MT(1L)									MT(1L)



NAME
       mt - control magnetic tape drive operation

SYNOPSIS
       mt [-V] [-f device] [--file=device] [--rsh-command=command] [--version]
       operation [count]

DESCRIPTION
       This manual page documents the GNU version  of  mt.   mt  performs  the
       given operation, which must be one of the tape operations listed below,
       on a tape drive.

       The  default  tape  device  to  operate	on  is	taken  from  the  file
       /usr/include/sys/mtio.h	when  mt is compiled.  It can be overridden by
       giving a device file name in the environment variable TAPE or by a com
       mand  line  option  (see  below),  which also overrides the environment
       variable.

       The device must be either a character special file  or  a  remote  tape
       drive.	To  use  a tape drive on another machine as the archive, use a
       filename that starts with HOSTNAME:.  The hostname can be preceded by
       a  username and an @ to access the remote tape drive as that user, if
       you have permission to  do  so  (typically  an  entry  in  that	users
       ~/.rhosts file).

       The  available  operations  are listed below.  Unique abbreviations are
       accepted.  Not all operations are available on all systems, or work  on
       all  types  of  tape  drives.  Some operations optionally take a repeat
       count, which can be given after the operation name and defaults to 1.

       eof, weof
	      Write count EOF marks at current position.

       fsf    Forward space count files.  The tape is positioned on the  first
	      block of the next file.

       bsf    Backward space count files.  The tape is positioned on the first
	      block of the next file.

       fsr    Forward space count records.

       bsr    Backward space count records.

       bsfm   Backward space count file marks.	The tape is positioned on  the
	      beginning-of-the-tape side of the file mark.

       fsfm   Forward  space  count file marks.  The tape is positioned on the
	      beginning-of-the-tape side of the file mark.

       asf    Absolute space to file number count.  Equivalent to rewind  fol
	      lowed by fsf count.

       eom    Space  to the end of the recorded media on the tape (for append
	      ing files onto tapes).

       rewind Rewind the tape.

       offline, rewoffl
	      Rewind the tape and, if applicable, unload the tape.

       status Print status information about the tape unit.

       retension
	      Rewind the tape, then wind it to	the  end  of  the  reel,  then
	      rewind it again.

       erase  Erase the tape.

       fss    (SCSI tapes) Forward space count setmarks.

       bss    (SCSI tapes) Backward space count setmarks.

       wset   (SCSI tapes) Write count setmarks at current position (only SCSI
	      tape).

       eod, seod
	      Space to end of valid data.  Used on  streamer  tape  drives  to
	      append data to the logical and of tape.

       setblk (SCSI  tapes) Set the block size of the drive to count bytes per
	      record.

       setdensity
	      (SCSI tapes) Set the tape density code  to  count.   The	proper
	      codes  to use with each drive should be looked up from the drive
	      documentation.

       drvbuffer
	      (SCSI tapes) Set the tape drive  buffer  code  to  number.   The
	      proper  value  for  unbuffered  operation  is  zero and "normal"
	      buffered operation one. The meanings  of	other  values  can  be
	      found  in the drive documentation or, in case of a SCSI-2 drive,
	      from the SCSI-2 standard.

       stoptions
	      (SCSI tapes) Set the  driver  options  bits  to  count  for  the
	      device.  The bits can be set by oring the following values: 1 to
	      enable write buffering, 2 to enable asynchronous	writes,  4  to
	      enable  read ahead, 8 to enable debugging output (if it has been
	      compiled to the driver).

       stwrthreshold
	      (SCSI tapes) The write threshold for the tape device is  set  to
	      count  kilobytes. The value must be smaller than or equal to the
	      driver buffer size.

       seek   (SCSI tapes) Seek to the count block on the tape.   This	opera
	      tion  is	available  on  some Tandberg and Wangtek streamers and
	      some SCSI-2 tape drives.

       tell   (SCSI tapes) Tell the current block on tape.  This operation  is
	      available on some Tandberg and Wangtek streamers and some SCSI-2
	      tape drives.

       densities
	      (SCSI tapes) Write explanation of some common density  codes  to
	      standard output.

       datcompression
	      (some  SCSI-2  DAT  tapes) Inquire or set the compression status
	      (on/off). If the count is one the compression status is printed.
	      If  the  count is zero, compression is disabled. Otherwise, com
	      pression is enabled. The command uses the SCSI ioctl to read and
	      write  the Data Compression Characteristics mode page (15). ONLY
	      ROOT CAN USE THIS COMMAND.

       mt exits with a status of 0 if the operation succeeded, 1 if the opera
       tion or device name given was invalid, or 2 if the operation failed.

   OPTIONS
       -f, --file=device
	      Use device as the file name of the tape drive to operate on.  To
	      use a tape drive on another machine, use a filename that	starts
	      with  HOSTNAME:.	 The  hostname can be preceded by a username
	      and an @ to access the remote tape drive as that user, if  you
	      have  permission	to  do	so  (typically an entry in that users
	      ~/.rhosts file).

       --rsh-command=command
	      Notifies mt that it  should  use	command  to  communicate  with
	      remote  devices  instead	of  /usr/bin/ssh, /usr/bin/rsh, or the
	      command specified by the environment variable MT_RSH.

       -V, --version
	      Print the version number of mt.



									MT(1L)