"//joes_pc/hp4si". (It doesn't matter whether you use forward
slashes or backslashes here.) To find out the names of shared printers,
run the command ‘net view’ at a DOS command prompt to obtain a list
of servers, and ‘net view server-name’ to see the names of printers
(and directories) shared by that server. Alternatively, click the
‘Network Neighborhood’ icon on your desktop, and look for machines
which share their printers via the network.
If the printer doesn't appear in the output of ‘net view’, or
if setting printer-name to the UNC share name doesn't produce a
hardcopy on that printer, you can use the ‘net use’ command to
connect a local print port such as "LPT2" to the networked
printer. For example, typing net use LPT2:
\\joes_pc\hp4si23
causes Windows to capture the LPT2 port and redirect the printed
material to the printer connected to the machine joes_pc.
After this command, setting printer-name to "LPT2"
should produce the hardcopy on the networked printer.
With some varieties of Windows network software, you can instruct
Windows to capture a specific printer port such as "LPT2", and
redirect it to a networked printer via the Control Panel->Printers applet instead of ‘net use’.
Some printers expect DOS codepage encoding of non-ASCII text, even
though they are connected to a Windows machine which uses a different
encoding for the same locale. For example, in the Latin-1 locale, DOS
uses codepage 850 whereas Windows uses codepage 1252. See MS-DOS and MULE. When you print to such printers from Windows, you can use the
C-x RET c (universal-coding-system-argument) command before
M-x lpr-buffer; Emacs will then convert the text to the DOS
codepage that you specify. For example, C-x RET c cp850-dos RET
M-x lpr-region RET will print the region while converting it to the
codepage 850 encoding. You may need to create the cpnnn
coding system with M-x codepage-setup.
If you set printer-name to a file name, it's best to use an
absolute file name. Emacs changes the working directory according to
the default directory of the current buffer, so if the file name in
printer-name is relative, you will end up with several such
files, each one in the directory of the buffer from which the printing
was done.
The commands print-buffer and print-region call the
pr program, or use special switches to the lpr program, to
produce headers on each printed page. MS-DOS and MS-Windows don't
normally have these programs, so by default, the variable
lpr-headers-switches is set so that the requests to print page
headers are silently ignored. Thus, print-buffer and
print-region produce the same output as lpr-buffer and
lpr-region, respectively. If you do have a suitable pr
program (for example, from GNU Textutils), set
lpr-headers-switches to nil; Emacs will then call
pr to produce the page headers, and print the resulting output as
specified by printer-name.
Finally, if you do have an lpr work-alike, you can set the
variable lpr-command to "lpr". Then Emacs will use
lpr for printing, as on other systems. (If the name of the
program isn't lpr, set lpr-command to specify where to
find it.) The variable lpr-switches has its standard meaning
when lpr-command is not "". If the variable
printer-name has a string value, it is used as the value for the
-P option to lpr, as on Unix.
A parallel set of variables, ps-lpr-command,
ps-lpr-switches, and ps-printer-name (see PostScript Variables), defines how PostScript files should be printed. These
variables are used in the same way as the corresponding variables
described above for non-PostScript printing. Thus, the value of
ps-printer-name is used as the name of the device (or file) to
which PostScript output is sent, just as printer-name is used for
non-PostScript printing. (There are two distinct sets of variables in
case you have two printers attached to two different ports, and only one
of them is a PostScript printer.)
The default value of the variable ps-lpr-command is "",
which causes PostScript output to be sent to the printer port specified
by ps-printer-name, but ps-lpr-command can also be set to
the name of a program which will accept PostScript files. Thus, if you
have a non-PostScript printer, you can set this variable to the name of
a PostScript interpreter program (such as Ghostscript). Any switches
that need to be passed to the interpreter program are specified using
ps-lpr-switches. (If the value of ps-printer-name is a
string, it will be added to the list of switches as the value for the
-P option. This is probably only useful if you are using
lpr, so when using an interpreter typically you would set
ps-printer-name to something other than a string so it is
ignored.)
For example, to use Ghostscript for printing on an Epson printer connected to the ‘LPT2’ port, put this in your _emacs file:
(setq ps-printer-name t) ; Ghostscript doesn't understand -P
(setq ps-lpr-command "c:/gs/gs386")
(setq ps-lpr-switches '("-q" "-dNOPAUSE"
"-sDEVICE=epson"
"-r240x72"
"-sOutputFile=LPT2"
"-Ic:/gs"))
(This assumes that Ghostscript is installed in the "c:/gs" directory.)
For backwards compatibility, the value of dos-printer
(dos-ps-printer), if it has a value, overrides the value of
printer-name (ps-printer-name), on MS-DOS and MS-Windows
only.
Emacs on MS-DOS supports the same international character sets as it does on GNU, Unix and other platforms (see International), including coding systems for converting between the different character sets. However, due to incompatibilities between MS-DOS/MS-Windows and other systems, there are several DOS-specific aspects of this support that you should be aware of. This section describes these aspects.
The description below is largely specific to the MS-DOS port of Emacs, especially where it talks about practical implications for Emacs users. For other operating systems, see the code-pages.el package, which implements support for MS-DOS- and MS-Windows-specific encodings for all platforms other than MS-DOS.
MS-DOS is designed to support one character set of 256 characters at any given time, but gives you a variety of character sets to choose from. The alternative character sets are known as DOS codepages. Each codepage includes all 128 ASCII characters, but the other 128 characters (codes 128 through 255) vary from one codepage to another. Each DOS codepage is identified by a 3-digit number, such as 850, 862, etc.
In contrast to X, which lets you use several fonts at the same time, MS-DOS normally doesn't allow use of several codepages in a single session. MS-DOS was designed to load a single codepage at system startup, and require you to reboot in order to change it24. Much the same limitation applies when you run DOS executables on other systems such as MS-Windows.
If you invoke Emacs on MS-DOS with the ‘--unibyte’ option (see Initial Options), Emacs does not perform any conversion of non-ASCII characters. Instead, it reads and writes any non-ASCII characters verbatim, and sends their 8-bit codes to the display verbatim. Thus, unibyte Emacs on MS-DOS supports the current codepage, whatever it may be, but cannot even represent any other characters.
For multibyte operation on MS-DOS, Emacs needs to know which
characters the chosen DOS codepage can display. So it queries the
system shortly after startup to get the chosen codepage number, and
stores the number in the variable dos-codepage. Some systems
return the default value 437 for the current codepage, even though the
actual codepage is different. (This typically happens when you use the
codepage built into the display hardware.) You can specify a different
codepage for Emacs to use by setting the variable dos-codepage in
your init file.
Multibyte Emacs supports only certain DOS codepages: those which can display Far-Eastern scripts, like the Japanese codepage 932, and those that encode a single ISO 8859 character set.
The Far-Eastern codepages can directly display one of the MULE character sets for these countries, so Emacs simply sets up to use the appropriate terminal coding system that is supported by the codepage. The special features described in the rest of this section mostly pertain to codepages that encode ISO 8859 character sets.
For the codepages which correspond to one of the ISO character sets,
Emacs knows the character set name based on the codepage number. Emacs
automatically creates a coding system to support reading and writing
files that use the current codepage, and uses this coding system by
default. The name of this coding system is cpnnn, where
nnn is the codepage number.25
All the cpnnn coding systems use the letter ‘D’ (for
“DOS”) as their mode-line mnemonic. Since both the terminal coding
system and the default coding system for file I/O are set to the proper
cpnnn coding system at startup, it is normal for the mode
line on MS-DOS to begin with ‘-DD\-’. See Mode Line.
Far-Eastern DOS terminals do not use the cpnnn coding
systems, and thus their initial mode line looks like the Emacs default.
Since the codepage number also indicates which script you are using,
Emacs automatically runs set-language-environment to select the
language environment for that script (see Language Environments).
If a buffer contains a character belonging to some other ISO 8859 character set, not the one that the chosen DOS codepage supports, Emacs displays it using a sequence of ASCII characters. For example, if the current codepage doesn't have a glyph for the letter ‘ò’ (small ‘o’ with a grave accent), it is displayed as ‘{`o}’, where the braces serve as a visual indication that this is a single character. (This may look awkward for some non-Latin characters, such as those from Greek or Hebrew alphabets, but it is still readable by a person who knows the language.) Even though the character may occupy several columns on the screen, it is really still just a single character, and all Emacs commands treat it as one.
Not all characters in DOS codepages correspond to ISO 8859
characters—some are used for other purposes, such as box-drawing
characters and other graphics. Emacs maps these characters to two
special character sets called eight-bit-control and
eight-bit-graphic, and displays them as their IBM glyphs.
However, you should be aware that other systems might display these
characters differently, so you should avoid them in text that might be
copied to a different operating system, or even to another DOS machine
that uses a different codepage.
Emacs supports many other characters sets aside from ISO 8859, but it
cannot display them on MS-DOS. So if one of these multibyte characters
appears in a buffer, Emacs on MS-DOS displays them as specified by the
dos-unsupported-character-glyph variable; by default, this glyph
is an empty triangle. Use the C-u C-x = command to display the
actual code and character set of such characters. See Position Info.
By default, Emacs defines a coding system to support the current codepage. To define a coding system for some other codepage (e.g., to visit a file written on a DOS machine in another country), use the M-x codepage-setup command. It prompts for the 3-digit code of the codepage, with completion, then creates the coding system for the specified codepage. You can then use the new coding system to read and write files, but you must specify it explicitly for the file command when you want to use it (see Specify Coding).
These coding systems are also useful for visiting a file encoded using a DOS codepage, using Emacs running on some other operating system.
MS-Windows provides its own codepages, which are different from the DOS codepages for the same locale. For example, DOS codepage 850 supports the same character set as Windows codepage 1252; DOS codepage 855 supports the same character set as Windows codepage 1251, etc. The MS-Windows version of Emacs uses the current codepage for display when invoked with the ‘-nw’ option. Support for codepages in the Windows port of Emacs is part of the code-pages.el package.
Because MS-DOS is a single-process “operating system,” asynchronous subprocesses are not available. In particular, Shell mode and its variants do not work. Most Emacs features that use asynchronous subprocesses also don't work on MS-DOS, including Shell mode and GUD. When in doubt, try and see; commands that don't work output an error message saying that asynchronous processes aren't supported.
Compilation under Emacs with M-x compile, searching files with M-x grep and displaying differences between files with M-x diff do work, by running the inferior processes synchronously. This means you cannot do any more editing until the inferior process finishes.
Spell checking also works, by means of special support for synchronous
invocation of the ispell program. This is slower than the
asynchronous invocation on other platforms
Instead of the Shell mode, which doesn't work on MS-DOS, you can use the M-x eshell command. This invokes the Eshell package that implements a Posix-like shell entirely in Emacs Lisp.
By contrast, Emacs compiled as a native Windows application does support asynchronous subprocesses. See Windows Processes.
Printing commands, such as lpr-buffer (see Printing) and
ps-print-buffer (see PostScript), work in MS-DOS by sending
the output to one of the printer ports. See MS-DOS Printing.
When you run a subprocess synchronously on MS-DOS, make sure the program terminates and does not try to read keyboard input. If the program does not terminate on its own, you will be unable to terminate it, because MS-DOS provides no general way to terminate a process. Pressing C-c or C-<BREAK> might sometimes help in these cases.
Accessing files on other machines is not supported on MS-DOS. Other network-oriented commands such as sending mail, Web browsing, remote login, etc., don't work either, unless network access is built into MS-DOS with some network redirector.
Dired on MS-DOS uses the ls-lisp package where other
platforms use the system ls command. Therefore, Dired on
MS-DOS supports only some of the possible options you can mention in
the dired-listing-switches variable. The options that work are
‘-A’, ‘-a’, ‘-c’, ‘-i’, ‘-r’, ‘-S’,
‘-s’, ‘-t’, and ‘-u’.
Emacs compiled as a native Windows application (as opposed to the DOS version) includes full support for asynchronous subprocesses. In the Windows version, synchronous and asynchronous subprocesses work fine on both Windows 9X and Windows NT/2K as long as you run only 32-bit Windows applications. However, when you run a DOS application in a subprocess, you may encounter problems or be unable to run the application at all; and if you run two DOS applications at the same time in two subprocesses, you may have to reboot your system.
Since the standard command interpreter (and most command line utilities) on Windows 95 are DOS applications, these problems are significant when using that system. But there's nothing we can do about them; only Microsoft can fix them.
If you run just one DOS application subprocess, the subprocess should work as expected as long as it is “well-behaved” and does not perform direct screen access or other unusual actions. If you have a CPU monitor application, your machine will appear to be 100% busy even when the DOS application is idle, but this is only an artifact of the way CPU monitors measure processor load.
You must terminate the DOS application before you start any other DOS application in a different subprocess. Emacs is unable to interrupt or terminate a DOS subprocess. The only way you can terminate such a subprocess is by giving it a command that tells its program to exit.
If you attempt to run two DOS applications at the same time in separate subprocesses, the second one that is started will be suspended until the first one finishes, even if either or both of them are asynchronous.
If you can go to the first subprocess, and tell it to exit, the second subprocess should continue normally. However, if the second subprocess is synchronous, Emacs itself will be hung until the first subprocess finishes. If it will not finish without user input, then you have no choice but to reboot if you are running on Windows 9X. If you are running on Windows NT/2K, you can use a process viewer application to kill the appropriate instance of ntvdm instead (this will terminate both DOS subprocesses).
If you have to reboot Windows 9X in this situation, do not use the
Shutdown command on the Start menu; that usually hangs the
system. Instead, type CTL-ALT-<DEL> and then choose
Shutdown. That usually works, although it may take a few minutes
to do its job.
Emacs compiled as a native Windows application normally turns off the Windows feature that tapping the <ALT> key invokes the Windows menu. The reason is that the <ALT> also serves as <META> in Emacs. When using Emacs, users often press the <META> key temporarily and then change their minds; if this has the effect of bringing up the Windows menu, it alters the meaning of subsequent commands. Many users find this frustrating.
You can re-enable Windows' default handling of tapping the <ALT> key
by setting w32-pass-alt-to-system to a non-nil value.
The GNU Manifesto which appears below was written by Richard Stallman at the beginning of the GNU project, to ask for participation and support. For the first few years, it was updated in minor ways to account for developments, but now it seems best to leave it unchanged as most people have seen it.Since that time, we have learned about certain common misunderstandings that different wording could help avoid. Footnotes added in 1993 help clarify these points.
For up-to-date information about the available GNU software, please see http://www.gnu.org. For software tasks to work on, see http://savannah.gnu.org/projects/tasklist. For other ways to contribute, see http://www.gnu.org/help.
GNU, which stands for Gnu's Not Unix, is the name for the complete Unix-compatible software system which I am writing so that I can give it away free to everyone who can use it.26 Several other volunteers are helping me. Contributions of time, money, programs and equipment are greatly needed.
So far we have an Emacs text editor with Lisp for writing editor commands, a source level debugger, a yacc-compatible parser generator, a linker, and around 35 utilities. A shell (command interpreter) is nearly completed. A new portable optimizing C compiler has compiled itself and may be released this year. An initial kernel exists but many more features are needed to emulate Unix. When the kernel and compiler are finished, it will be possible to distribute a GNU system suitable for program development. We will use TeX as our text formatter, but an nroff is being worked on. We will use the free, portable X window system as well. After this we will add a portable Common Lisp, an Empire game, a spreadsheet, and hundreds of other things, plus on-line documentation. We hope to supply, eventually, everything useful that normally comes with a Unix system, and more.
GNU will be able to run Unix programs, but will not be identical to Unix. We will make all improvements that are convenient, based on our experience with other operating systems. In particular, we plan to have longer file names, file version numbers, a crashproof file system, file name completion perhaps, terminal-independent display support, and perhaps eventually a Lisp-based window system through which several Lisp programs and ordinary Unix programs can share a screen. Both C and Lisp will be available as system programming languages. We will try to support UUCP, MIT Chaosnet, and Internet protocols for communication.
GNU is aimed initially at machines in the 68000/16000 class with virtual memory, because they are the easiest machines to make it run on. The extra effort to make it run on smaller machines will be left to someone who wants to use it on them.
To avoid horrible confusion, please pronounce the `G' in the word `GNU' when it is the name of this project.
I consider that the golden rule requires that if I like a program I must share it with other people who like it. Software sellers want to divide the users and conquer them, making each user agree not to share with others. I refuse to break solidarity with other users in this way. I cannot in good conscience sign a nondisclosure agreement or a software license agreement. For years I worked within the Artificial Intelligence Lab to resist such tendencies and other inhospitalities, but eventually they had gone too far: I could not remain in an institution where such things are done for me against my will.
So that I can continue to use computers without dishonor, I have decided to put together a sufficient body of free software so that I will be able to get along without any software that is not free. I have resigned from the AI lab to deny MIT any legal excuse to prevent me from giving GNU away.
Unix is not my ideal system, but it is not too bad. The essential features of Unix seem to be good ones, and I think I can fill in what Unix lacks without spoiling them. And a system compatible with Unix would be convenient for many other people to adopt.
GNU is not in the public domain. Everyone will be permitted to modify and redistribute GNU, but no distributor will be allowed to restrict its further redistribution. That is to say, proprietary modifications will not be allowed. I want to make sure that all versions of GNU remain free.
I have found many other programmers who are excited about GNU and want to help.
Many programmers are unhappy about the commercialization of system software. It may enable them to make more money, but it requires them to feel in conflict with other programmers in general rather than feel as comrades. The fundamental act of friendship among programmers is the sharing of programs; marketing arrangements now typically used essentially forbid programmers to treat others as friends. The purchaser of software must choose between friendship and obeying the law. Naturally, many decide that friendship is more important. But those who believe in law often do not feel at ease with either choice. They become cynical and think that programming is just a way of making money.
By working on and using GNU rather than proprietary programs, we can be hospitable to everyone and obey the law. In addition, GNU serves as an example to inspire and a banner to rally others to join us in sharing. This can give us a feeling of harmony which is impossible if we use software that is not free. For about half the programmers I talk to, this is an important happiness that money cannot replace.
I am asking computer manufacturers for donations of machines and money. I'm asking individuals for donations of programs and work.
One consequence you can expect if you donate machines is that GNU will run on them at an early date. The machines should be complete, ready to use systems, approved for use in a residential area, and not in need of sophisticated cooling or power.
I have found very many programmers eager to contribute part-time work for GNU. For most projects, such part-time distributed work would be very hard to coordinate; the independently-written parts would not work together. But for the particular task of replacing Unix, this problem is absent. A complete Unix system contains hundreds of utility programs, each of which is documented separately. Most interface specifications are fixed by Unix compatibility. If each contributor can write a compatible replacement for a single Unix utility, and make it work properly in place of the original on a Unix system, then these utilities will work right when put together. Even allowing for Murphy to create a few unexpected problems, assembling these components will be a feasible task. (The kernel will require closer communication and will be worked on by a small, tight group.)
If I get donations of money, I may be able to hire a few people full or part time. The salary won't be high by programmers' standards, but I'm looking for people for whom building community spirit is as important as making money. I view this as a way of enabling dedicated people to devote their full energies to working on GNU by sparing them the need to make a living in another way.
Once GNU is written, everyone will be able to obtain good system software free, just like air.27
This means much more than just saving everyone the price of a Unix license. It means that much wasteful duplication of system programming effort will be avoided. This effort can go instead into advancing the state of the art.
Complete system sources will be available to everyone. As a result, a user who needs changes in the system will always be free to make them himself, or hire any available programmer or company to make them for him. Users will no longer be at the mercy of one programmer or company which owns the sources and is in sole position to make changes.
Schools will be able to provide a much more educational environment by encouraging all students to study and improve the system code. Harvard's computer lab used to have the policy that no program could be installed on the system if its sources were not on public display, and upheld it by actually refusing to install certain programs. I was very much inspired by this.
Finally, the overhead of considering who owns the system software and what one is or is not entitled to do with it will be lifted.
Arrangements to make people pay for using a program, including licensing of copies, always incur a tremendous cost to society through the cumbersome mechanisms necessary to figure out how much (that is, which programs) a person must pay for. And only a police state can force everyone to obey them. Consider a space station where air must be manufactured at great cost: charging each breather per liter of air may be fair, but wearing the metered gas mask all day and all night is intolerable even if everyone can afford to pay the air bill. And the TV cameras everywhere to see if you ever take the mask off are outrageous. It's better to support the air plant with a head tax and chuck the masks.
Copying all or parts of a program is as natural to a programmer as breathing, and as productive. It ought to be as free.
“Nobody will use it if it is free, because that means they can't rely on any support.”“You have to charge for the program to pay for providing the support.”
If people would rather pay for GNU plus service than get GNU free without service, a company to provide just service to people who have obtained GNU free ought to be profitable.28
We must distinguish between support in the form of real programming work and mere handholding. The former is something one cannot rely on from a software vendor. If your problem is not shared by enough people, the vendor will tell you to get lost.
If your business needs to be able to rely on support, the only way is to have all the necessary sources and tools. Then you can hire any available person to fix your problem; you are not at the mercy of any individual. With Unix, the price of sources puts this out of consideration for most businesses. With GNU this will be easy. It is still possible for there to be no available competent person, but this problem cannot be blamed on distribution arrangements. GNU does not eliminate all the world's problems, only some of them.
Meanwhile, the users who know nothing about computers need handholding: doing things for them which they could easily do themselves but don't know how.
Such services could be provided by companies that sell just hand-holding and repair service. If it is true that users would rather spend money and get a product with service, they will also be willing to buy the service having got the product free. The service companies will compete in quality and price; users will not be tied to any particular one. Meanwhile, those of us who don't need the service should be able to use the program without paying for the service.
“You cannot reach many people without advertising, and you must charge for the program to support that.”“It's no use advertising a program people can get free.”
There are various forms of free or very cheap publicity that can be used to inform numbers of computer users about something like GNU. But it may be true that one can reach more microcomputer users with advertising. If this is really so, a business which advertises the service of copying and mailing GNU for a fee ought to be successful enough to pay for its advertising and more. This way, only the users who benefit from the advertising pay for it.
On the other hand, if many people get GNU from their friends, and such companies don't succeed, this will show that advertising was not really necessary to spread GNU. Why is it that free market advocates don't want to let the free market decide this?29
“My company needs a proprietary operating system to get a competitive edge.”
GNU will remove operating system software from the realm of competition. You will not be able to get an edge in this area, but neither will your competitors be able to get an edge over you. You and they will compete in other areas, while benefiting mutually in this one. If your business is selling an operating system, you will not like GNU, but that's tough on you. If your business is something else, GNU can save you from being pushed into the expensive business of selling operating systems.
I would like to see GNU development supported by gifts from many manufacturers and users, reducing the cost to each.30
“Don't programmers deserve a reward for their creativity?”
If anything deserves a reward, it is social contribution. Creativity can be a social contribution, but only in so far as society is free to use the results. If programmers deserve to be rewarded for creating innovative programs, by the same token they deserve to be punished if they restrict the use of these programs.
“Shouldn't a programmer be able to ask for a reward for his creativity?”
There is nothing wrong with wanting pay for work, or seeking to maximize one's income, as long as one does not use means that are destructive. But the means customary in the field of software today are based on destruction.
Extracting money from users of a program by restricting their use of it is destructive because the restrictions reduce the amount and the ways that the program can be used. This reduces the amount of wealth that humanity derives from the program. When there is a deliberate choice to restrict, the harmful consequences are deliberate destruction.
The reason a good citizen does not use such destructive means to become wealthier is that, if everyone did so, we would all become poorer from the mutual destructiveness. This is Kantian ethics; or, the Golden Rule. Since I do not like the consequences that result if everyone hoards information, I am required to consider it wrong for one to do so. Specifically, the desire to be rewarded for one's creativity does not justify depriving the world in general of all or part of that creativity.
“Won't programmers starve?”
I could answer that nobody is forced to be a programmer. Most of us cannot manage to get any money for standing on the street and making faces. But we are not, as a result, condemned to spend our lives standing on the street making faces, and starving. We do something else.
But that is the wrong answer because it accepts the questioner's implicit assumption: that without ownership of software, programmers cannot possibly be paid a cent. Supposedly it is all or nothing.
The real reason programmers will not starve is that it will still be possible for them to get paid for programming; just not paid as much as now.
Restricting copying is not the only basis for business in software. It is the most common basis because it brings in the most money. If it were prohibited, or rejected by the customer, software business would move to other bases of organization which are now used less often. There are always numerous ways to organize any kind of business.
Probably programming will not be as lucrative on the new basis as it is now. But that is not an argument against the change. It is not considered an injustice that sales clerks make the salaries that they now do. If programmers made the same, that would not be an injustice either. (In practice they would still make considerably more than that.)
“Don't people have a right to control how their creativity is used?”
“Control over the use of one's ideas” really constitutes control over other people's lives; and it is usually used to make their lives more difficult.
People who have studied the issue of intellectual property rights31 carefully (such as lawyers) say that there is no intrinsic right to intellectual property. The kinds of supposed intellectual property rights that the government recognizes were created by specific acts of legislation for specific purposes.
For example, the patent system was established to encourage inventors to disclose the details of their inventions. Its purpose was to help society rather than to help inventors. At the time, the life span of 17 years for a patent was short compared with the rate of advance of the state of the art. Since patents are an issue only among manufacturers, for whom the cost and effort of a license agreement are small compared with setting up production, the patents often do not do much harm. They do not obstruct most individuals who use patented products.
The idea of copyright did not exist in ancient times, when authors frequently copied other authors at length in works of non-fiction. This practice was useful, and is the only way many authors' works have survived even in part. The copyright system was created expressly for the purpose of encouraging authorship. In the domain for which it was invented—books, which could be copied economically only on a printing press—it did little harm, and did not obstruct most of the individuals who read the books.
All intellectual property rights are just licenses granted by society because it was thought, rightly or wrongly, that society as a whole would benefit by granting them. But in any particular situation, we have to ask: are we really better off granting such license? What kind of act are we licensing a person to do?
The case of programs today is very different from that of books a hundred years ago. The fact that the easiest way to copy a program is from one neighbor to another, the fact that a program has both source code and object code which are distinct, and the fact that a program is used rather than read and enjoyed, combine to create a situation in which a person who enforces a copyright is harming society as a whole both materially and spiritually; in which a person should not do so regardless of whether the law enables him to.
“Competition makes things get done better.”
The paradigm of competition is a race: by rewarding the winner, we encourage everyone to run faster. When capitalism really works this way, it does a good job; but its defenders are wrong in assuming it always works this way. If the runners forget why the reward is offered and become intent on winning, no matter how, they may find other strategies—such as, attacking other runners. If the runners get into a fist fight, they will all finish late.
Proprietary and secret software is the moral equivalent of runners in a fist fight. Sad to say, the only referee we've got does not seem to object to fights; he just regulates them (“For every ten yards you run, you can fire one shot”). He really ought to break them up, and penalize runners for even trying to fight.
“Won't everyone stop programming without a monetary incentive?”
Actually, many people will program with absolutely no monetary incentive. Programming has an irresistible fascination for some people, usually the people who are best at it. There is no shortage of professional musicians who keep at it even though they have no hope of making a living that way.
But really this question, though commonly asked, is not appropriate to the situation. Pay for programmers will not disappear, only become less. So the right question is, will anyone program with a reduced monetary incentive? My experience shows that they will.
For more than ten years, many of the world's best programmers worked at the Artificial Intelligence Lab for far less money than they could have had anywhere else. They got many kinds of non-monetary rewards: fame and appreciation, for example. And creativity is also fun, a reward in itself.
Then most of them left when offered a chance to do the same interesting work for a lot of money.
What the facts show is that people will program for reasons other than riches; but if given a chance to make a lot of money as well, they will come to expect and demand it. Low-paying organizations do poorly in competition with high-paying ones, but they do not have to do badly if the high-paying ones are banned.
“We need the programmers desperately. If they demand that we stop helping our neighbors, we have to obey.”
You're never so desperate that you have to obey this sort of demand. Remember: millions for defense, but not a cent for tribute!
“Programmers need to make a living somehow.”
In the short run, this is true. However, there are plenty of ways that programmers could make a living without selling the right to use a program. This way is customary now because it brings programmers and businessmen the most money, not because it is the only way to make a living. It is easy to find other ways if you want to find them. Here are a number of examples.
A manufacturer introducing a new computer will pay for the porting of operating systems onto the new hardware.
The sale of teaching, hand-holding and maintenance services could also employ programmers.
People with new ideas could distribute programs as freeware32, asking for donations from satisfied users, or selling hand-holding services. I have met people who are already working this way successfully.
Users with related needs can form users' groups, and pay dues. A group would contract with programming companies to write programs that the group's members would like to use.
All sorts of development can be funded with a Software Tax:
Suppose everyone who buys a computer has to pay x percent of the price as a software tax. The government gives this to an agency like the NSF to spend on software development.But if the computer buyer makes a donation to software development himself, he can take a credit against the tax. He can donate to the project of his own choosing—often, chosen because he hopes to use the results when it is done. He can take a credit for any amount of donation up to the total tax he had to pay.
The total tax rate could be decided by a vote of the payers of the tax, weighted according to the amount they will be taxed on.
The consequences:
- The computer-using community supports software development.
- This community decides what level of support is needed.
- Users who care which projects their share is spent on can choose this for themselves.
In the long run, making programs free is a step toward the post-scarcity world, where nobody will have to work very hard just to make a living. People will be free to devote themselves to activities that are fun, such as programming, after spending the necessary ten hours a week on required tasks such as legislation, family counseling, robot repair and asteroid prospecting. There will be no need to be able to make a living from programming.
We have already greatly reduced the amount of work that the whole society must do for its actual productivity, but only a little of this has translated itself into leisure for workers because much nonproductive activity is required to accompany productive activity. The main causes of this are bureaucracy and isometric struggles against competition. Free software will greatly reduce these drains in the area of software production. We must do this, in order for technical gains in productivity to translate into less work for us.
The particular form of copyleft used by the GNU project is called the
GNU General Public License. See Copying.
defun. See Defuns.
Some people use the term “pathname” for file names, but we do not;
we use the word “path” only in the term “search path” (q.v.).
fringe. See fringe.
Emacs uses highlighting in several ways. When you mark a region with
the mouse, the region is always highlighted. Optionally Emacs can
also highlight the region whenever it is active (see Transient Mark). Incremental search also highlights matches (see Incremental Search). See also `font lock'.
next-line. See Keymaps.
On some terminals, the <META> key is actually labeled <ALT>
or <EDIT>.
nilnil is a value usually interpreted as a logical “false.” Its
opposite is t, interpreted as “true.”
The Emacs kill commands set the primary selection and the yank command
uses the primary selection when appropriate. See Killing.
load-path
holds a search path for finding Lisp library files. See Lisp Libraries.
Many people have contributed code included in the Free Software Foundation's distribution of GNU Emacs. To show our appreciation for their public spirit, we list here in alphabetical order those who have written substantial portions.
diff
output.
locate command,
find program,
eldoc-mode, a mode to show the defined parameters or
the doc string for the Lisp function near point. With Roland McGrath,
he wrote rsz-mini.el, a minor mode to automatically resize the
minibuffer to fit the text it contains.
Calc, an advanced calculator and mathematical tool,
alloca implementation.
intangible text property, and rearranged the structure of the
Lisp_Object type to allow for more data bits.
refer (the troff
version) and lookbib, and refbib.el, a package to convert
those databases to the format used by the LaTeX text formatting package.
dired-mode, with contributions
by Lawrence R. Dodd. He also wrote ls-lisp.el, a Lisp emulation
of the ls command for platforms which don't have ls as a
standard program.
edebug debug code
written using David Gillespie's Common Lisp support,
eval-region in Emacs
Lisp, and
ps-print, a package for pretty-printing Emacs buffers to
PostScript printers,
autoarg-mode, a global minor mode whereby digit keys supply
prefix arguments, and autoarg-kp-mode which redefines the keypad
numeric keys to digit arguments,
calendar package.
#ifdef clauses.
dired commands on output from the
find program, with Sebastian Kremer,
ebrowse C++ browser,
PCL-CVS, a directory-level front end to the CVS version control
system,
diff3
conflicts, and
mailto:
URLs.
xwsh and winterm terminal emulators.
Daniel also rewrote apropos.el, originally written by Joe Wells, and, together with Jim Blandy, co-authored wyse50.el, support for Wyse 50 terminals.
etags program.
load-history lisp variable, which
records the source file from which each lisp function loaded into Emacs
came.
telnet
sessions within Emacs.
open-network-stream function for
some Emacs configurations which lack it, and
He also helped port Emacs to MS-DOS.
eshell, a command shell implemented entirely in Emacs Lisp.
mbox format.
WoMan, a package for browsing
manual pages without the man command.
cantReadThisVariable, and
tildify.el, commands for adding hard spaces to text, TeX, and
SGML/HTML files.
Others too numerous to mention have reported and fixed bugs, and added features to many parts of Emacs. (Many are mentioned in the ChangeLog files which are summarized in the file AUTHORS in the distribution.) We thank them for their generosity as well.
This list intended to mention every contributor of a major package or feature we currently distribute; if you know of someone we have omitted, please report that as a manual bug.
! (Dired): Shell Commands in Dired" (TeX mode): TeX Editing# (Dired): Flagging Many Files$ (Dired): Hiding Subdirectories% C (Dired): Transforming File Names% d (Dired): Flagging Many Files% g (Dired): Marks vs Flags% H (Dired): Transforming File Names% l (Dired): Transforming File Names% m (Dired): Marks vs Flags% R (Dired): Transforming File Names% S (Dired): Transforming File Names% u (Dired): Transforming File Names& (Dired): Flagging Many Files* ! (Dired): Marks vs Flags* % (Dired): Marks vs Flags* * (Dired): Marks vs Flags* / (Dired): Marks vs Flags* ? (Dired): Marks vs Flags* @ (Dired): Marks vs Flags* c (Dired): Marks vs Flags* C-n (Dired): Marks vs Flags* C-p (Dired): Marks vs Flags* DEL (Dired): Marks vs Flags* m (Dired): Marks vs Flags* s (Dired): Marks vs Flags* t (Dired): Marks vs Flags* u (Dired): Marks vs Flags+ (Dired): Operating on Files. (Calendar mode): Specified Dates. (Dired): Flagging Many Files. (Rmail): Rmail Scrolling< (Calendar mode): Scroll Calendar< (Dired): Subdirectory Motion< (Rmail): Rmail Motion<TAB> (Help mode): Help Mode= (Dired): Comparison in Dired> (Calendar mode): Scroll Calendar> (Dired): Subdirectory Motion> (Rmail): Rmail Motion^ (Dired): Dired Visitinga (Calendar mode): HolidaysA (Dired): Operating on Filesa (Rmail): Rmail LabelsB (Dired): Operating on Filesb (Rmail): Rmail BasicsBACKSPACE: DeletionBS: DeletionBS (MS-DOS): MS-DOS KeyboardC (Dired): Operating on Filesc (Rmail): Rmail ReplyC-/: UndoC-<SPC> C-<SPC>: Momentary MarkC-<TAB>: File Name CacheC-@: Setting MarkC-\: Select Input MethodC-]: QuittingC-_: UndoC-_ (Dired): Marks vs FlagsC-a: Moving PointC-a (Calendar mode): Move to Beginning or EndC-b: Moving PointC-b (Calendar mode): Calendar Unit MotionC-BREAK (MS-DOS): MS-DOS KeyboardC-c ' (Picture mode): Insert in PictureC-c . (C mode): Custom C IndentC-c . (Picture mode): Insert in PictureC-c . (Shell mode): Shell RingC-c / (Picture mode): Insert in PictureC-c / (SGML mode): HTML ModeC-c 8 (SGML mode): HTML ModeC-c ; (Fortran mode): Fortran CommentsC-c < (GUD): Commands of GUDC-c < (Picture mode): Insert in PictureC-c <BS> (C Mode): Hungry DeleteC-c <DEL> (C Mode): Hungry DeleteC-c > (GUD): Commands of GUDC-c > (Picture mode): Insert in PictureC-c ? (SGML mode): HTML ModeC-c @ (Outline minor mode): Outline ModeC-c @ C-h: HideshowC-c @ C-l: HideshowC-c @ C-M-h: HideshowC-c @ C-M-s: HideshowC-c @ C-r: HideshowC-c @ C-s: HideshowC-c [ (Enriched mode): Format IndentationC-c \ (Picture mode): Insert in PictureC-c ] (Enriched mode): Format IndentationC-c ^ (Picture mode): Insert in PictureC-c ` (Picture mode): Insert in PictureC-c C-<BS> (C Mode): Hungry DeleteC-c C-<DEL> (C Mode): Hungry DeleteC-c C-\ (C mode): Other C CommandsC-c C-\ (Shell mode): Shell ModeC-c C-a (C mode): Electric CC-c C-a (F90 mode): Fortran MotionC-c C-a (Mail mode): Mail AliasesC-c C-a (Outline mode): Outline VisibilityC-c C-a (SGML mode): HTML ModeC-c C-a (Shell mode): Shell ModeC-c C-b (Outline mode): Outline MotionC-c C-b (Picture mode): Insert in PictureC-c C-b (SGML mode): HTML ModeC-c C-b (Shell mode): Shell ModeC-c C-b (TeX mode): TeX PrintC-c C-c (C mode): Multi-Line CommentsC-c C-c (Edit Abbrevs): Editing AbbrevsC-c C-c (Edit Tab Stops): Tab StopsC-c C-c (Mail mode): Mail SendingC-c C-c (Outline mode): Outline VisibilityC-c C-c (Shell mode): Shell ModeC-c C-c (TeX mode): TeX PrintC-c C-d (C Mode): Hungry DeleteC-c C-d (Fortran mode): ForIndent CommandsC-c C-d (GUD): Commands of GUDC-c C-d (Outline mode): Outline VisibilityC-c C-d (Picture mode): Basic PictureC-c C-d (SGML mode): HTML ModeC-c C-e (C mode): Other C CommandsC-c C-e (F90 mode): Fortran MotionC-c C-e (LaTeX mode): LaTeX EditingC-c C-e (Outline mode): Outline VisibilityC-c C-e (Shell mode): Shell ModeC-c C-f (GUD): Commands of GUDC-c C-f (Outline mode): Outline MotionC-c C-f (Picture mode): Insert in PictureC-c C-f (SGML mode): HTML ModeC-c C-f (Shell mode): Shell ModeC-c C-f (TeX mode): TeX PrintC-c C-f C-b (Mail mode): Header EditingC-c C-f C-c (Mail mode): Header EditingC-c C-f C-f (Mail mode): Header EditingC-c C-f C-s (Mail mode): Header EditingC-c C-f C-t (Mail mode): Header EditingC-c C-i (GUD): Commands of GUDC-c C-i (Mail mode): Mail Mode MiscC-c C-i (Outline mode): Outline VisibilityC-c C-j (Term mode): Term ModeC-c C-k (Outline mode): Outline VisibilityC-c C-k (Picture mode): Rectangles in PictureC-c C-k (Term mode): Term ModeC-c C-k (TeX mode): TeX PrintC-c C-l (C mode): Electric CC-c C-l (Calendar mode): General CalendarC-c C-l (GUD): Commands of GUDC-c C-l (Outline mode): Outline VisibilityC-c C-l (Shell mode): Shell RingC-c C-l (TeX mode): TeX PrintC-c C-n (C mode): Motion in CC-c C-n (Fortran mode): Fortran MotionC-c C-n (GUD): Commands of GUDC-c C-n (Outline mode): Outline MotionC-c C-n (SGML mode): HTML ModeC-c C-n (Shell mode): Shell History CopyingC-c C-o (LaTeX mode): LaTeX EditingC-c C-o (Outline mode): Outline VisibilityC-c C-o (Shell mode): Shell ModeC-c C-p (C mode): Motion in CC-c C-p (Fortran mode): Fortran MotionC-c C-p (Outline mode): Outline MotionC-c C-p (Shell mode): Shell History CopyingC-c C-p (TeX mode): TeX PrintC-c C-q (C mode): C IndentC-c C-q (Mail mode): Citing MailC-c C-q (Outline mode): Outline VisibilityC-c C-q (Term mode): Paging in TermC-c C-q (TeX mode): TeX PrintC-c C-r (Fortran mode): Fortran ColumnsC-c C-r (GUD): Commands of GUDC-c C-r (Mail mode): Citing MailC-c C-r (Shell mode): Shell ModeC-c C-r (TeX mode): TeX PrintC-c C-s (C mode): Other C CommandsC-c C-s (GUD): Commands of GUDC-c C-s (Mail mode): Mail SendingC-c C-s (Outline mode): Outline VisibilityC-c C-s (Shell mode): Shell ModeC-c C-t (GUD): Commands of GUDC-c C-t (Mail mode): Mail Mode MiscC-c C-t (Outline mode): Outline VisibilityC-c C-t (SGML mode): HTML ModeC-c C-u (C mode): Motion in CC-c C-u (GUD): Commands of GUDC-c C-u (Outline mode): Outline MotionC-c C-u (Shell mode): Shell ModeC-c C-v (SGML mode): HTML ModeC-c C-v (TeX mode): TeX PrintC-c C-w (Fortran mode): Fortran ColumnsC-c C-w (Mail mode): Mail Mode MiscC-c C-w (Picture mode): Rectangles in PictureC-c C-w (Shell mode): Shell ModeC-c C-x: FoldoutC-c C-x (Picture mode): Rectangles in PictureC-c C-x (Shell mode): Shell RingC-c C-y (Mail mode): Citing MailC-c C-y (Picture mode): Rectangles in PictureC-c C-z: FoldoutC-c C-z (Shell mode): Shell ModeC-c RET (Shell mode): Shell History CopyingC-c TAB (Picture mode): Tabs in PictureC-c TAB (SGML mode): HTML ModeC-c TAB (TeX mode): TeX PrintC-c { (TeX mode): TeX EditingC-c } (TeX mode): TeX EditingC-d: DeletionC-d (Rmail): Rmail DeletionC-d (Shell mode): Shell ModeC-Down-Mouse-1: Buffer MenusC-e: Moving PointC-e (Calendar mode): Move to Beginning or EndC-f: Moving PointC-f (Calendar mode): Calendar Unit MotionC-g: QuittingC-g (MS-DOS): MS-DOS KeyboardC-h: HelpC-h .: Help EchoC-h a: AproposC-h b: Misc HelpC-h C: Coding SystemsC-h c: Key HelpC-h C-\: Select Input MethodC-h C-c: Help FilesC-h C-d: Help FilesC-h C-e: Help FilesC-h C-f: Help FilesC-h C-h: HelpC-h C-n: Help FilesC-h C-p: Help FilesC-h C-t: Help FilesC-h C-w: Help FilesC-h d: AproposC-h e: Misc HelpC-h F: Misc HelpC-h f: Name HelpC-h h: International CharsC-h I: Select Input MethodC-h i: Misc HelpC-h K: Misc HelpC-h k: Key HelpC-h L: Language EnvironmentsC-h l: Misc HelpC-h m: Misc HelpC-h p: Library KeywordsC-h s: SyntaxC-h S: Info LookupC-h S: Misc HelpC-h t: BasicC-h w: Key HelpC-j: Basic IndentC-j (and major modes): Major ModesC-j (MS-DOS): MS-DOS KeyboardC-j (TeX mode): TeX EditingC-k: Killing by LinesC-k (Gnus): Summary of GnusC-l: ScrollingC-M-%: Query ReplaceC-M-.: Find TagC-M-/: Dynamic AbbrevsC-M-<SPC>: ExpressionsC-M-@: ExpressionsC-M-\: Indentation CommandsC-M-a: Moving by DefunsC-M-b: ExpressionsC-M-c: Recursive EditC-M-d: Moving by ParensC-M-d (Dired): Subdirectory MotionC-M-e: Moving by DefunsC-M-f: ExpressionsC-M-h: Moving by DefunsC-M-h (C mode): Moving by DefunsC-M-j: Multi-Line CommentsC-M-j (Fortran mode): ForIndent CommandsC-M-k: ExpressionsC-M-l: ScrollingC-M-l (Rmail): Rmail Make SummaryC-M-l (Shell mode): Shell ModeC-M-n: Moving by ParensC-M-n (Dired): Subdirectory MotionC-M-n (Fortran mode): Fortran MotionC-M-n (Rmail): Rmail LabelsC-M-o: Indentation CommandsC-M-p: Moving by ParensC-M-p (Dired): Subdirectory MotionC-M-p (Fortran mode): Fortran MotionC-M-p (Rmail): Rmail LabelsC-M-q: Multi-line IndentC-M-q (C mode): C IndentC-M-q (Fortran mode): ForIndent CommandsC-M-r: Regexp SearchC-M-r (Rmail): Rmail Make SummaryC-M-s: Regexp SearchC-M-s (Rmail): Rmail Make SummaryC-M-t: ExpressionsC-M-t (Rmail): Rmail Make SummaryC-M-u: Moving by ParensC-M-u (Dired): Subdirectory MotionC-M-v: Other WindowC-M-w: Appending KillsC-M-x (Emacs-Lisp mode): Lisp EvalC-M-x (Lisp mode): External LispC-Mouse-1: Menu Mouse ClicksC-Mouse-2: Menu Mouse ClicksC-mouse-2 (mode line): Mode Line MouseC-Mouse-2 (scroll bar): Mode Line MouseC-Mouse-2 (scroll bar): Split WindowC-Mouse-3: Menu Mouse ClicksC-Mouse-3 (when menu bar is disabled): Menu BarsC-n: Moving PointC-n (Calendar mode): Calendar Unit MotionC-n (Dired): Dired NavigationC-n (Gnus Group mode): Summary of GnusC-n (Gnus Summary mode): Summary of GnusC-o: Blank LinesC-o (Dired): Dired VisitingC-o (Occur mode): Other Repeating SearchC-o (Rmail): Rmail OutputC-p: Moving PointC-p (Calendar mode): Calendar Unit MotionC-p (Dired): Dired NavigationC-p (Gnus Group mode): Summary of GnusC-p (Gnus Summary mode): Summary of GnusC-q: Inserting TextC-r: Repeat IsearchC-s: Basic IsearchC-S-backspace: Killing by LinesC-S-Mouse-3 (FFAP): FFAPC-SPC: Setting MarkC-t: TransposeC-u: ArgumentsC-u C-@: Mark RingC-u C-c C-w (Fortran mode): Fortran ColumnsC-u C-SPC: Mark RingC-u C-x C-x: Momentary MarkC-u C-x u: UndoC-u M-;: Comment CommandsC-u TAB: Multi-line IndentC-v: ScrollingC-v (Calendar mode): Scroll CalendarC-w: Other Kill CommandsC-x #: Emacs ServerC-x $: Selective DisplayC-x (: Basic Keyboard MacroC-x ): Basic Keyboard MacroC-x +: Change WindowC-x -: Change WindowC-x .: Fill PrefixC-x 0: Change WindowC-x 1: Change WindowC-x 2: Split WindowC-x 3: Split WindowC-x 4: Pop Up WindowC-x 4 .: Find TagC-x 4 0: Change WindowC-x 4 a: Change LogC-x 4 b: Select BufferC-x 4 b (Iswitchb mode): IswitchbC-x 4 c: Indirect BuffersC-x 4 C-o (Iswitchb mode): IswitchbC-x 4 d: Dired EnterC-x 4 f: VisitingC-x 4 f (FFAP): FFAPC-x 4 m: Sending MailC-x 5: Creating FramesC-x 5 .: Find TagC-x 5 0: Frame CommandsC-x 5 1: Frame CommandsC-x 5 2: Creating FramesC-x 5 b: Select BufferC-x 5 b (Iswitchb mode): IswitchbC-x 5 d: Dired EnterC-x 5 f: VisitingC-x 5 f (FFAP): FFAPC-x 5 m: Sending MailC-x 5 o: Frame CommandsC-x 5 r: Creating FramesC-x 6 1: Two-ColumnC-x 6 2: Two-ColumnC-x 6 b: Two-ColumnC-x 6 d: Two-ColumnC-x 6 RET: Two-ColumnC-x 6 s: Two-ColumnC-x 8: Single-Byte Character SupportC-x ;: Options for CommentsC-x <: Horizontal ScrollingC-x <LEFT>: Select BufferC-x <RET> F: Specify CodingC-x <RIGHT>: Select BufferC-x =: Position InfoC-x >: Horizontal ScrollingC-x [: PagesC-x [ (Calendar mode): Calendar Unit MotionC-x ]: PagesC-x ] (Calendar mode): Calendar Unit MotionC-x ^: Change WindowC-x `: Compilation ModeC-x a g: Defining AbbrevsC-x a i g: Defining AbbrevsC-x a i l: Defining AbbrevsC-x a l: Defining AbbrevsC-x b: Select BufferC-x b (Iswitchb mode): IswitchbC-x C-<SPC>: Global Mark RingC-x C-a (GUD): Commands of GUDC-x C-a C-j (GUD): Commands of GUDC-x C-b: List BuffersC-x C-c: ExitingC-x C-d: DirectoriesC-x C-e: Lisp EvalC-x C-f: VisitingC-x C-f (FFAP): FFAPC-x C-k b: Save Keyboard MacroC-x C-k C-a: Keyboard Macro CounterC-x C-k C-c: Keyboard Macro CounterC-x C-k C-d: Keyboard Macro RingC-x C-k C-e: Edit Keyboard MacroC-x C-k C-f: Keyboard Macro CounterC-x C-k C-i: Keyboard Macro CounterC-x C-k C-k: Keyboard Macro RingC-x C-k C-l: Keyboard Macro RingC-x C-k C-n: Keyboard Macro RingC-x C-k C-p: Keyboard Macro RingC-x C-k C-t: Keyboard Macro RingC-x C-k C-v: Keyboard Macro RingC-x C-k e: Edit Keyboard MacroC-x C-k l: Edit Keyboard MacroC-x C-k n: Save Keyboard MacroC-x C-k r: Basic Keyboard MacroC-x C-k RET: Edit Keyboard MacroC-x C-k SPC: Keyboard Macro Step-EditC-x C-l: CaseC-x C-n: Moving PointC-x C-o: Blank LinesC-x C-p: PagesC-x C-q: Misc BufferC-x C-q (Version Control): Basic VC EditingC-x C-r: 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CodingC-x RET r: Specify CodingC-x RET t: Specify CodingC-x RET X: Specify CodingC-x RET x: Specify CodingC-x s: Save CommandsC-x SPC: Commands of GUDC-x TAB: Indentation CommandsC-x TAB (Enriched mode): Format IndentationC-x u: UndoC-x v =: Old VersionsC-x v a: Change Logs and VCC-x v b: Local Version ControlC-x v c: VC UndoC-x v d: VC Dired ModeC-x v g: Old VersionsC-x v h: Version HeadersC-x v i: RegisteringC-x v l: VC StatusC-x v m: MergingC-x v r: Making SnapshotsC-x v s: Making SnapshotsC-x v u: VC UndoC-x v v: Basic VC EditingC-x v ~: Old VersionsC-x w b: Highlight InteractivelyC-x w h: Highlight InteractivelyC-x w i: Highlight InteractivelyC-x w l: Highlight InteractivelyC-x w r: Highlight InteractivelyC-x z: RepeatingC-x }: Change WindowC-y: Kill RingC-z: ExitingC-z (X windows): Frame Commandsd (Calendar mode): Displaying the DiaryD (Dired): Operating on Filesd (Dired): Dired DeletionD (GDB breakpoints buffer): Breakpoints Bufferd (Rmail): Rmail DeletionDEL: DeletionDEL (and 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mode): Special Diary Entriesi d (Calendar mode): Adding to Diaryi m (Calendar mode): Adding to Diaryi w (Calendar mode): Adding to Diaryi y (Calendar mode): Adding to DiaryINSERT: Minor Modesj (Rmail): Rmail Motionk (Dired): Dired Updatingk (Rmail): Rmail Labelsl (Dired): Dired UpdatingL (Dired): Operating on Filesl (Gnus Group mode): Summary of GnusL (Gnus Group mode): Summary of Gnusl (Rmail): Rmail Make SummaryLEFT: Moving Pointm (Calendar mode): Displaying the DiaryM (Calendar mode): Lunar PhasesM (Dired): Operating on Filesm (Dired): Marks vs Flagsm (Rmail): Rmail ReplyM-!: Single ShellM-$: SpellingM-$ (Dired): Hiding SubdirectoriesM-%: Query ReplaceM-': Expanding AbbrevsM-*: Find TagM-,: Tags SearchM--: ArgumentsM-- M-c: Fixing CaseM-- M-l: Fixing CaseM-- M-u: Fixing CaseM-.: Find TagM-/: Dynamic AbbrevsM-1: ArgumentsM-:: Lisp EvalM-;: Comment CommandsM-<: Moving PointM-< (Calendar mode): Move to Beginning or EndM-=: Position InfoM-= (Calendar mode): Counting DaysM-= (Dired): Comparison in DiredM->: Moving PointM-> (Calendar mode): Move to Beginning or EndM-? (Nroff mode): Nroff ModeM-? (Shell mode): Shell ModeM-@: WordsM-\: DeletionM-^: Indentation CommandsM-^ (Fortran mode): ForIndent CommandsM-`: Menu BarM-a: SentencesM-a (C mode): Motion in CM-a (Calendar mode): Move to Beginning or EndM-b: WordsM-c: CaseM-d: WordsM-DEL: WordsM-DEL (Dired): Marks vs FlagsM-Drag-Mouse-1: Secondary SelectionM-e: SentencesM-e (C mode): Motion in CM-e (Calendar mode): Move to Beginning or EndM-f: WordsM-g (Dired): Dired NavigationM-g M-n: Compilation ModeM-g n: Compilation ModeM-h: ParagraphsM-i: Tab StopsM-j: Multi-Line CommentsM-j b (Enriched mode): Format JustificationM-j c (Enriched mode): Format JustificationM-j l (Enriched mode): Format JustificationM-j r (Enriched mode): Format JustificationM-j u (Enriched mode): Format JustificationM-k: SentencesM-l: CaseM-m: Indentation CommandsM-m (Rmail): Rmail ReplyM-Mouse-1: Secondary SelectionM-Mouse-2: Secondary SelectionM-Mouse-3: Secondary SelectionM-n (minibuffer history): Minibuffer HistoryM-n (Nroff mode): Nroff ModeM-n (Rmail): Rmail MotionM-n (Shell mode): Shell RingM-o b (Enriched mode): Format FacesM-o d (Enriched mode): Format FacesM-o i (Enriched mode): Format FacesM-o l (Enriched mode): Format FacesM-o o (Enriched mode): Format FacesM-o u (Enriched mode): Format FacesM-p (minibuffer history): Minibuffer HistoryM-p (Nroff mode): Nroff ModeM-p (Rmail): Rmail MotionM-p (Shell mode): Shell RingM-q: Fill CommandsM-q (C mode): Other C CommandsM-q (Fortran mode): ForIndent CommandsM-r: Moving PointM-r (minibuffer history): Minibuffer HistoryM-r (Shell mode): Shell RingM-S (Enriched mode): Format JustificationM-s (Gnus Summary mode): Summary of GnusM-s (minibuffer history): Minibuffer HistoryM-s (Rmail): Rmail MotionM-s (Shell mode): Shell RingM-s (Text mode): Fill CommandsM-SPC: DeletionM-t: TransposeM-TAB: Symbol CompletionM-TAB (customization buffer): Changing a VariableM-TAB (Mail mode): Header EditingM-TAB (Picture mode): Tabs in PictureM-TAB (Text mode): Text ModeM-u: CaseM-v: ScrollingM-v (Calendar mode): Scroll CalendarM-w: Kill RingM-x: M-xM-y: Earlier KillsM-z: Other Kill CommandsM-{: ParagraphsM-{ (Calendar mode): Calendar Unit MotionM-{ (Dired): Marks vs FlagsM-|: Single ShellM-}: ParagraphsM-} (Calendar mode): Calendar Unit MotionM-} (Dired): Marks vs FlagsM-~: Save CommandsMouse-1: Mouse CommandsMouse-1 (mode line): Mode Line MouseMouse-1 (selection): Mouse ReferencesMouse-2: Mouse CommandsMouse-2 (mode line): Mode Line MouseMouse-2 (selection): Mouse ReferencesMouse-3: Mouse CommandsMouse-3 (mode line): Mode Line Mousen (Gnus): Summary of Gnusn (Rmail): Rmail MotionNEXT: Scrollingo (Calendar mode): Specified DatesO (Dired): Operating on Fileso (Dired): Dired Visitingo (Occur mode): Other Repeating Searcho (Rmail): Rmail Outputp (Calendar mode): To Other CalendarP (Dired): Operating on Filesp (Gnus): Summary of Gnusp (Rmail): Rmail Motionp d (Calendar mode): General CalendarPAGEDOWN: ScrollingPAGEUP: ScrollingPRIOR: Scrollingq (Calendar mode): General CalendarQ (Dired): Operating on Filesq (Gnus Group mode): Summary of Gnusq (Rmail summary): Rmail Summary EditQ (Rmail summary): Rmail Summary Editq (Rmail): Rmail BasicsR (Dired): Operating on Filesr (Rmail): Rmail ReplyRET: Inserting TextRET (Dired): Dired VisitingRET (GDB breakpoints buffer): Breakpoints BufferRET (GDB speedbar): Watch ExpressionsRET (Occur mode): Other Repeating SearchRET (Shell mode): Shell ModeRIGHT: Moving Points (Calendar mode): Displaying the DiaryS (Calendar mode): Sunrise/Sunsets (Dired): Dired UpdatingS (Dired): Operating on Filess (Gnus Summary mode): Summary of Gnuss (Rmail): Rmail BasicsS-<TAB> (Help mode): Help ModeS-Mouse-1: Frame ParametersS-Mouse-2: HideshowS-Mouse-3 (FFAP): FFAPS-TAB (customization buffer): Changing a VariableSPC: Completion CommandsSPC (Calendar mode): General CalendarSPC (Dired): Dired NavigationSPC (GDB breakpoints buffer): Breakpoints BufferSPC (Gnus): Summary of GnusSPC (Rmail): Rmail Scrollingt (Calendar mode): LaTeX CalendarT (Dired): Operating on Filest (Dired): Marks vs Flagst (Rmail): Rmail DisplayTAB: IndentationTAB (and major modes): Major ModesTAB (completion): Completion ExampleTAB (customization buffer): Changing a VariableTAB (GUD): Commands of GUDTAB (programming modes): Basic IndentTAB (Shell mode): Shell ModeTAB (Text mode): Text Modeu (Calendar mode): Holidaysu (Dired deletion): Dired DeletionU (Dired): Marks vs Flagsu (Dired): Marks vs Flagsu (Gnus Group mode): Summary of Gnusu (Rmail): Rmail DeletionUP: Moving Pointv (Dired): Dired Visitingw (Dired): Misc Dired Featuresw (Rmail): Rmail Outputx (Calendar mode): HolidaysX (Dired): Shell Commands in Diredx (Dired): Dired Deletionx (Rmail): Rmail DeletionZ (Dired): Operating on Files~ (Dired): Flagging Many Files+linenum: Action Arguments--background-color: Colors--basic-display: Misc X--batch: Initial Options--border-color: Colors--border-width: Borders X--color: Colors--cursor-color: Colors--debug-init: Initial Options--directory: Action Arguments--display: Initial Options--eval: Action Arguments--execute: Action Arguments--file: Action Arguments--find-file: Action Arguments--font: Font X--foreground-color: Colors--fullheight: Window Size X--fullscreen: Window Size X--fullwidth: Window Size X--funcall: Action Arguments--geometry: Window Size X--help: Action Arguments--horizontal-scroll-bars: Misc X--iconic: Icons X--insert: Action Arguments--internal-border: Borders X--kill: Action Arguments--line-spacing: Misc X--load: Action Arguments--mouse-color: Colors--multibyte: Initial Options--name: Resources--no-bitmap-icon: Icons X--no-blinking-cursor: Misc X--no-desktop: Initial Options--no-init-file: Initial Options--no-multibyte: Initial Options--no-site-file: Initial Options--no-splash: Initial Options--no-unibyte: Initial Options--no-window-system: Initial Options--quick: Initial Options--reverse-video: Colors--script: Initial Options--terminal: Initial Options--title: Title X--unibyte: Initial Options--user: Initial Options--version: Action Arguments--vertical-scroll-bars: Misc X--visit: Action Arguments--xrm: Resources-bd: Colors-bg: Colors-bw: Borders X-cr: Colors-D: Misc X-d: Initial Options-f: Action Arguments-fg: Colors-fh: Window Size X-fn: Font X-fs: Window Size X-fw: Window Size X-g: Window Size X-hb: Misc X-ib: Borders X-L: Action Arguments-l: Action Arguments-lsp: Misc X-ms: Colors-nbc: Misc X-nbi: Icons X-nw: Initial Options-Q: Initial Options-q: Initial Options-r: Colors-rv: Colors-T: Title X-t: Initial Options-u: Initial Options-vb: Misc X2C-associate-buffer: Two-Column2C-dissociate: Two-Column2C-merge: Two-Column2C-newline: Two-Column2C-split: Two-Column2C-two-columns: Two-Column5x5: Amusementsabbrev-mode: Abbrev Conceptsabbrev-prefix-mark: Expanding Abbrevsabort-recursive-edit: Quittingadd-change-log-entry-other-window: Change Logadd-global-abbrev: Defining Abbrevsadd-mode-abbrev: Defining Abbrevsadd-name-to-file: Misc File Opsadd-untranslated-filesystem: Text and Binaryamerican-calendar: Date Formatsappend-next-kill: Appending Killsappend-to-buffer: Accumulating Textappend-to-file: Accumulating Textappend-to-register: RegTextapply-macro-to-region-lines: Basic Keyboard Macroappt-activate: Appointmentsappt-add: Appointmentsappt-delete: Appointmentsapropos: Aproposapropos-command: Aproposapropos-documentation: Aproposapropos-value: Aproposapropos-variable: Aproposask-user-about-lock: Interlockingauto-compression-mode: Compressed Filesauto-fill-mode: Auto Fillauto-lower-mode: Frame Parametersauto-raise-mode: Frame Parametersauto-revert-mode: Revertingauto-revert-tail-mode: Revertingauto-save-mode: Auto Save Controlback-to-indentation: Indentation Commandsbackward-char: Moving Pointbackward-kill-sentence: Sentencesbackward-kill-word: Wordsbackward-list: Moving by Parensbackward-page: Pagesbackward-paragraph: Paragraphsbackward-sentence: Sentencesbackward-sexp: Expressionsbackward-text-line: Nroff Modebackward-up-list: Moving by Parensbackward-word: Wordsbalance-windows: Change Windowbashdb: Starting GUDbeginning-of-buffer: Moving Pointbeginning-of-defun: Moving by Defunsbinary-overwrite-mode: Minor Modesblackbox: Amusementsblink-cursor-mode: Cursor Displaybookmark-delete: Bookmarksbookmark-insert: Bookmarksbookmark-insert-location: Bookmarksbookmark-jump: Bookmarksbookmark-load: Bookmarksbookmark-save: Bookmarksbookmark-set: Bookmarksbookmark-write: Bookmarksbrowse-url: Browse-URLbrowse-url: Help Modebrowse-url-at-mouse: Browse-URLbrowse-url-at-point: Browse-URLbs-show: Buffer Menusbuffer-menu: Several Buffersbuffer-menu-other-window: Several Buffersc-backslash-region: Other C Commandsc-backward-conditional: Motion in Cc-backward-into-nomenclature: Motion in Cc-beginning-of-defun: Motion in Cc-beginning-of-statement: Motion in Cc-context-line-break: Other C Commandsc-electric-backspace: Program Modesc-end-of-defun: Motion in Cc-end-of-statement: Motion in Cc-fill-paragraph: Other C Commandsc-forward-conditional: Motion in Cc-forward-into-nomenclature: Motion in Cc-hungry-backspace: Hungry Deletec-hungry-delete-forward: Hungry Deletec-indent-command: C Indentc-indent-command: Basic Indentc-indent-defun: C Indentc-indent-exp: C Indentc-macro-expand: Other C Commandsc-mark-function: Moving by Defunsc-set-style: Custom C Indentc-show-syntactic-information: Other C Commandsc-subword-mode: Other C Commandsc-toggle-auto-newline: Electric Cc-toggle-electric-state: Electric Cc-toggle-hungry-state: Hungry Deletec-up-conditional: Motion in Ccalendar: Calendar/Diarycalendar-backward-day: Calendar Unit Motioncalendar-backward-month: Calendar Unit Motioncalendar-backward-week: Calendar Unit Motioncalendar-beginning-of-month: Move to Beginning or Endcalendar-beginning-of-week: Move to Beginning or Endcalendar-beginning-of-year: Move to Beginning or Endcalendar-count-days-region: Counting Dayscalendar-cursor-holidays: Holidayscalendar-end-of-month: Move to Beginning or Endcalendar-end-of-week: Move to Beginning or Endcalendar-end-of-year: Move to Beginning or Endcalendar-forward-day: Calendar Unit Motioncalendar-forward-month: Calendar Unit Motioncalendar-forward-week: Calendar Unit Motioncalendar-forward-year: Calendar Unit Motioncalendar-goto-astro-day-number: From Other Calendarcalendar-goto-chinese-date: From Other Calendarcalendar-goto-coptic-date: From Other Calendarcalendar-goto-date: Specified Datescalendar-goto-day-of-year: Specified Datescalendar-goto-ethiopic-date: From Other Calendarcalendar-goto-french-date: From Other Calendarcalendar-goto-hebrew-date: From Other Calendarcalendar-goto-islamic-date: From Other Calendarcalendar-goto-iso-date: From Other Calendarcalendar-goto-iso-week: From Other Calendarcalendar-goto-iso-week: Specified Datescalendar-goto-julian-date: From Other Calendarcalendar-goto-mayan-long-count-date: Mayan Calendarcalendar-goto-persian-date: From Other Calendarcalendar-goto-today: Specified Datescalendar-next-calendar-round-date: Mayan Calendarcalendar-next-haab-date: Mayan Calendarcalendar-next-tzolkin-date: Mayan Calendarcalendar-other-month: Specified Datescalendar-phases-of-moon: Lunar Phasescalendar-previous-haab-date: Mayan Calendarcalendar-previous-tzolkin-date: Mayan Calendarcalendar-print-astro-day-number: To Other Calendarcalendar-print-chinese-date: To Other Calendarcalendar-print-coptic-date: To Other Calendarcalendar-print-day-of-year: General Calendarcalendar-print-ethiopic-date: To Other Calendarcalendar-print-french-date: To Other Calendarcalendar-print-hebrew-date: To Other Calendarcalendar-print-islamic-date: To Other Calendarcalendar-print-iso-date: To Other Calendarcalendar-print-julian-date: To Other Calendarcalendar-print-mayan-date: To Other Calendarcalendar-print-persian-date: To Other Calendarcalendar-sunrise-sunset: Sunrise/Sunsetcalendar-unmark: Holidayscapitalize-word: Casecd: File Namescenter-line: Fill Commandschange-log-merge: Change Logchange-log-mode: Change Logchange-log-redate: Change Logcheck-parens: Parentheseschoose-completion: Completion Commandsclean-buffer-list: Kill Bufferclear-rectangle: Rectanglesclone-indirect-buffer: Indirect Buffersclone-indirect-buffer-other-window: Indirect Bufferscodepage-setup: MS-DOS and MULEcolumn-number-mode: Optional Mode Linecomint-bol-or-process-mark: Shell Modecomint-continue-subjob: Shell Modecomint-delchar-or-maybe-eof: Shell Modecomint-delete-output: Shell Modecomint-dynamic-complete: Shell Modecomint-dynamic-list-filename...: Shell Modecomint-dynamic-list-input-ring: Shell Ringcomint-get-next-from-history: Shell Ringcomint-input-previous-argument: Shell Ringcomint-insert-input: Shell History Copyingcomint-interrupt-subjob: Shell Modecomint-kill-input: Shell Modecomint-magic-space: History Referencescomint-next-input: Shell Ringcomint-next-matching-input: Shell Ringcomint-next-prompt: Shell History Copyingcomint-previous-input: Shell Ringcomint-previous-matching-input: Shell Ringcomint-previous-prompt: Shell History Copyingcomint-quit-subjob: Shell Modecomint-run: Shell Modecomint-send-input: Shell Modecomint-show-maximum-output: Shell Modecomint-show-output: Shell Modecomint-stop-subjob: Shell Modecomint-strip-ctrl-m: Shell Modecomint-truncate-buffer: Shell Modecomint-write-output: Shell Modecomment-dwim: Comment Commandscomment-indent-new-line: Multi-Line Commentscomment-kill: Comment Commandscomment-region: Multi-Line Commentscomment-set-column: Options for Commentscompare-windows: Comparing Filescompilation-next-error: Compilation Modecompilation-next-file: Compilation Modecompilation-previous-error: Compilation Modecompilation-previous-file: Compilation Modecompile: Compilationcompile (MS-DOS): MS-DOS Processescompile-goto-error: Compilation Modecomplete-symbol: Symbol Completioncompose-mail: Sending Mailcompose-mail-other-frame: Sending Mailcompose-mail-other-window: Sending Mailcopy-file: Misc File Opscopy-rectangle-to-register: RegRectcopy-to-buffer: Accumulating Textcopy-to-register: RegTextcount-lines-page: Pagescount-lines-region: Position Infocount-text-lines: Nroff Modecpp-highlight-buffer: Other C Commandscreate-fontset-from-fontset-spec: Defining Fontsetscrisp-mode: Emulationcua-mode: CUA Bindingscustomize: Easy Customizationcustomize-apropos: Specific Customizationcustomize-browse: Browsing Customcustomize-changed: Specific Customizationcustomize-create-theme: Custom Themescustomize-customized: Specific Customizationcustomize-face: Specific Customizationcustomize-group: Specific Customizationcustomize-saved: Specific Customizationcustomize-variable: Specific Customizationcwarn-mode: Other C Commandsdabbrev-completion: Dynamic Abbrevsdabbrev-expand: Dynamic Abbrevsdbx: Starting GUDdebug_print: Checklistdecipher: Amusementsdefault-value: Localsdefine-abbrevs: Saving Abbrevsdefine-global-abbrev: Defining Abbrevsdefine-key: Local Keymapsdefine-mail-abbrev: Mail Aliasesdefine-mail-alias: Mail Aliasesdefine-mode-abbrev: Defining Abbrevsdelete-backward-char: Deletiondelete-blank-lines: Blank Linesdelete-char: Deletiondelete-file: Misc File Opsdelete-frame: Frame Commandsdelete-horizontal-space: Deletiondelete-indentation: Indentation Commandsdelete-matching-lines: Other Repeating Searchdelete-non-matching-lines: Other Repeating Searchdelete-other-frames: Frame Commandsdelete-other-windows: Change Windowdelete-rectangle: Rectanglesdelete-selection-mode: Graphical Killdelete-trailing-whitespace: Useless Whitespacedelete-whitespace-rectangle: Rectanglesdelete-window: Change Windowdescribe-bindings: Misc Helpdescribe-categories: Regexp Backslashdescribe-character-set: Charsetsdescribe-coding-system: Coding Systemsdescribe-copying: Help Filesdescribe-distribution: Help Filesdescribe-function: Name Helpdescribe-input-method: Select Input Methoddescribe-key: Key Helpdescribe-key-briefly: Key Helpdescribe-language-environment: Language Environmentsdescribe-mode: Misc Helpdescribe-no-warranty: Help Filesdescribe-project: Help Filesdescribe-syntax: Syntaxdescribe-text-properties: Editing Format Infodesktop-change-dir: Saving Emacs Sessionsdesktop-clear: Saving Emacs Sessionsdesktop-revert: Saving Emacs Sessionsdesktop-save: Saving Emacs Sessionsdiary: Displaying the Diarydiary-anniversary: Special Diary Entriesdiary-block: Special Diary Entriesdiary-cyclic: Special Diary Entriesdiary-float: Special Diary Entriesdiary-mail-entries: Displaying the Diarydiff: Comparing Filesdiff-backup: Comparing Filesdiff-goto-source: Comparing Filesdiff-mode: Comparing Filesdigit-argument: Argumentsdired: Dired Enterdired-at-point: FFAPdired-backup-diff: Comparison in Direddired-change-marks: Marks vs Flagsdired-clean-directory: Flagging Many Filesdired-compare-directories: Misc Dired Featuresdired-copy-filename-as-kill: Misc Dired Featuresdired-create-directory: Operating on Filesdired-diff: Comparison in Direddired-display-file: Dired Visitingdired-do-byte-compile: Operating on Filesdired-do-chgrp: Operating on Filesdired-do-chmod: Operating on Filesdired-do-chown: Operating on Filesdired-do-compress: Operating on Filesdired-do-copy: Operating on Filesdired-do-copy-regexp: Transforming File Namesdired-do-delete: Operating on Filesdired-do-flagged-delete: Dired Deletiondired-do-hardlink: Operating on Filesdired-do-hardlink-regexp: Transforming File Namesdired-do-kill-lines: Dired Updatingdired-do-load: Operating on Filesdired-do-print: Operating on Filesdired-do-query-replace-regexp: Operating on Filesdired-do-redisplay: Dired Updatingdired-do-rename: Operating on Filesdired-do-rename-regexp: Transforming File Namesdired-do-search: Operating on Filesdired-do-shell-command: Shell Commands in Direddired-do-symlink: Operating on Filesdired-do-symlink-regexp: Transforming File Namesdired-do-touch: Operating on Filesdired-downcase: Transforming File Namesdired-find-file: Dired Visitingdired-find-file-other-window: Dired Visitingdired-flag-auto-save-files: Flagging Many Filesdired-flag-backup-files: Flagging Many Filesdired-flag-file-deletion: Dired Deletiondired-flag-files-regexp: Flagging Many Filesdired-flag-garbage-files: Flagging Many Filesdired-goto-file: Dired Navigationdired-hide-all: Hiding Subdirectoriesdired-hide-subdir: Hiding Subdirectoriesdired-mark: Marks vs Flagsdired-mark-directories: Marks vs Flagsdired-mark-executables: Marks vs Flagsdired-mark-files-containing-regexp: Marks vs Flagsdired-mark-files-regexp: Marks vs Flagsdired-mark-subdir-files: Marks vs Flagsdired-mark-symlinks: Marks vs Flagsdired-maybe-insert-subdir: Subdirectories in Direddired-mouse-find-file-other-window: Dired Visitingdired-next-dirline: Subdirectory Motiondired-next-marked-file: Marks vs Flagsdired-next-subdir: Subdirectory Motiondired-other-frame: Dired Enterdired-other-window: Dired Enterdired-prev-dirline: Subdirectory Motiondired-prev-marked-file: Marks vs Flagsdired-prev-subdir: Subdirectory Motiondired-sort-toggle-or-edit: Dired Updatingdired-toggle-marks: Marks vs Flagsdired-tree-down: Subdirectory Motiondired-tree-up: Subdirectory Motiondired-undo: Marks vs Flagsdired-unmark: Marks vs Flagsdired-unmark-all-files: Marks vs Flagsdired-unmark-all-marks: Marks vs Flagsdired-unmark-backward: Marks vs Flagsdired-up-directory: Dired Visitingdired-upcase: Transforming File Namesdired-view-file: Dired Visitingdirs: Directory Trackingdirtrack-mode: Directory Trackingdisable-command: Disablingdisable-theme: Custom Themesdisplay-local-help: Help Echodisplay-time: Optional Mode Linedissociated-press: Dissociated Pressdo-applescript: Mac Functionsdo-auto-save: Auto Save Controldoctex-mode: TeX Modedoctor: Total Frustrationdown-list: Moving by Parensdowncase-region: Casedowncase-word: Casedunnet: Amusementsedit-abbrevs: Editing Abbrevsedit-kbd-macro: Edit Keyboard Macroedit-picture: Pictureedit-tab-stops: Tab Stopsedit-tab-stops-note-changes: Tab Stopsedt-emulation-off: Emulationedt-emulation-on: Emulationeldoc-mode: Lisp Docelectric-nroff-mode: Nroff Modeemacs-lisp-mode: Lisp Evalemacs-version: Understanding Bug Reportingemerge-auto-advance-mode: Submodes of Emergeemerge-buffers: Overview of Emergeemerge-buffers-with-ancestor: Overview of Emergeemerge-files: Overview of Emergeemerge-files-with-ancestor: Overview of Emergeemerge-skip-prefers-mode: Submodes of Emergeenable-command: Disablingenable-flow-control: Unasked-for Searchenable-flow-control-on: Unasked-for Searchenable-local-eval: File Variablesenable-local-variables: File Variablesenable-theme: Custom Themesend-of-buffer: Moving Pointend-of-defun: Moving by Defunsenlarge-window: Change Windowenlarge-window-horizontally: Change Windowenriched-mode: Requesting Formatted Texteshell: Shelleuropean-calendar: Date Formatseval-current-buffer: Lisp Evaleval-defun: Lisp Evaleval-expression: Lisp Evaleval-last-sexp: Lisp Evaleval-region: Lisp Evalexchange-point-and-mark: Setting Markexecute-extended-command: M-xexit-calendar: General Calendarexit-recursive-edit: Recursive Editexpand-abbrev: Expanding Abbrevsexpand-mail-aliases: Mail Aliasesexpand-region-abbrevs: Expanding Abbrevsf90-beginning-of-block: Fortran Motionf90-end-of-block: Fortran Motionf90-mode: Fortranf90-next-block: Fortran Motionf90-next-statement: Fortran Motionf90-previous-block: Fortran Motionf90-previous-statement: Fortran Motionfacemenu-remove-all: Editing Format Infofacemenu-remove-face-props: Editing Format Infofacemenu-set-background: Format Colorsfacemenu-set-bold: Format Facesfacemenu-set-bold-italic: Format Facesfacemenu-set-default: Format Facesfacemenu-set-face: Format Facesfacemenu-set-foreground: Format Colorsfacemenu-set-italic: Format Facesfacemenu-set-underline: Format Facesff-find-related-file: Other C Commandsffap: FFAPffap-menu: FFAPffap-mode: FFAPffap-next: FFAPfile-cache-add-directory: File Name Cachefile-cache-minibuffer-complete: File Name Cachefile-name-shadow-mode: Minibuffer Filefilesets-add-buffer: Filesetsfilesets-init: Filesetsfilesets-remove-buffer: Filesetsfill-individual-paragraphs: Fill Prefixfill-nonuniform-paragraphs: Fill Prefixfill-paragraph: Fill Commandsfill-region: Fill Commandsfill-region-as-paragraph: Fill Commandsfind-alternate-file: Visitingfind-dired: Dired and Findfind-file: Visitingfind-file-at-point: FFAPfind-file-literally: Visitingfind-file-other-frame: Visitingfind-file-other-window: Visitingfind-file-read-only: Visitingfind-file-read-only-other-frame: Creating Framesfind-grep: Grep Searchingfind-grep-dired: Dired and Findfind-name-dired: Dired and Findfind-tag: Find Tagfind-tag-other-frame: Find Tagfind-tag-other-window: Find Tagfind-tag-regexp: Find Tagfinder-by-keyword: Library Keywordsflush-lines: Other Repeating Searchflyspell-mode: Spellingflyspell-prog-mode: Spellingfoldout-exit-fold: Foldoutfoldout-zoom-subtree: Foldoutfollow-mode: Follow Modefont-lock-add-keywords: Font Lockfont-lock-mode: Font Lockfont-lock-remove-keywords: Font Lockformat-find-file: Forcing Enriched Modefortran-beginning-of-block: Fortran Motionfortran-column-ruler: Fortran Columnsfortran-comment-region: Fortran Commentsfortran-end-of-block: Fortran Motionfortran-indent-comment: Fortran Commentsfortran-indent-subprogram: ForIndent Commandsfortran-join-line: ForIndent Commandsfortran-mode: Fortranfortran-next-statement: Fortran Motionfortran-previous-statement: Fortran Motionfortran-split-line: ForIndent Commandsfortran-strip-sequence-nos: Fortran Columnsfortran-window-create: Fortran Columnsfortran-window-create-momentarily: Fortran Columnsfortune-to-signature: Mail Amusementsforward-char: Moving Pointforward-list: Moving by Parensforward-page: Pagesforward-paragraph: Paragraphsforward-sentence: Sentencesforward-sexp: Expressionsforward-text-line: Nroff Modeforward-word: Wordsframe-configuration-to-register: RegConfigfringe-mode: Fringesgdb: Starting GUDgdb-delete-breakpoint: Breakpoints Buffergdb-edit-value: Watch Expressionsgdb-frames-select: Stack Buffergdb-goto-breakpoint: Breakpoints Buffergdb-many-windows: GDB User Interface Layoutgdb-mouse-set-clear-breakpoint: GDB Graphical Interfacegdb-mouse-toggle-breakpoint: GDB Graphical Interfacegdb-restore-windows: GDB User Interface Layoutgdb-threads-select: Other GDB User Interface Buffersgdb-toggle-breakpoint: Breakpoints Buffergdb-var-delete: Watch Expressionsgdba: GDB Graphical Interfacegetenv: Environmentglasses-mode: Glassesglobal-auto-revert-mode: Revertingglobal-cwarn-mode: Other C Commandsglobal-font-lock-mode: Font Lockglobal-hl-line-mode: Cursor Displayglobal-set-key: Rebindingglobal-unset-key: Rebindinggnus: Gnusgnus-group-exit: Summary of Gnusgnus-group-kill-group: Summary of Gnusgnus-group-list-all-groups: Summary of Gnusgnus-group-list-groups: Summary of Gnusgnus-group-next-group: Summary of Gnusgnus-group-next-unread-group: Summary of Gnusgnus-group-prev-group: Summary of Gnusgnus-group-prev-unread-group: Summary of Gnusgnus-group-read-group: Summary of Gnusgnus-group-unsubscribe-current-group: Summary of Gnusgnus-summary-isearch-article: Summary of Gnusgnus-summary-next-subject: Summary of Gnusgnus-summary-next-unread-article: Summary of Gnusgnus-summary-prev-page: Summary of Gnusgnus-summary-prev-subject: Summary of Gnusgnus-summary-prev-unread-article: Summary of Gnusgnus-summary-search-article-forward: Summary of Gnusgomoku: Amusementsgoto-address: Goto-addressgoto-char: Moving Pointgoto-line: Moving Pointgrep: Grep Searchinggrep (MS-DOS): MS-DOS Processesgrep-find: Grep Searchinggud-cont: Commands of GUDgud-def: GUD Customizationgud-down: Commands of GUDgud-finish: Commands of GUDgud-gdb-complete-command: Commands of GUDgud-jump: Commands of GUDgud-next: Commands of GUDgud-refresh: Commands of GUDgud-remove: Commands of GUDgud-run: Commands of GUDgud-step: Commands of GUDgud-stepi: Commands of GUDgud-tbreak: Commands of GUDgud-until: Commands of GUDgud-up: Commands of GUDgud-watch: Watch Expressionshandwrite: PostScripthanoi: Amusementshelp-command: Helphelp-for-help: Helphelp-next-ref: Help Modehelp-previous-ref: Help Modehelp-with-tutorial: Basichi-lock-find-patterns: Highlight Interactivelyhi-lock-mode: Highlight Interactivelyhi-lock-write-interactive-patterns: Highlight Interactivelyhide-body: Outline Visibilityhide-entry: Outline Visibilityhide-ifdef-mode: Other C Commandshide-leaves: Outline Visibilityhide-other: Outline Visibilityhide-sublevels: Outline Visibilityhide-subtree: Outline Visibilityhighlight-changes-mode: Highlight Changeshighlight-lines-matching-regexp: Highlight Interactivelyhighlight-regexp: Highlight Interactivelyhl-line-mode: Cursor Displayholidays: Holidayshow-many: Other Repeating Searchhs-hide-all: Hideshowhs-hide-block: Hideshowhs-hide-level: Hideshowhs-minor-mode: Hideshowhs-show-all: Hideshowhs-show-block: Hideshowhs-show-region: Hideshowicalendar-export-file, icalendar-export-region: Importing Diaryicalendar-import-buffer: Importing Diaryicalendar-import-file: Importing Diaryicomplete-mode: Completion Optionsiconify-or-deiconify-frame: Frame Commandsielm: Lisp Interactionimage-mode: File Conveniencesimage-toggle-display: File Conveniencesimenu: Imenuimenu-add-menubar-index: Imenuincrease-left-margin: Format Indentationincrement-register: RegNumbersindent-code-rigidly: Multi-line Indentindent-for-tab-command: Basic Indentindent-line-function: Basic Indentindent-pp-sexp: Multi-line Indentindent-region: Indentation Commandsindent-relative: Indentation Commandsindent-rigidly: Indentation Commandsinfo: Misc HelpInfo-goto-emacs-command-node: Misc HelpInfo-goto-emacs-key-command-node: Misc Helpinfo-lookup-file: Info Lookupinfo-lookup-symbol: Info Lookupinfo-lookup-symbol: Misc Helpinsert-abbrevs: Saving Abbrevsinsert-anniversary-diary-entry: Special Diary Entriesinsert-block-diary-entry: Special Diary Entriesinsert-cyclic-diary-entry: Special Diary Entriesinsert-diary-entry: Adding to Diaryinsert-file: Misc File Opsinsert-kbd-macro: Save Keyboard Macroinsert-monthly-diary-entry: Adding to Diaryinsert-register: RegTextinsert-weekly-diary-entry: Adding to Diaryinsert-yearly-diary-entry: Adding to Diaryinverse-add-global-abbrev: Defining Abbrevsinverse-add-mode-abbrev: Defining Abbrevsisearch-backward: Repeat Isearchisearch-backward-regexp: Regexp Searchisearch-forward: Basic Isearchisearch-forward-regexp: Regexp Searchisearch-toggle-input-method: Non-ASCII Isearchisearch-toggle-specified-input-method: Non-ASCII Isearchiso-gtex2iso: TeX Misciso-iso2gtex: TeX Misciso-iso2tex: TeX Misciso-tex2iso: TeX Miscispell: Spellingispell-buffer: Spellingispell-complete-word: Spellingispell-kill-ispell: Spellingispell-message: Mail Mode Miscispell-region: Spellingispell-word: Spellingiswitchb-mode: Iswitchbjdb: Starting GUDjump-to-register: RegPosjust-one-space: Deletionkbd-macro-query: Keyboard Macro Querykeep-lines: Other Repeating Searchkeyboard-escape-quit: Quittingkeyboard-quit: Quittingkill-all-abbrevs: Defining Abbrevskill-buffer: Kill Bufferkill-buffer-and-window: Change Windowkill-compilation: Compilationkill-line: Killing by Lineskill-local-variable: Localskill-rectangle: Rectangleskill-region: Other Kill Commandskill-ring-save: Kill Ringkill-sentence: Sentenceskill-sexp: Expressionskill-some-buffers: Kill Bufferkill-whole-line: Killing by Lineskill-word: Wordskmacro-add-counter: Keyboard Macro Counterkmacro-bind-to-key: Save Keyboard Macrokmacro-call-ring-2nd-repeat: Keyboard Macro Ringkmacro-cycle-ring-next: Keyboard Macro Ringkmacro-cycle-ring-previous: Keyboard Macro Ringkmacro-delete-ring-head: Keyboard Macro Ringkmacro-edit-lossage: Edit Keyboard Macrokmacro-edit-macro: Edit Keyboard Macrokmacro-end-and-call-macro: Basic Keyboard Macrokmacro-end-macro: Basic Keyboard Macrokmacro-end-or-call-macro-repeat: Keyboard Macro Ringkmacro-insert-counter: Keyboard Macro Counterkmacro-name-last-macro: Save Keyboard Macrokmacro-set-counter: Keyboard Macro Counterkmacro-set-format: Keyboard Macro Counterkmacro-start-macro: Basic Keyboard Macrokmacro-step-edit-macro: Keyboard Macro Step-Editkmacro-swap-ring: Keyboard Macro Ringkmacro-view-macro-repeat: Keyboard Macro Ringlatex-mode: TeX Modelife: Amusementsline-number-mode: Optional Mode Linelisp-complete-symbol: Symbol Completionlisp-eval-defun: External Lisplisp-interaction-mode: Lisp Interactionlisp-mode: External Lisplist-abbrevs: Editing Abbrevslist-bookmarks: Bookmarkslist-buffers: List Bufferslist-calendar-holidays: Holidayslist-charset-chars: Charsetslist-coding-systems: Coding Systemslist-colors-display: Colorslist-command-history: Repetitionlist-directory: Directorieslist-faces-display: Standard Faceslist-holidays: Holidayslist-input-methods: Select Input Methodlist-matching-lines: Other Repeating Searchlist-tags: List Tagslist-yahrzeit-dates: From Other Calendarlm: Amusementsload: Lisp Librariesload-file: Lisp Librariesload-library: Lisp Librariesload-theme: Custom Themeslocal-set-key: Rebindinglocal-unset-key: Rebindinglocate: Dired and Findlocate-with-filter: Dired and Findlog-edit-insert-changelog: Log Bufferlonglines-auto-wrap: Longlineslonglines-mode: Longlineslonglines-show-hard-newlines: Longlineslpr-buffer: Printinglpr-region: Printingmac-file-name-to-posix: Mac Functionsmac-get-file-creator: Mac Functionsmac-get-file-type: Mac Functionsmac-get-preference: Mac Functionsmac-set-file-creator: Mac Functionsmac-set-file-type: Mac Functionsmail-attach-file: Mail Mode Miscmail-bcc: Header Editingmail-cc: Header Editingmail-complete: Header Editingmail-fcc: Header Editingmail-fill-yanked-message: Citing Mailmail-interactive-insert-alias: Mail Aliasesmail-send: Mail Sendingmail-send-and-exit: Mail Sendingmail-signature: Mail Mode Miscmail-subject: Header Editingmail-text: Mail Mode Miscmail-to: Header Editingmail-yank-original: Citing Mailmail-yank-region: Citing Mailmake-frame-command: Creating Framesmake-frame-on-display: Multiple Displaysmake-indirect-buffer: Indirect Buffersmake-local-variable: Localsmake-symbolic-link: Misc File Opsmake-variable-buffer-local: LocalsMan-fontify-manpage: Man Pagemanual-entry: Man Pagemark-calendar-holidays: Holidaysmark-defun: Moving by Defunsmark-diary-entries: Displaying the Diarymark-page: Pagesmark-paragraph: Paragraphsmark-sexp: Expressionsmark-whole-buffer: Marking Objectsmark-word: Wordsmenu-bar-enable-clipboard: Clipboardminibuffer-complete: Completion Exampleminibuffer-complete-word: Completion Commandsmode, thumbs: File Conveniencesmode25: MS-DOS Displaymode4350: MS-DOS Displaymodify-face: Face Customizationmorse-region: Amusementsmouse-avoidance-mode: Mouse Avoidancemouse-buffer-menu: Buffer Menusmouse-choose-completion: Completion Commandsmouse-save-then-click: Mouse Commandsmouse-secondary-save-then-kill: Secondary Selectionmouse-set-point: Mouse Commandsmouse-set-region: Mouse Commandsmouse-set-secondary: Secondary Selectionmouse-start-secondary: Secondary Selectionmouse-wheel-mode: Wheeled Micemouse-yank-at-click: Mouse Commandsmouse-yank-secondary: Secondary Selectionmove-beginning-of-line: Moving Pointmove-end-of-line: Moving Pointmove-to-window-line: Moving Pointmpuz: Amusementsmsb-mode: Buffer Menusmsdos-set-mouse-buttons: MS-DOS Mousemulti-occur: Other Repeating Searchmulti-occur-by-filename-regexp: Other Repeating Searchnarrow-to-defun: Narrowingnarrow-to-page: Narrowingnarrow-to-region: Narrowingnegative-argument: Argumentsnewline: Inserting Textnewline-and-indent: Basic Indentnext-buffer: Select Buffernext-completion: Completion Commandsnext-error: Compilation Modenext-error-follow-minor-mode: Compilation Modenext-history-element: Minibuffer Historynext-line: Moving Pointnext-matching-history-element: Minibuffer Historynormal-erase-is-backspace-mode: DEL Does Not Deletenormal-erase-is-backspace-mode: Deletionnormal-mode: Choosing Modesnot-modified: Save Commandsnroff-mode: Nroff Modenumber-to-register: RegNumbersoccur: Other Repeating Searchopen-dribble-file: Checklistopen-line: Blank Linesopen-rectangle: Rectanglesopen-termscript: Checklistother-frame: Frame Commandsother-window: Other Windowoutline-backward-same-level: Outline Motionoutline-forward-same-level: Outline Motionoutline-minor-mode: Outline Modeoutline-mode: Outline Modeoutline-next-visible-heading: Outline Motionoutline-previous-visible-heading: Outline Motionoutline-up-heading: Outline Motionoverwrite-mode: Minor Modesparagraph-indent-minor-mode: Text Modeparagraph-indent-text-mode: Text Modepartial-completion-mode: Completion Optionspdb: Starting GUDperldb: Starting GUDphases-of-moon: Lunar Phasespicture-backward-clear-column: Basic Picturepicture-backward-column: Basic Picturepicture-clear-column: Basic Picturepicture-clear-line: Basic Picturepicture-clear-rectangle: Rectangles in Picturepicture-clear-rectangle-to-register: Rectangles in Picturepicture-forward-column: Basic Picturepicture-motion: Insert in Picturepicture-motion-reverse: Insert in Picturepicture-move-down: Basic Picturepicture-move-up: Basic Picturepicture-movement-down: Insert in Picturepicture-movement-left: Insert in Picturepicture-movement-ne: Insert in Picturepicture-movement-nw: Insert in Picturepicture-movement-right: Insert in Picturepicture-movement-se: Insert in Picturepicture-movement-sw: Insert in Picturepicture-movement-up: Insert in Picturepicture-newline: Basic Picturepicture-open-line: Basic Picturepicture-set-tab-stops: Tabs in Picturepicture-tab: Tabs in Picturepicture-tab-search: Tabs in Picturepicture-yank-rectangle: Rectangles in Picturepicture-yank-rectangle-from-register: Rectangles in Pictureplain-tex-mode: TeX Modepoint-to-register: RegPospong: Amusementspop-global-mark: Global Mark Ringpop-tag-mark: Find Tagposix-file-name-to-mac: Mac Functionspr-interface: Printing Packageprefer-coding-system: Recognize Codingprepend-to-buffer: Accumulating Textprepend-to-register: RegTextprevious-buffer: Select Bufferprevious-completion: Completion Commandsprevious-history-element: Minibuffer Historyprevious-line: Moving Pointprevious-matching-history-element: Minibuffer Historyprint-buffer: Printingprint-buffer (MS-DOS): MS-DOS Printingprint-region: Printingprint-region (MS-DOS): MS-DOS Printingps-print-buffer: PostScriptps-print-buffer (MS-DOS): MS-DOS Printingps-print-buffer-with-faces: PostScriptps-print-region: PostScriptps-print-region-with-faces: PostScriptps-spool-buffer: PostScriptps-spool-buffer (MS-DOS): MS-DOS Printingps-spool-buffer-with-faces: PostScriptps-spool-region: PostScriptps-spool-region-with-faces: PostScriptpwd: File Namesquail-set-keyboard-layout: Select Input Methodquail-show-key: Select Input Methodquery-replace: Query Replacequery-replace-regexp: Query Replacequietly-read-abbrev-file: Saving Abbrevsquoted-insert: Inserting Textre-search-backward: Regexp Searchre-search-forward: Regexp Searchread-abbrev-file: Saving Abbrevsrecenter: Scrollingrecentf-edit-list: File Conveniencesrecentf-mode: File Conveniencesrecentf-save-list: File Conveniencesrecode-file-name: Specify Codingrecode-region: Specify Codingrecompile: Compilationrecover-file: Recoverrecover-session: Recoverredraw-calendar: General Calendarremove-untranslated-filesystem: Text and Binaryrename-buffer: Misc Bufferrename-file: Misc File Opsrename-uniquely: Misc Bufferrepeat: Repeatingrepeat-complex-command: Repetitionreplace-regexp: Regexp Replacereplace-string: Unconditional Replacereport-emacs-bug: Checklistreposition-window: Scrollingreveal-mode: Outline Visibilityrevert-buffer: Revertingrevert-buffer (Dired): Dired Updatingrevert-buffer-with-coding-system: Specify Codingrmail: Rmailrmail-add-label: Rmail Labelsrmail-beginning-of-message: Rmail Scrollingrmail-bury: Rmail Basicsrmail-continue: Rmail Replyrmail-delete-backward: Rmail Deletionrmail-delete-forward: Rmail Deletionrmail-edit-current-message: Rmail Editingrmail-expunge: Rmail Deletionrmail-expunge-and-save: Rmail Basicsrmail-first-message: Rmail Motionrmail-forward: Rmail Replyrmail-get-new-mail: Rmail Filesrmail-input: Rmail Filesrmail-kill-label: Rmail Labelsrmail-last-message: Rmail Motionrmail-mail: Rmail Replyrmail-mode: Rmailrmail-next-labeled-message: Rmail Labelsrmail-next-message: Rmail Motionrmail-next-undeleted-message: Rmail Motionrmail-output: Rmail Outputrmail-output-body-to-file: Rmail Outputrmail-output-to-rmail-file: Rmail Outputrmail-previous-labeled-message: Rmail Labelsrmail-previous-message: Rmail Motionrmail-previous-undeleted-message: Rmail Motionrmail-quit: Rmail Basicsrmail-redecode-body: Rmail Codingrmail-reply: Rmail Replyrmail-resend: Rmail Replyrmail-retry-failure: Rmail Replyrmail-search: Rmail Motionrmail-show-message: Rmail Motionrmail-summary: Rmail Make Summaryrmail-summary-by-labels: Rmail Make Summaryrmail-summary-by-recipients: Rmail Make Summaryrmail-summary-by-regexp: Rmail Make Summaryrmail-summary-by-topic: Rmail Make Summaryrmail-summary-quit: Rmail Summary Editrmail-summary-wipe: Rmail Summary Editrmail-toggle-header: Rmail Displayrmail-undelete-previous-message: Rmail Deletionrot13-other-window: Rmail Rot13run-lisp: External Lispsafe-local-eval-forms: File Variablessave-buffer: Save Commandssave-buffers-kill-emacs: Exitingsave-some-buffers: Save Commandsscroll-all-mode: Emulationscroll-bar-mode: Scroll Barsscroll-calendar-left: Scroll Calendarscroll-calendar-left-three-months: Scroll Calendarscroll-calendar-right: Scroll Calendarscroll-calendar-right-three-months: Scroll Calendarscroll-down: Scrollingscroll-left: Horizontal Scrollingscroll-other-window: Other Windowscroll-right: Horizontal Scrollingscroll-up: Scrollingsdb: Starting GUDsearch-backward: Nonincremental Searchsearch-forward: Nonincremental Searchselect-frame-by-name: Non-Window Terminalsself-insert: Inserting Textsend-invisible: Shell Modeserver-edit: Emacs Serverset-background-color: Frame Parametersset-border-color: Frame Parametersset-buffer-file-coding-system: Specify Codingset-buffer-process-coding-system: Specify Codingset-cursor-color: Frame Parametersset-face-background: Facesset-face-foreground: Facesset-file-name-coding-system: Specify Codingset-fill-column: Fill Commandsset-fill-prefix: Fill Prefixset-foreground-color: Frame Parametersset-frame-font: Frame Parametersset-frame-name: Non-Window Terminalsset-fringe-style: Fringesset-goal-column: Moving Pointset-input-method: Select Input Methodset-justification-center: Format Justificationset-justification-full: Format Justificationset-justification-left: Format Justificationset-justification-none: Format Justificationset-justification-right: Format Justificationset-keyboard-coding-system: Specify Codingset-language-environment: Language Environmentsset-left-margin: Format Indentationset-locale-environment: Language Environmentsset-mark-command: Setting Markset-mouse-color: Frame Parametersset-next-selection-coding-system: Specify Codingset-right-margin: Format Indentationset-rmail-inbox-list: Rmail Filesset-selection-coding-system: Specify Codingset-selective-display: Selective Displayset-terminal-coding-system: Specify Codingset-variable: Examiningset-visited-file-name: Save Commandssetenv: Environmentsetq-default: Localssgml-attributes: HTML Modesgml-close-tag: HTML Modesgml-delete-tag: HTML Modesgml-name-8bit-mode: HTML Modesgml-name-char: HTML Modesgml-skip-tag-backward: HTML Modesgml-skip-tag-forward: HTML Modesgml-tag: HTML Modesgml-tag-help: HTML Modesgml-tags-invisible: HTML Modesgml-validate: HTML Modeshell: Interactive Shellshell-backward-command: Shell Modeshell-command: Single Shellshell-command-on-region: Single Shellshell-forward-command: Shell Modeshell-pushd-dextract: Shell Optionsshell-pushd-dunique: Shell Optionsshell-pushd-tohome: Shell Optionsshow-all: Outline Visibilityshow-all-diary-entries: Displaying the Diaryshow-branches: Outline Visibilityshow-children: Outline Visibilityshow-entry: Outline Visibilityshow-paren-mode: Matchingshow-subtree: Outline Visibilityshrink-window-if-larger-than-buffer: Change Windowsize-indication-mode: Optional Mode Lineslitex-mode: TeX Modesmerge-mode: Comparing Filessnake: Amusementssolitaire: Amusementssort-columns: Sortingsort-fields: Sortingsort-lines: Sortingsort-numeric-fields: Sortingsort-pages: Sortingsort-paragraphs: Sortingsplit-line: Indentation Commandssplit-window-horizontally: Split Windowsplit-window-vertically: Split Windowspook: Mail Amusementsstandard-display-8bit: Single-Byte Character Supportstring-insert-rectangle: Rectanglesstring-rectangle: Rectanglesstudlify-region: Amusementssubstitute-in-file-name: File Namessubstitute-key-definition: Init Examplessunrise-sunset: Sunrise/Sunsetsuspend-emacs: Exitingswitch-to-buffer: Select Bufferswitch-to-buffer-other-frame: Select Bufferswitch-to-buffer-other-window: Select Bufferswitch-to-completions: Completion Commandstab-to-tab-stop: Tab Stopstabify: Just Spacestable-backward-cell: Cell Commandstable-capture: Table Conversiontable-delete-row: Row Commandstable-fixed-width-mode: Fixed Width Modetable-forward-cell: Cell Commandstable-generate-source: Table Misctable-heighten-cell: Cell Commandstable-insert: Table Creationtable-insert-column: Column Commandstable-insert-row: Row Commandstable-insert-sequence: Table Misctable-justify: Cell Justificationtable-narrow-cell: Cell Commandstable-query-dimension: Measuring Tablestable-recognize: Table Recognitiontable-recognize-cell: Table Recognitiontable-recognize-region: Table Recognitiontable-recognize-table: Table Recognitiontable-release: Table Conversiontable-shorten-cell: Cell Commandstable-span-cell: Cell Commandstable-split-cell: Cell Commandstable-split-cell-horizontally: Cell Commandstable-split-cell-vertically: Cell Commandstable-unrecognize: Table Recognitiontable-unrecognize-cell: Table Recognitiontable-unrecognize-region: Table Recognitiontable-unrecognize-table: Table Recognitiontable-widen-cell: Cell Commandstags-apropos: List Tagstags-loop-continue: Tags Searchtags-query-replace: Tags Searchtags-search: Tags Searchterm: Terminal emulatorterm-char-mode: Term Modeterm-line-mode: Term Modeterm-pager-toggle: Paging in Termtetris: Amusementstex-bibtex-file: TeX Printtex-buffer: TeX Printtex-close-latex-block: LaTeX Editingtex-compile: TeX Printtex-file: TeX Printtex-insert-braces: TeX Editingtex-insert-quote: TeX Editingtex-kill-job: TeX Printtex-latex-block: LaTeX Editingtex-mode: TeX Modetex-print: TeX Printtex-recenter-output-buffer: TeX Printtex-region: TeX Printtex-show-print-queue: TeX Printtex-terminate-paragraph: TeX Editingtex-validate-region: TeX Editingtex-view: TeX Printtext-mode: Text Modethumbs-mode: File Conveniencestime-stamp: Time Stampstimeclock-change: Time Intervalstimeclock-in: Time Intervalstimeclock-modeline-display: Time Intervalstimeclock-out: Time Intervalstimeclock-reread-log: Time Intervalstimeclock-when-to-leave: Time Intervalstimeclock-workday-remaining: Time Intervalstmm-menubar: Menu Bartoggle-debug-on-error: Checklisttoggle-enable-multibyte-characters: Enabling Multibytetoggle-gdb-all-registers: Other GDB User Interface Bufferstoggle-input-method: Select Input Methodtoggle-read-only: Misc Buffertoggle-scroll-bar: Scroll Barstoggle-truncate-lines: Display Customtooltip-mode: Tooltipstop-level: Quittingtpu-edt-on: Emulationtransient-mark-mode: Transient Marktranspose-chars: Transposetranspose-lines: Transposetranspose-sexps: Expressionstranspose-words: Transposetty-suppress-bold-inverse-default-colors: Display Customturn-on-font-lock: Font Lockundigestify-rmail-message: Rmail Digestundo: Undoundo-only: Undounexpand-abbrev: Expanding Abbrevsunforward-rmail-message: Rmail Replyunhighlight-regexp: Highlight Interactivelyunify-8859-on-decoding-mode: Recognize Codinguniversal-argument: Argumentsuniversal-coding-system-argument: Specify Codingunmorse-region: Amusementsunrmail: Out of Rmailuntabify: Just Spacesup-list: TeX Editingupcase-region: Caseupcase-word: Casevc-annotate: Old Versionsvc-cancel-version: VC Undovc-create-snapshot: Making Snapshotsvc-diff: Old Versionsvc-directory: VC Dired Modevc-dired-mark-locked: VC Dired Commandsvc-dired-toggle-terse-mode: VC Dired Commandsvc-insert-headers: Version Headersvc-merge: Mergingvc-next-action: Basic VC Editingvc-print-log: VC Statusvc-register: Registeringvc-rename-file: Renaming and VCvc-retrieve-snapshot: Making Snapshotsvc-revert-buffer: VC Undovc-switch-backend: Local Version Controlvc-toggle-read-only: Basic VC Editingvc-update-change-log: Change Logs and VCvc-version-other-window: Old Versionsvi-mode: Emulationview-buffer: Misc Bufferview-diary-entries: Displaying the Diaryview-echo-area-messages: Misc Helpview-emacs-FAQ: Help Filesview-emacs-news: Help Filesview-emacs-problems: Help Filesview-emacs-todo: Help Filesview-file: Misc File Opsview-hello-file: International Charsview-lossage: Misc Helpview-register: Registersvip-mode: Emulationviper-mode: Emulationvisit-tags-table: Select Tags Tablewdired-change-to-wdired-mode: Wdiredwdired-finish-edit: Wdiredwhat-cursor-position: Position Infowhat-line: Position Infowhat-page: Position Infowhere-is: Key Helpwhich-function-mode: Which Functionwiden: Narrowingwidget-backward: Changing a Variablewidget-complete: Changing a Variablewidget-forward: Changing a Variablewindmove-default-keybindings: Window Conveniencewindmove-right: Window Conveniencewindow-configuration-to-register: RegConfigwinner-mode: Window Conveniencewoman: Man Pagewoman-find-file: Man Pageword-search-backward: Word Searchword-search-forward: Word Searchwordstar-mode: Emulationwrite-abbrev-file: Saving Abbrevswrite-file: Save Commandswrite-region: Misc File Opsxdb: Starting GUDyank: Kill Ringyank-pop: Earlier Killsyank-rectangle: Rectanglesyow: Amusementszap-to-char: Other Kill Commandszone: Amusementsabbrev-all-caps: Expanding Abbrevsabbrev-file-name: Saving Abbrevsabbrev-mode: Abbrev Conceptsadaptive-fill-first-line-regexp: Adaptive Filladaptive-fill-function: Adaptive Filladaptive-fill-mode: Adaptive Filladaptive-fill-regexp: Adaptive Filladd-log-always-start-new-record: Change Logadd-log-keep-changes-together: Change Logange-ftp-default-user: Remote Filesange-ftp-gateway-host: Remote Filesange-ftp-generate-anonymous-password: Remote Filesange-ftp-make-backup-files: Remote Filesange-ftp-smart-gateway: Remote Filesappt-audible: Appointmentsappt-delete-window-function: Appointmentsappt-disp-window-function: Appointmentsappt-display-diary: Appointmentsappt-display-duration: Appointmentsappt-display-format: Appointmentsappt-display-mode-line: Appointmentsappt-message-warning-time: Appointmentsapropos-do-all: Aproposapropos-documentation-sort-by-scores: Aproposapropos-sort-by-scores: Aproposauto-coding-alist: Recognize Codingauto-coding-functions: Recognize Codingauto-coding-regexp-alist: Recognize Codingauto-compression-mode: Compressed Filesauto-hscroll-mode: Horizontal Scrollingauto-mode-alist: Choosing Modesauto-revert-check-vc-info: VC Mode Lineauto-revert-interval: Revertingauto-save-default: Auto Save Controlauto-save-file-name-transforms: Auto Save Filesauto-save-interval: Auto Save Controlauto-save-list-file-prefix: Recoverauto-save-timeout: Auto Save Controlauto-save-visited-file-name: Auto Save Filesbackup-by-copying: Backup Copyingbackup-by-copying-when-linked: Backup Copyingbackup-by-copying-when-mismatch: Backup Copyingbackup-by-copying-when-privileged-mismatch: Backup Copyingbackup-directory-alist: Backup Namesbackup-enable-predicate: Backupbaud-rate: Display Custombdf-directory-list: PostScript Variablesblink-cursor-alist: Cursor Displayblink-matching-delay: Matchingblink-matching-paren: Matchingblink-matching-paren-distance: Matchingbookmark-save-flag: Bookmarksbookmark-search-size: Bookmarksbrowse-url-browser-function: Browse-URLbuffer-file-coding-system: Recognize Codingbuffer-read-only: Misc Bufferc-default-style: Custom C Indentc-hungry-delete-key: Hungry Deletec-mode-hook: Program Modesc-mode-map: Local Keymapsc-tab-always-indent: C Indentcalendar-daylight-savings-ends: Daylight Savingscalendar-daylight-savings-ends-time: Daylight Savingscalendar-daylight-savings-starts: Daylight Savingscalendar-daylight-time-offset: Daylight Savingscalendar-daylight-time-zone-name: Sunrise/Sunsetcalendar-latitude: Sunrise/Sunsetcalendar-location-name: Sunrise/Sunsetcalendar-longitude: Sunrise/Sunsetcalendar-standard-time-zone-name: Sunrise/Sunsetcalendar-time-zone: Sunrise/Sunsetcalendar-week-start-day: Move to Beginning or Endcase-fold-search: Search Casecase-replace: Replacement and Casechange-log-version-info-enabled: Change Logchange-log-version-number-regexp-list: Change Logchange-major-mode-with-file-name: Choosing Modescoding: Recognize Codingcolon-double-space: Fill Commandscomint-completion-addsuffix: Shell Optionscomint-completion-autolist: Shell Optionscomint-completion-fignore: Shell Modecomint-completion-recexact: Shell Optionscomint-input-autoexpand: History Referencescomint-input-ignoredups: Shell Optionscomint-move-point-for-output: Shell Optionscomint-prompt-read-only: Shell Optionscomint-prompt-regexp: Shell Promptscomint-scroll-show-maximum-output: Shell Optionscomint-scroll-to-bottom-on-input: Shell Optionscomint-use-prompt-regexp: Shell Promptscommand-history: Repetitioncommand-line-args: Emacs Invocationcomment-column: Options for Commentscomment-end: Options for Commentscomment-indent-function: Options for Commentscomment-multi-line: Options for Commentscomment-padding: Options for Commentscomment-start: Options for Commentscomment-start-skip: Options for Commentscompare-ignore-case: Comparing Filescompare-ignore-whitespace: Comparing Filescompilation-environment: Compilationcompilation-error-regexp-alist: Compilation Modecompilation-scroll-output: Compilationcompilation-skip-threshold: Compilation Modecompile-command: Compilationcompletion-auto-help: Completion Optionscompletion-ignored-extensions: Completion Optionsconfirm-kill-emacs: Exitingcrisp-override-meta-x: Emulationctl-arrow: Display Customctl-x-4-map: Prefix Keymapsctl-x-map: Prefix Keymapscua-enable-cua-keys: CUA Bindingscua-mode: CUA Bindingscurrent-input-method: Select Input Methodcurrent-language-environment: Language Environmentscursor-in-non-selected-windows: Cursor Displaycustom-buffer-done-function: Changing a Variablecustom-file: Saving Customizationscustom-theme-directory: Custom Themesdabbrev-abbrev-char-regexp: Dabbrev Customizationdabbrev-abbrev-skip-leading-regexp: Dabbrev Customizationdabbrev-case-fold-search: Dabbrev Customizationdabbrev-case-replace: Dabbrev Customizationdabbrev-check-all-buffers: Dynamic Abbrevsdabbrev-ignored-buffer-regexps: Dynamic Abbrevsdabbrev-limit: Dynamic Abbrevsdbx-mode-hook: GUD Customizationdefault-buffer-file-coding-system: Specify Codingdefault-case-fold-search: Search Casedefault-directory: File Namesdefault-enable-multibyte-characters: Enabling Multibytedefault-indicate-buffer-boundaries: Display Customdefault-indicate-empty-lines: Useless Whitespacedefault-input-method: Select Input Methoddefault-justification: Format Justificationdefault-major-mode: Choosing Modesdefault-tab-width: Display Customdelete-auto-save-files: Auto Save Filesdelete-old-versions: Backup Deletiondesktop-clear-preserve-buffers-regexp: Saving Emacs Sessionsdesktop-globals-to-clear: Saving Emacs Sessionsdesktop-restore-eager: Saving Emacs Sessionsdesktop-save-mode: Saving Emacs Sessionsdiary-file: Format of Diary Filediary-mail-days: Displaying the Diarydiary-outlook-formats: Importing Diarydiff-switches: Comparing Filesdirectory-free-space-args: Directoriesdirectory-free-space-program: Directoriesdired-chown-program: Operating on Filesdired-copy-preserve-time: Operating on Filesdired-dwim-target: Operating on Filesdired-garbage-files-regexp: Flagging Many Filesdired-kept-versions: Flagging Many Filesdired-listing-switches: Dired Enterdired-listing-switches (MS-DOS): MS-DOS Processesdired-recursive-copies: Operating on Filesdired-recursive-deletes: Dired Deletiondisplay-buffer-reuse-frames: Select Bufferdisplay-time-24hr-format: Optional Mode Linedisplay-time-mail-directory: Optional Mode Linedisplay-time-mail-face: Optional Mode Linedisplay-time-mail-file: Optional Mode Linedisplay-time-use-mail-icon: Optional Mode Linednd-open-file-other-window: Drag and Dropdos-codepage: MS-DOS and MULEdos-display-scancodes: MS-DOS Mousedos-hyper-key: MS-DOS Keyboarddos-keypad-mode: MS-DOS Keyboarddos-printer: MS-DOS Printingdos-ps-printer: MS-DOS Printingdos-super-key: MS-DOS Keyboarddos-unsupported-character-glyph: MS-DOS and MULEdouble-click-fuzz: Mouse Buttonsdouble-click-time: Mouse Buttonsecho-keystrokes: Display Customemacs-lisp-mode-hook: Program Modesemerge-combine-versions-template: Combining in Emergeemerge-startup-hook: Fine Points of Emergeenable-multibyte-characters: Enabling Multibyteenable-recursive-minibuffers: Minibuffer Editenriched-translations: Requesting Formatted Texteol-mnemonic-dos: Mode Lineeol-mnemonic-mac: Mode Lineeol-mnemonic-undecided: Mode Lineeol-mnemonic-unix: Mode Lineesc-map: Prefix Keymapseuropean-calendar-style: Date Formatseval-expression-debug-on-error: Lisp Evaleval-expression-print-length: Lisp Evaleval-expression-print-level: Lisp Evaleven-window-heights: Select Bufferexit-language-environment-hook: Language Environmentsexplicit-shell-file-name: Interactive Shellff-related-file-alist: Other C Commandsfile-coding-system-alist: Recognize Codingfile-name-buffer-file-type-alist: Text and Binaryfile-name-coding-system: Specify Codingfile-name-handler-alist: Remote Filesfill-column: Fill Commandsfill-nobreak-predicate: Fill Commandsfill-prefix: Fill Prefixfind-file-existing-other-name: File Aliasesfind-file-hook: Visitingfind-file-not-found-functions: Visitingfind-file-run-dired: Visitingfind-file-suppress-same-file-warnings: File Aliasesfind-file-visit-truename: File Aliasesfind-file-wildcards: Visitingfind-ls-option: Dired and Findfind-tag-marker-ring-length: Find Tagfocus-follows-mouse: Frame Commandsfoldout-mouse-modifiers: Foldoutfont-lock-beginning-of-syntax-function: Font Lockfont-lock-maximum-decoration: Font Lockfont-lock-maximum-size: Font Lockfortran-analyze-depth: ForIndent Contfortran-break-before-delimiters: Fortran Autofillfortran-check-all-num...: ForIndent Varsfortran-column-ruler-fixed: Fortran Columnsfortran-column-ruler-tabs: Fortran Columnsfortran-comment-indent-char: Fortran Commentsfortran-comment-indent-style: Fortran Commentsfortran-comment-line-extra-indent: Fortran Commentsfortran-comment-line-start: Fortran Commentsfortran-comment-region: Fortran Commentsfortran-continuation-indent: ForIndent Varsfortran-continuation-string: ForIndent Contfortran-directive-re: Fortran Commentsfortran-do-indent: ForIndent Varsfortran-electric-line-number: ForIndent Numfortran-if-indent: ForIndent Varsfortran-line-number-indent: ForIndent Numfortran-minimum-statement-indent...: ForIndent Varsfortran-structure-indent: ForIndent Varsfortran-tab-mode-default: ForIndent Contgdb-many-windows: GDB User Interface Layoutgdb-mode-hook: GUD Customizationgdb-show-changed-values: Watch Expressionsgdb-use-colon-colon-notation: Watch Expressionsgdb-use-inferior-io-buffer: Other GDB User Interface Buffersglobal-cwarn-mode: Other C Commandsglobal-font-lock-mode: Font Lockgrep-regexp-alist: Compilation Modegud-gdb-command-name: GDB Graphical Interfacegud-tooltip-echo-area: Debugger Operationgud-tooltip-mode: Debugger Operationgud-xdb-directories: Starting GUDhelp-at-pt-display-when-idle: Help Echohelp-map: Prefix Keymapshi-lock-exclude-modes: Highlight Interactivelyhighlight-nonselected-windows: Transient Markhistory-delete-duplicates: Minibuffer Historyhistory-length: Minibuffer Historyhourglass-delay: Display Customhs-hide-comments-when-hiding-all: Hideshowhs-isearch-open: Hideshowhs-special-modes-alist: Hideshowhscroll-margin: Horizontal Scrollinghscroll-step: Horizontal Scrollingimenu-auto-rescan: Imenuimenu-sort-function: Imenuindent-tabs-mode: Just Spacesindent-tabs-mode (Fortran mode): ForIndent Contindicate-buffer-boundaries: Display Customindicate-empty-lines: Useless Whitespaceinferior-lisp-program: External Lispinhibit-eol-conversion: Recognize Codinginhibit-iso-escape-detection: Recognize Codinginhibit-startup-buffer-menu: Action Argumentsinhibit-startup-message: Initial Optionsinitial-major-mode: Entering Emacsinput-method-highlight-flag: Input Methodsinput-method-verbose-flag: Input Methodsinsert-default-directory: File Namesinterpreter-mode-alist: Choosing Modesinverse-video: Display Customisearch-lazy-highlight: Highlight Isearchisearch-mode-map: Special Isearchisearch-resume-in-command-history: Repetitionispell-complete-word-dict: Spellingispell-dictionary: Spellingjdb-mode-hook: GUD Customizationkept-new-versions: Backup Deletionkept-old-versions: Backup Deletionkeyboard-coding-system: Specify Codingkill-buffer-hook: Kill Bufferkill-read-only-ok: Killingkill-ring: Earlier Killskill-ring-max: Earlier Killskill-whole-line: Killing by Lineskmacro-ring-max: Keyboard Macro Ringlarge-file-warning-threshold: Visitinglatex-block-names: LaTeX Editinglatex-mode-hook: TeX Misclatex-run-command: TeX Printlatin1-display: Undisplayable Charactersline-number-display-limit: Optional Mode Lineline-number-display-limit-width: Optional Mode Linelisp-body-indent: Lisp Indentlisp-indent-offset: Lisp Indentlisp-interaction-mode-hook: Program Modeslisp-mode-hook: Program Modeslisp-mode-map: Local Keymapslist-directory-brief-switches: Directorieslist-directory-verbose-switches: Directoriesload-dangerous-libraries: Lisp Librariesload-path: Lisp Librarieslocale-charset-language-names: Language Environmentslocale-coding-system: Specify Codinglocale-language-names: Language Environmentslocale-preferred-coding-systems: Language Environmentslocate-command: Dired and Findlpr-add-switches: Printinglpr-command (MS-DOS): MS-DOS Printinglpr-commands: Printinglpr-headers-switches: Printinglpr-headers-switches (MS-DOS): MS-DOS Printinglpr-switches: Printinglpr-switches (MS-DOS): MS-DOS Printingmac-allow-anti-aliasing: Mac Font Specsmac-command-modifier: Mac Inputmac-control-modifier: Mac Inputmac-emulate-three-button-mouse: Mac Inputmac-option-modifier: Mac Inputmac-pass-command-to-system: Mac Inputmac-pass-control-to-system: Mac Inputmac-wheel-button-is-mouse-2: Mac Inputmagic-mode-alist: Choosing Modesmail-abbrevs: Mail Aliasesmail-aliases: Mail Aliasesmail-archive-file-name: Mail Headersmail-default-directory: Sending Mailmail-default-headers: Mail Headersmail-default-reply-to: Mail Headersmail-from-style: Mail Headersmail-mode-hook: Mail Mode Miscmail-personal-alias-file: Mail Aliasesmail-self-blind: Mail Headersmail-setup-hook: Mail Mode Miscmail-signature: Mail Mode Miscmail-user-agent: Mail Methodsmail-yank-prefix: Citing Mailmake-backup-file-name-function: Backup Namesmake-backup-files: BackupMan-fontify-manpage-flag: Man PageMan-switches: Man Pagemark-diary-entries-in-calendar: Displaying the Diarymark-even-if-inactive: Transient Markmark-holidays-in-calendar: Holidaysmark-ring: Mark Ringmark-ring-max: Mark Ringmax-mini-window-height: Minibuffer Editmessage-log-max: Echo Areamidnight-hook: Kill Buffermidnight-mode: Kill Bufferminibuffer-local-completion-map: Minibuffer Mapsminibuffer-local-filename-completion-map: Minibuffer Mapsminibuffer-local-map: Minibuffer Mapsminibuffer-local-must-match-filename-map: Minibuffer Mapsminibuffer-local-must-match-map: Minibuffer Mapsminibuffer-local-ns-map: Minibuffer Mapsminibuffer-prompt-properties: Standard Facesmode-line-in-non-selected-windows: Optional Mode Linemode-require-final-newline: Customize Savemode-specific-map: Prefix Keymapsmouse-1-click-follows-link: Mouse Referencesmouse-1-click-in-non-selected-windows: Mouse Referencesmouse-autoselect-window: Other Windowmouse-avoidance-mode: Mouse Avoidancemouse-drag-copy-region: Mouse Commandsmouse-highlight: Mouse Referencesmouse-scroll-min-lines: Mouse Commandsmouse-wheel-follow-mouse: Wheeled Micemouse-wheel-progressive-speed: Wheeled Micemouse-wheel-scroll-amount: Wheeled Micemouse-yank-at-point: Mouse Commandsnext-error-highlight: Compilation Modenext-line-add-newlines: Moving Pointnext-screen-context-lines: Scrollingno-redraw-on-reenter: Display Customnobreak-char-display: Text Displaynormal-erase-is-backspace: DEL Does Not Deletenroff-mode-hook: Nroff Modeopen-paren-in-column-0-is-defun-start: Left Margin Parenoutline-level: Outline Formatoutline-minor-mode-prefix: Outline Modeoutline-mode-hook: Outline Modeoutline-regexp: Outline Formatoverflow-newline-into-fringe: Display Custompage-delimiter: Pagesparagraph-separate: Paragraphsparagraph-start: Paragraphspartial-completion-mode: Completion OptionsPC-disable-includes: Completion OptionsPC-include-file-path: Completion Optionspdb-mode-hook: GUD Customizationperldb-mode-hook: GUD Customizationpicture-mode-hook: Picturepicture-tab-chars: Tabs in Pictureplain-tex-mode-hook: TeX Miscprint-region-function (MS-DOS): MS-DOS Printingprinter-name: Printingprinter-name (MS-DOS): MS-DOS Printingps-font-family: PostScript Variablesps-font-info-database: PostScript Variablesps-font-size: PostScript Variablesps-landscape-mode: PostScript Variablesps-lpr-command: PostScript Variablesps-lpr-command (MS-DOS): MS-DOS Printingps-lpr-switches: PostScript Variablesps-lpr-switches (MS-DOS): MS-DOS Printingps-multibyte-buffer: PostScript Variablesps-number-of-columns: PostScript Variablesps-page-dimensions-database: PostScript Variablesps-paper-type: PostScript Variablesps-print-color-p: PostScript Variablesps-print-header: PostScript Variablesps-printer-name: PostScript Variablesps-printer-name (MS-DOS): MS-DOS Printingps-use-face-background: PostScript Variablesread-quoted-char-radix: Inserting Textrecentf-mode: File Conveniencesrequire-final-newline: Customize Saveresize-mini-windows: Minibuffer Editrevert-without-query: Revertingrmail-decode-mime-charset: Recognize Codingrmail-delete-after-output: Rmail Outputrmail-delete-message-hook: Rmail Deletionrmail-dont-reply-to-names: Rmail Replyrmail-edit-mode-hook: Rmail Editingrmail-file-coding-system: Recognize Codingrmail-file-name: Rmail Basicsrmail-highlighted-headers: Rmail Displayrmail-ignored-headers: Rmail Displayrmail-mail-new-frame: Rmail Replyrmail-mode-hook: Rmailrmail-movemail-flags: Remote Mailboxesrmail-movemail-program: Movemailrmail-movemail-search-path: Movemailrmail-output-file-alist: Rmail Outputrmail-pop-password: Remote Mailboxesrmail-pop-password-required: Remote Mailboxesrmail-preserve-inbox: Rmail Inboxrmail-primary-inbox-list: Rmail Inboxrmail-redisplay-summary: Rmail Summary Editrmail-remote-password: Remote Mailboxesrmail-remote-password-required: Remote Mailboxesrmail-retry-ignored-headers: Rmail Replyrmail-secondary-file-directory: Rmail Filesrmail-secondary-file-regexp: Rmail Filesrmail-summary-line-count-flag: Rmail Make Summaryrmail-summary-window-size: Rmail Make Summarysame-window-buffer-names: Force Same Windowsame-window-regexps: Force Same Windowsave-abbrevs: Saving Abbrevsscheme-mode-hook: Program Modesscroll-all-mode: Window Conveniencescroll-bar-mode: Scroll Barsscroll-bar-width: Scroll Barsscroll-conservatively: Scrollingscroll-down-aggressively: Scrollingscroll-margin: Scrollingscroll-preserve-screen-position: Scrollingscroll-up-aggressively: Scrollingsdb-mode-hook: GUD Customizationsearch-slow-speed: Slow Isearchsearch-slow-window-lines: Slow Isearchsearch-whitespace-regexp: Regexp Searchselective-display-ellipses: Selective Displaysend-mail-function: Mail Sendingsendmail-coding-system: Recognize Codingsentence-end: Sentencessentence-end-double-space: Fill Commandssentence-end-without-period: Fill Commandsserver-kill-new-buffers: Emacs Serverserver-name: Emacs Serverserver-temp-file-regexp: Emacs Serverserver-window: Emacs Serverset-language-environment-hook: Language Environmentsset-mark-command-repeat-pop: Mark Ringsgml-xml-mode: HTML Modeshell-cd-regexp: Directory Trackingshell-command-default-error-buffer: Single Shellshell-command-regexp: Shell Modeshell-completion-execonly: Shell Optionsshell-completion-fignore: Shell Modeshell-file-name: Single Shellshell-input-ring-file-name: Shell Ringshell-popd-regexp: Directory Trackingshell-prompt-pattern: Shell Promptsshell-pushd-regexp: Directory Trackingshow-trailing-whitespace: Useless Whitespaceslitex-mode-hook: TeX Miscslitex-run-command: TeX Printsmall-temporary-file-directory: Backupsort-fold-case: Sortingsort-numeric-base: Sortingspecial-display-buffer-names: Special Buffer Framesspecial-display-frame-alist: Special Buffer Framesspecial-display-regexps: Special Buffer Framessplit-window-keep-point: Split Windowstandard-fontset-spec: Defining Fontsetsstandard-indent: Format Indentationsuggest-key-bindings: M-xtab-stop-list: Tab Stopstab-width: Display Customtable-cell-horizontal-char: Table Definitiontable-cell-intersection-char: Table Definitiontable-cell-vertical-char: Table Definitiontable-detect-cell-alignment: Cell Justificationtags-apropos-additional-actions: List Tagstags-apropos-verbose: List Tagstags-case-fold-search: Tags Searchtags-file-name: Select Tags Tabletags-table-list: Select Tags Tabletags-tag-face: List Tagstemporary-file-directory: Backupterm-file-prefix: Terminal Initterm-setup-hook: Terminal Inittex-bibtex-command: TeX Printtex-default-mode: TeX Modetex-directory: TeX Printtex-dvi-print-command: TeX Printtex-dvi-view-command: TeX Printtex-main-file: TeX Printtex-mode-hook: TeX Misctex-run-command: TeX Printtex-shell-hook: TeX Misctex-show-queue-command: TeX Printtex-start-commands: TeX Printtex-start-options: TeX Printtext-mode-hook: Text Modetimeclock-ask-before-exiting: Time Intervalstimeclock-file: Time Intervalstimeclock-modeline-display: Time Intervalstooltip-delay: Tooltipstooltip-gud-modes: Debugger Operationtrack-eol: Moving Pointtruncate-lines: Display Customtruncate-partial-width-windows: Split Windowundo-limit: Undoundo-outer-limit: Undoundo-strong-limit: Undounibyte-display-via-language-environment: Single-Byte Character Supportuniquify-buffer-name-style: Uniquifyuse-dialog-box: Dialog Boxesuse-file-dialog: Dialog Boxesuser-mail-address: Init Examplesvc-backend-header: Version Headersvc-command-messages: General VC Optionsvc-comment-alist: Version Headersvc-consult-headers: RCS and SCCSvc-cvs-global-switches: CVS Optionsvc-cvs-stay-local: CVS Optionsvc-default-init-version: Registeringvc-diff-switches: Old Versionsvc-directory-exclusion-list: VC Dired Modevc-dired-recurse: VC Dired Modevc-dired-terse-display: VC Dired Modevc-follow-symlinks: General VC Optionsvc-handled-backends: Customizing VCvc-initial-comment: Registeringvc-keep-workfiles: General VC Optionsvc-log-mode-hook: Log Buffervc-make-backup-files: General VC Optionsvc-make-backup-files: Backupvc-mistrust-permissions: RCS and SCCSvc-path: General VC Optionsvc-rcs-diff-switches: Old Versionsvc-static-header-alist: Version Headersvc-suppress-confirm: General VC Optionsversion-control: Backup Namesview-calendar-holidays-initially: Holidaysview-diary-entries-initially: Displaying the Diaryvisible-bell: Display Customw32-pass-alt-to-system: Windows System Menuwhich-func-modes: Which Functionwindow-min-height: Change Windowwindow-min-width: Change Windowwoman-dired-keys: Man Pagewoman-manpath: Man Pagewoman-path: Man Pagewrite-region-inhibit-fsync: Customize Savex-cut-buffer-max: Mouse Commandsx-mouse-click-focus-ignore-position: Mouse Commandsx-select-enable-clipboard: Clipboardx-stretch-cursor: Cursor Displayx-use-old-gtk-file-dialog: Dialog Boxesxdb-mode-hook: GUD Customizationyank-excluded-properties: Kill Ring$ in file names: File Namesaddpm, MS-Windows installation program: MS-Windows Registryarc: File Archivesb2m: Out of Rmailcomint-highlight-input face: Interactive Shellcomint-highlight-prompt face: Interactive Shelldiff3): Comparing Filesmenu face: Standard Facescvs: VC Dired ModeEdebug: Checklistemacs.bash: Invoking emacsclientemacsclient: Emacs Serveretags program: Create Tags Tablefind: File Name Cachefind and Dired: Dired and Findfringe face: Standard Facesange-ftp: Remote Filesgzip: Compressed Filesiso-ascii library: Single-Byte Character Supportiso-transl library: Single-Byte Character Supportispell program: Spellingjar: File Archiveslisp-indent-function property: Lisp Indentlzh: File Archivesmenu face, no effect if customized: Standard Facesminibuffer-prompt face: Standard Facesmovemail: Remote Mailboxesmovemail program: Movemailregion face: Standard Faceszip: File Archiveszoo: File Archivesmovemail program
find
[1] This manual is itself covered by the GNU Free Documentation License. This license is similar in spirit to the General Public License, but is more suitable for documentation. See GNU Free Documentation License.
[2] Buffers which don't visit files and whose names begin with a space are omitted: these are used internally by Emacs.
[3] Some systems use Mouse-3 for a mode-specific
menu. We took a survey of users, and found they preferred to keep
Mouse-3 for selecting and killing regions. Hence the decision
to use C-Mouse-3 for this menu. To use Mouse-3 instead,
do (global-set-key [mouse-3] 'mouse-popup-menubar-stuff).
[4] See the X Window System documentation for more details. On a typical GNU or Unix system, the command man 7 X or man -s 7 X will display the X manual page that explains how to specify colors.
[5] Placing it at the left is usually more useful with overlapping frames with text starting at the left margin.
[6] If you run Emacs on X, you need to inform the X server about the location of the newly installed fonts with the following commands:
xset fp+ /usr/local/share/emacs/fonts
xset fp rehash
[7] If more than one of these is set, the first one that is nonempty specifies your locale for this purpose.
[8]
In the MS-DOS port of Emacs, you need to create a cpnnn
coding system with M-x codepage-setup, before you can use it.
See MS-DOS and MULE.
[9] It is also specified for MIME ‘text/*’ bodies and in other network transport contexts. It is different from the SGML reference syntax record-start/record-end format which Emacs doesn't support directly.
[10] The Emacs installation instructions have information on additional font support.
[11] SliTeX is obsoleted by the ‘slides’ document class in recent LaTeX versions.
[12] Alternatively, you can set up C Mode to recognize a defun at an opening brace at the outermost level. See Movement Commands.
[13] The word “sexp” is used to refer to an expression in Lisp.
[14] On some systems, the man program
accepts a ‘-a’ command-line option which tells it to display all
the man pages for the specified topic. If you want this behavior, you
can add this option to the value of the variable Man-switches.
[15] The name of the command, woman, is an acronym
for “w/o (without) man,” since it doesn't use the man
program.
[16] This command had the binding
C-c C-d in earlier versions of Emacs. C-c C-d is now
bound to c-hungry-delete-forward.
[17] Under a window system, the arrow appears in the left fringe of the Emacs window.
[18] The US National Security Agency.
[19] You should not suspend the shell process. Suspending a subjob of the shell is a completely different matter—that is normal practice, but you must use the shell to continue the subjob; this command won't do it.
[20] This dissociword actually appeared during the Vietnam War, when it was very appropriate.
[21] Note that you should avoid the string syntax for binding non-ASCII characters, since they will be interpreted as meta keys. See Strings of Events.
[22] Here and below, whenever we say “colon-separated list of directories,” it pertains to Unix and GNU/Linux systems. On MS-DOS and MS-Windows, the directories are separated by semi-colons instead, since DOS/Windows file names might include a colon after a drive letter.
[23]
Note that the ‘net use’ command requires the UNC share name to be
typed with the Windows-style backslashes, while the value of
printer-name can be set with either forward- or backslashes.
[24] Normally, one particular codepage is burnt into the display memory, while other codepages can be installed by modifying system configuration files, such as CONFIG.SYS, and rebooting. While there is third-party software that allows changing the codepage without rebooting, we describe here how a stock MS-DOS system behaves.
[25] The standard Emacs coding systems for ISO 8859 are not quite right for the purpose, because typically the DOS codepage does not match the standard ISO character codes. For example, the letter ‘ç’ (‘c’ with cedilla) has code 231 in the standard Latin-1 character set, but the corresponding DOS codepage 850 uses code 135 for this glyph.
[26] The wording here was careless. The intention was that nobody would have to pay for permission to use the GNU system. But the words don't make this clear, and people often interpret them as saying that copies of GNU should always be distributed at little or no charge. That was never the intent; later on, the manifesto mentions the possibility of companies providing the service of distribution for a profit. Subsequently I have learned to distinguish carefully between “free” in the sense of freedom and “free” in the sense of price. Free software is software that users have the freedom to distribute and change. Some users may obtain copies at no charge, while others pay to obtain copies—and if the funds help support improving the software, so much the better. The important thing is that everyone who has a copy has the freedom to cooperate with others in using it.
[27] This is another place I failed to distinguish carefully between the two different meanings of “free.” The statement as it stands is not false—you can get copies of GNU software at no charge, from your friends or over the net. But it does suggest the wrong idea.
[28] Several such companies now exist.
[29] The Free Software Foundation raises most of its funds from a distribution service, although it is a charity rather than a company. If no one chooses to obtain copies by ordering from the FSF, it will be unable to do its work. But this does not mean that proprietary restrictions are justified to force every user to pay. If a small fraction of all the users order copies from the FSF, that is sufficient to keep the FSF afloat. So we ask users to choose to support us in this way. Have you done your part?
[30] A group of computer companies recently pooled funds to support maintenance of the GNU C Compiler.
[31] In the 80s I had not yet realized how confusing it was to speak of “the issue” of “intellectual property.” That term is obviously biased; more subtle is the fact that it lumps together various disparate laws which raise very different issues. Nowadays I urge people to reject the term “intellectual property” entirely, lest it lead others to suppose that those laws form one coherent issue. The way to be clear is to discuss patents, copyrights, and trademarks separately. See http://www.gnu.org/philosophy/not-ipr.xhtml for more explanation of how this term spreads confusion and bias.
[32] Subsequently we have learned to distinguish between "free software" and "freeware". The term "freeware" means software you are free to redistribute, but usually you are not free to study and change the source code, so most of it is not free software. See http://www.gnu.org/philosophy/words-to-avoid.html for more explanation.