mt.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)mt.1	3.2	5/11/88
.TH mt 1
.SH Name
mt \- magnetic tape manipulating program
.SH Syntax
.B mt
[\fB\-f\fI tapename\fR\|] \fIcommand\fR [\|\fIcount\fR\|]
.SH Description
.NXR "mt program"
.NXR "magnetic tape" "manipulating"
The
.PN mt
command
permits the operation of a magnetic tape drive.
.SH Options
The \fB\-f\fR flag 
option uses the specified tape device (next argument) in
place of either that tape device defined by your TAPE
environment variable (.login or .profile) or /dev/nrmt0h.
.PP
Some operations
may be performed multiple times by specifying
.IR count .
By default,
.PN mt
performs the requested operation once.
.PP
The \fIcommand\fR argument defines the operation to be performed.
Only as many characters as are required to uniquely identify
a command need be specified.  
.PP
The following is a list of commands:
.NXR "mt program" "command list"
.IP \fBbsf\fR 20
.NXR "bsf command (mt)"
Backspace \fIcount\fR files.
.IP \fBbsr\fR
.NXR "bsr command (mt)"
Backspace \fIcount\fR records.
.IP \fBcache\fR
.NXR "cache command (mt)"
Allows 
.PN mt
to use the cache buffer on a tape drive that has the cache
buffer feature.
.IP \fBclhrdsf\fR
.NXR "clhrdsf command (mt)"
Clear hardware/software problem.  Works with 
tape drives which use the TMSCP tape controller interface
.MS tms 4 .
This command is restricted to root access only.
.IP \fBclserex\fR
.NXR "clserex command (mt)"
Clear serious exception.  Works with 
tape drives which use the TMSCP tape controller interface
.MS tms 4 .
.IP \fBclsub\fR
.NXR "clsub command (mt)"
Clear subsystem.  Works with tape drives which use the TMSCP tape
controller interface
.MS tms 4 .
This command is restricted to root access only.
.IP "\fBeof, weof\fR"
.NXR "eof command (mt)"
.NXR "weof command (mt)"
Write \fIcount\fR end-of-file marks at the current position on
the tape.
.IP \fBeotdis\fR
.NXR "eotdis command (mt)"
Disable end-of-tape detection.  When the end of tape
is reached, the tape will run off the reel.  Only the superuser 
can issue this command.  The command remains in effect 
for the device until end-of-tape detection is enabled
with the \fBeoten\fR command.
.IP \fBeoten\fR
.NXR "eoten command (mt)"
Enable end-of-tape detection.  When the end-of-tape
markers are reached, the tape is halted on the reel,
between the two end-of-tape markers.
Only the superuser can issue this command.  The command remains
in effect for the device until end-of-tape detection is disabled
with the \fBeotdis\fR command.
This is the default mode after a system boot.
.IP \fBfsf\fR
.NXR "fsf command (mt)"
Forward-space \fIcount\fR files.
.IP \fBfsr\fR
.NXR "fsr command (mt)"
Forward-space \fIcount\fR records.
.IP \fBnocache\fR
.NXR "nocache command (mt)"
Disables the use of the cache buffer for any 
tape drive that has the cache buffer feature.
.IP "\fBoffline, rewoffl\fR"
.NXR "offline command (mt)"
.NXR "rewolffl command (mt)"
Rewind the tape and place the tape unit off-line.
.IP \fBretension\fR
.NXR "retension command (mt)"
Retensions the tape.  Retension means moving the tape one complete
pass between EOT and BOT.
.IP \fBrewind\fR
.NXR "rewind command (mt)"
Rewind the tape.
.IP \fBstatus\fR
.NXR "status command (mt)"
Print status information about the tape unit.
.SH Examples
.NXR(e) "mt program" 
This example shows how to rewind the tape 
.PN rmt0l :
.EX
mt \-f /dev/rmt0l rewind
.EE
This example shows how to backspace the tape nmt1h 
three files:
.EX
mt \-f /dev/nrmt1h bsf 3
.EE
This example shows how to write two end-of-file marks at the
current position on tape nmt6h:
.EX
mt \-f /dev/nrmt6h eof 2
.EE
.SH Return Values
In shell scripts,
.PN 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 Files
.IP "/dev/rmt?h or /dev/rmt?l" 1i
Raw magnetic tape interface with rewind when closed
.IP "/dev/nmt?h or /dev/nmt?l" 1i
Raw magnetic tape interface with no rewind when closed
.SH See Also
dd(1), tar(1), ioctl(2), mtio(4), tms(4), environ(7)