The
mt program 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
rmt(8) process on the remote host is typically initiated via
rsh(1), although an alternate method such as
ssh(1) can be specified via the
RCMD_CMD environment variable.
The available commands are listed below. Only as many characters as are required to uniquely identify a command need be specified.
asf
Move forward count files from the beginning of the tape. This is accomplished by a rewind followed by fsf 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. (The count is ignored.)
offline, rewoffl
Rewind the tape and place the tape unit off-line. Where supported, this ejects the tape. (The count is ignored.)
status
Print status information about the tape unit. (The count is ignored.)
retension
Retensions the tape. Not all tape drives support this feature. (The count is ignored.)
erase
Erases the tape Not all tape drives support this feature. (The count is ignored.)
eew
Enable or disable early warning EOM behaviour. Set count to nonzero to enable, zero to disable.
eom
Forward space to the end of recorded media. (The count is ignored.)
blocksize, setblk
Set the tape blocksize to count bytes. A count of zero sets variable blocksize.
density, setdensity
Set the tape density code to
count as specified in the SCSI-3 specification. See the
DENSITY CODES section for a list of codes for commonly used media types.
rdspos
Read the logical block position of the tape. Not all tape drives support this feature. (The count is ignored.)
rdhpos
Read the hardware block position of the tape. Not all tape drives support this feature. (The 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.