Most PSPP commands share a common structure. A command begins with a command name, such as FREQUENCIES, DATA LIST, or N OF CASES. The command name may be abbreviated to its first word, and each word in the command name may be abbreviated to its first three or more characters, where these abbreviations are unambiguous.
The command name may be followed by one or more subcommands. Each subcommand begins with a subcommand name, which may be abbreviated to its first three letters. Some subcommands accept a series of one or more specifications, which follow the subcommand name, optionally separated from it by an equals sign (=). Specifications may be separated from each other by commas or spaces. Each subcommand must be separated from the next (if any) by a forward slash (/).
There are multiple ways to mark the end of a command. The most common way is to end the last line of the command with a period (.) as described in the previous section (see Tokens). A blank line, or one that consists only of white space or comments, also ends a command by default, although you can use the NULLINE subcommand of SET to disable this feature (see SET).
In batch mode only, that is, when reading commands from a file instead of an interactive user, any line that contains a non-space character in the leftmost column begins a new command. Thus, each command consists of a flush-left line followed by any number of lines indented from the left margin. In this mode, a plus sign, minus sign, or period (+, −, or .) as the first character in a line is ignored and causes that line to begin a new command, which allows for visual indentation of a command without that command being considered part of the previous command.
Sometimes, one encounters syntax files that are intended to be interpreted in interactive mode rather than batch mode. When this occurs, use the -i command line option to force interpretation in interactive mode (see Language control options).