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@(#)mt.1 8.1 (Berkeley) 6/6/93
.Dd June 6, 1993 .Dt MT 1 .Os BSD 4 .Sh NAME .Nm mt .Nd magnetic tape manipulating program .Sh SYNOPSIS .Nm .Op Fl f Ar tapename .Ar command .Op Ar count .Sh DESCRIPTION .Nm is used to give commands to a magnetic tape drive. By default .Nm performs the requested operation once. Operations may be performed multiple times by specifying .Ar count . Note that .Ar tapename must reference a raw (not block) tape device. If .Ar tapename is of the form .Dq host:tapename , or .Dq user@host:tapename , .Nm writes to the named tape device on the remote host using .Xr rmt 8 .
p The available commands are listed below. Only as many characters as are required to uniquely identify a command need be specified. l -tag -width "eof, weof" t Cm asf Absolute space to file .Ar count . t Cm eof , weof Write .Ar count end-of-file marks at the current position on the tape. t Cm fsf Forward space .Ar count files. t Cm fsr Forward space .Ar count records. t Cm bsf Back space .Ar count files. t Cm bsr Back space .Ar count records. t Cm rewind Rewind the tape (Count is ignored). t Cm offline , rewoffl Rewind the tape and place the tape unit off-line (Count is ignored). t Cm status Print status information about the tape unit (Count is ignored). t Cm retension Retensions the tape (if this operation is supported by the tape unit, count is ignored). t Cm erase Erases the tape (if this operation is supported by the tape unit, count is ignored). t Cm eom Forward space to the end of the media (Count is ignored). t Cm blocksize Set the tape blocksize to .Ar count bytes. A .Ar count of zero sets variable blocksize. t Cm density Set the tape density code to .Ar count as specified in the SCSI2 specification. t Cm rdspos Read the logical block position of the tape (not all tape drives support this feature, count is ignored). t Cm rdhpos Read the hardware block position of the tape (not all tape drives support this feature, count is ignored). t Cm setspos Set the logical block position of the tape to .Ar count (not all tape drives support this feature). t Cm sethpos Set the hardware block position of the tape to .Ar count (not all tape drives support this feature). t Cm compress If .Ar count is zero, disable compression. Otherwise enable compression (not all tape drives support this feature). .El
p If a tape name is not specified, and the environment variable .Ev TAPE is not set, then .Nm uses the device
p
.Nm
returns a 0 exit status when the operation(s) were successful,
1 if the command was unrecognized, and 2 if an operation failed.
.Sh ENVIRONMENT
If the following environment variable exists, it is utilized by
.Nm "" .
l -tag -width Fl t Ev TAPE .Nm
checks the
.Ev TAPE
environment variable if the
argument
.Ar tapename
is not given.
.Sh FILES
l -tag -width src/sys/dev/scsipi/scsi_tape.h -compact t Pa /dev/rst* Raw SCSI tape interface
t Pa /dev/rmt* Raw magnetic tape interface
t Pa src/sys/dev/scsipi/scsi_tape.h List of SCSI2 density codes
.El
.Sh SEE ALSO
.Xr dd 1 ,
.Xr ioctl 2 ,
.Xr mtio 4 ,
.Xr environ 7
.Sh HISTORY
The
.Nm
utility appeared in
x 4.3 . mt.1: mtio(4) missing
Indexes created Wed Oct 22 13:09:56 GMT 2025