Manual browser: mt(1)
|MT(1)||General Commands Manual||MT(1)|
NAMEmt — magnetic tape manipulation
|mt||[-f tapename] command [count]|
DESCRIPTIONThe 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 available commands are listed below. Only as many characters as are required to uniquely identify a command need be specified.
- 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.
- Forward space count files.
- Forward space count records.
- Back space count files.
- Back space count records.
- 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.)
- Print status information about the tape unit. (The count is ignored.)
- Retensions the tape. Not all tape drives support this feature. (The count is ignored.)
- Erases the tape Not all tape drives support this feature. (The count is ignored.)
- Enable or disable early warning EOM behaviour. Set count to nonzero to enable, zero to disable.
- 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.
- Read the logical block position of the tape. Not all tape drives support this feature. (The count is ignored.)
- Read the hardware block position of the tape. Not all tape drives support this feature. (The count is ignored.)
- Set the logical block position of the tape to count. Not all tape drives support this feature.
- Set the hardware block position of the tape to count. Not all tape drives support this feature.
- 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.
ENVIRONMENTIf the following environment variables exist, they are used by mt.
- mt uses device filename given in the TAPE environment variable if the tapename argument is not given.
- mt will use RCMD_CMD rather than /usr/bin/rsh to invoke rmt(8) on a remote machine. The full path name must be specified.
- Raw SCSI tape device
- Raw magnetic tape device
EXIT STATUSmt returns a 0 exit status when the operation(s) were successful, 1 if the command was unrecognized, and 2 if an operation failed.
DENSITY CODESThe SCSI-3 specification defines a number of density codes for various tape media, some of which are listed here. Note that many tape drive vendors also define model-specific codes.
||1/2" 800 bpi|
||1/2" 1600 bpi|
||1/2" 6250 bpi|
HISTORYThe mt utility appeared in 4.3BSD.
|March 9, 2008||NetBSD 7.0|