mt1

Usage

Overview

The mt utility sends commands to a magnetic tape drive. By default, mt performs the requested operation once. Operations may be performed multiple times by specifying count. Note that device must reference a raw (not block) tape device. If device is of the form “host:device” or “user@host:device”, mt writes to the named tape device on the remote host using rmt(8). eject is simply an alias for mt, with the offline command specified. eject may also be used to eject other types of removable media.

The options for mt are as follows:

-f device

Operate on the device specified.

The options for eject are as follows:

-t

Insert the device instead of ejecting. For the cd(4) driver, this requests that the tray be closed.

The available commands are listed below. Only as many characters as are required to uniquely identify a command need be specified.

eof, weof

Write count end-of-file marks at the current position on the tape.

fsf

Forward space count files.

fsr

Forward space count records.

bsf

Back space count files.

bsr

Back space count records.

rewind

Rewind the tape (count is ignored).

offline, rewoffl

Rewind the tape and place the tape unit off-line (count is ignored). On non-tape removable media, the offline command causes the media to be ejected when the last operation on it closes (i.e., the filesystem is unmounted).

status

Print status information about the tape unit.

retension

Retension the tape (if this operation is supported by the tape unit).

erase

Erase the tape (if this operation is supported by the tape unit).

eom

Forward space to the end of the media.

blocksize

Set the tape blocksize to count bytes.

density

Set the tape density code to count as specified in the SCSI2 specification.

If a tape name is not specified, and the environment variable TAPE does not exist, mt uses the device /dev/rst0. The TAPE variable is ignored by eject.

Environment

If the following environment variable exists, it is utilized by mt.

TAPE

mt checks the TAPE environment variable if the argument device is not given.

Files

/dev/rst*

raw SCSI tape interface

/usr/src/sys/scsi/scsi_tape.h

list of SCSI2 density codes

Exit status

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

Examples

Eject the first CD device. This will work even if there is no CD in the drive:

$ eject /dev/rcd0c