MT(1)

NAME
mt - magnetic tape manipulating program

SYNOPSIS
mt [-f tapename] command [count]

DESCRIPTION
mt is used to give 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 tapename must reference a raw (not block) tape device. If tapename is of the form “host:tapename”, or “user@host:tapename”, mt writes to the named tape device on the remote host using rmt(8).

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

asf Absolute space to file count.

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).

status
    Print status information about the tape unit (Count is ignored).

retension
    Retensions the tape (if this operation is supported by the tape unit, count is ignored).

erase
    Erases the tape (if this operation is supported by the tape unit, count is ignored).

eom Forward space to the end of the media (Count is ignored).

blocksize
    Set the tape blocksize to count bytes. A count of zero sets variable blocksize.

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

rdspos
    Read the logical block position of the tape (not all tape drives support this feature, count is ignored).

rdhpos
    Read the hardware block position of the tape (not all tape drives support this feature, count is ignored).

setspos
    Set the logical block position of the tape to count (not all tape drives support this feature).

sethpos
    Set the hardware block position of the tape to count (not all tape drives support this feature).

compress
    If count is zero, disable compression. Otherwise enable compression (not all tape drives support this feature).

If a tape name is not specified, and the environment variable TAPE is not set, then mt uses the device /dev/nrst0.

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

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

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

FILES
/dev/rst*
    Raw SCSI tape interface
/dev/rmt*
    Raw magnetic tape interface
src/sys/dev/scsipi/scsi_tape.h
    List of SCSI2 density codes

SEE ALSO
dd(1), ioctl(2), environ(7)

HISTORY
The mt utility appeared in 4.3BSD.