NAME

mt − magnetic tape manipulating program

SYNOPSIS

mt [ −f tapename ] command [ count ]

DESCRIPTION

Mt is used to give commands to a magnetic tape drive.  If a tape name is not specified, the environment variable TAPE is used;  if TAPE does not exist, mt uses the device /dev/rmt12. Note that tapename must reference a raw (not block) tape device.  By default mt performs the requested operation once.  Operations may be performed multiple times by specifying count.

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.) 

retension, ret
Retension the tape. This command is used for streamer tapes and should be done once per data access on 5 ¼” drives to minimize tape stretch.

eod, seod
Spaces to end of valid data. Used (possibly mandatory) on streamer tape drives to append data to the logical end of tape.

noret Don’t retension the tape this time.  Streamer tapes are normally retensioned once on the first physical I/O operation following insertion of the tape into the drive.  To disable this automatic retensioning, issue this command between inserting the tape and beginning I/O operations.  Automatic tape retensioning will resume with the next tape insertion. 

status
Print status information about the tape unit.

erase Erase the tape. 

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

FILES

/dev/rmt∗Raw magnetic tape interface

SEE ALSO

mtio(4), dd(1), ioctl(2), environ(7)

BUGS

−t is a synonym for −f on the command line, for backwards compatibility. 

4BSD/DYNIX