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MT(1)                       NetBSD Reference Manual                      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 per-
     forms 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 ig-
                nored).

     status     Print status information about the tape unit (Count is ig-
                nored).

     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 com-
                pression (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 mt.

     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.

4th Berkeley Distribution        June 6, 1993                                2