NetBSD/bin/mt/mt.1

.\"	$NetBSD: mt.1,v 1.13 1997/10/04 12:32:31 hannken Exp $
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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 mt
.Op Fl f Ar tapename
.Ar command
.Op Ar count
.Sh DESCRIPTION
.Nm Mt
is used to give commands to a magnetic tape drive.
By default
.Nm mt
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 mt
writes to the named tape device on the remote host using
.Xr rmt 8 .
.Pp
The available commands are listed below.  Only as many
characters as are required to uniquely identify a command
need be specified.
.Bl -tag -width "eof, weof"
.It Cm asf
Absolute space to
file
.Ar count .
.It Cm eof , weof
Write
.Ar count
end-of-file marks at the current position on the tape.
.It Cm fsf
Forward space
.Ar count
files.
.It Cm fsr
Forward space
.Ar count
records.
.It Cm bsf
Back space
.Ar count
files.
.It Cm bsr
Back space
.Ar count
records.
.It Cm rewind
Rewind the tape
(Count is ignored).
.It Cm offline , rewoffl
Rewind the tape and place the tape unit off-line
(Count is ignored).
.It Cm status
Print status information about the tape unit
(Count is ignored).
.It Cm retension
Retensions the tape (if this operation is supported by the tape unit,
count is ignored).
.It Cm erase
Erases the tape (if this operation is supported by the tape unit,
count is ignored).
.It Cm eom
Forward space to the end of the media
(Count is ignored).
.It Cm blocksize
Set the tape blocksize to
.Ar count
bytes.
A
.Ar count
of zero sets variable blocksize.
.It Cm density
Set the tape density code to
.Ar count
as specified in the SCSI2 specification.
.It Cm rdspos
Read the logical block position of the tape (not all tape
drives support this feature, count is ignored).
.It Cm rdhpos
Read the hardware block position of the tape (not all tape
drives support this feature, count is ignored).
.It Cm setspos
Set the logical block position of the tape to
.Ar count
(not all tape drives support this feature).
.It Cm sethpos
Set the hardware block position of the tape to
.Ar count
(not all tape drives support this feature).
.It Cm compress
If
.Ar count
is zero, disable compression.  Otherwise enable compression (not all tape
drives support this feature).
.El
.Pp
If a tape name is not specified, and the environment variable
.Ev TAPE
is not set, then
.Nm mt
uses the device
.Pa /dev/nrst0 .
.Pp
.Nm Mt
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 mt .
.Bl -tag -width Fl
.It Ev TAPE
.Nm Mt
checks the
.Ev TAPE
environment variable if the
argument
.Ar tapename
is not given.
.Sh FILES
.Bl -tag -width src/sys/dev/scsipi/scsi_tape.h -compact
.It Pa /dev/rst*
Raw SCSI tape interface
.It Pa /dev/rmt*
Raw magnetic tape interface
.It 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 mt
utility appeared in
.Bx 4.3 .
.\" mt.1: mtio(4) missing