9.5.2 The mt Utility

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See Blocking Factor.

You can use the mt utility to advance or rewind a tape past a specified number of archive files on the tape. This will allow you to move to the beginning of an archive before extracting or reading it, or to the end of all the archives before writing a new one.

The syntax of the mt command is:

     mt [-f tapename] operation [number]

where tapename is the name of the tape device, number is the number of times an operation is performed (with a default of one), and operation is one of the following:

eof

weof

Writes number tape marks at the current position on the tape.

fsf

Moves tape position forward number files.

bsf

Moves tape position back number files.

rewind

Rewinds the tape. (Ignores number).

offline

rewoff1

Rewinds the tape and takes the tape device off-line. (Ignores number).

status

Prints status information about the tape unit.

If you don't specify a tapename, mt uses the environment variable TAPE; if TAPE is not set, mt will use the default device specified in your sys/mtio.h file (DEFTAPE variable). If this is not defined, the program will display a descriptive error message and exit with code 1.

mt returns a 0 exit status when the operation(s) were successful, 1 if the command was unrecognized, and 2 if an operation failed.