OpenBSD-4.6/bin/mt/mt.1

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.\"	$OpenBSD: mt.1,v 1.27 2007/11/03 09:05:33 jmc Exp $
.\"	$NetBSD: mt.1,v 1.8 1996/05/21 10:23:55 mrg Exp $
.\"
.\" Copyright (c) 1981, 1990, 1993
.\"	The Regents of the University of California.  All rights reserved.
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.\"	@(#)mt.1	8.1 (Berkeley) 6/6/93
.\"
.Dd $Mdocdate: November 3 2007 $
.Dt MT 1
.Os
.Sh NAME
.Nm mt ,
.Nm eject
.Nd magnetic tape and removable media manipulating program
.Sh SYNOPSIS
.Nm mt
.Op Fl f Ar device
.Ar command
.Op Ar count
.Nm eject
.Op Fl t
.Ar device
.Sh DESCRIPTION
The
.Nm
utility sends 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 device
must reference a raw (not block) tape device.
If
.Ar device
is of the form
.Dq host:device
or
.Dq user@host:device ,
.Nm
writes to the named tape device on the remote host using
.Xr rmt 8 .
.Nm eject
is simply an alias for
.Nm mt ,
with the
.Cm offline
command specified.
.Nm eject
may also be used to eject other types of removable media.
.Pp
The options for
.Nm
are as follows:
.Bl -tag -width Ds
.It Fl f Ar device
Operate on the
.Ar device
specified.
.El
.Pp
The options for
.Nm eject
are as follows:
.Bl -tag -width Ds
.It Fl t
Insert the device instead of ejecting.
For the
.Xr cd 4
driver, this requests that the tray be closed.
.El
.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 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
.Pq Ar count Li is ignored .
.It Cm offline , rewoffl
Rewind the tape and place the tape unit off-line
.Pq Ar count Li is ignored .
On non-tape removable media, the
.Cm offline
command causes the media to be ejected when the last operation on it
closes (i.e., the filesystem is unmounted).
.It Cm status
Print status information about the tape unit.
.It Cm retension
Retension the tape (if this operation is supported by the tape unit).
.It Cm erase
Erase the tape (if this operation is supported by the tape unit).
.It Cm eom
Forward space to the end of the media.
.It Cm blocksize
Set the tape blocksize to
.Ar count
bytes.
.It Cm density
Set the tape density code to
.Ar count
as specified in the SCSI2 specification.
.El
.Pp
If a tape name is not specified, and the environment variable
.Ev TAPE
does not exist,
.Nm
uses the device
.Pa /dev/rst0 .
The
.Ev TAPE
variable is ignored by
.Nm eject .
.Pp
.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 mt .
.Bl -tag -width Fl
.It Ev TAPE
.Nm
checks the
.Ev TAPE
environment variable if the
argument
.Ar device
is not given.
.El
.Sh FILES
.Bl -tag -width /usr/src/sys/scsi/scsi_tape.h -compact
.It Pa /dev/rst*
raw SCSI tape interface
.It Pa /dev/rmt*
raw magnetic tape interface
.It Pa /usr/src/sys/scsi/scsi_tape.h
list of SCSI2 density codes
.El
.Sh EXAMPLES
Eject the first CD device.
This will work even if there is no CD in the drive:
.Pp
.Dl $ eject /dev/rcd0c
.Sh SEE ALSO
.Xr cdio 1 ,
.Xr chio 1 ,
.Xr dd 1 ,
.Xr ioctl 2 ,
.Xr mtio 4
.Sh HISTORY
The
.Nm
utility appeared in
.At v2 .