MT(1) User Commands MT(1)

NAME

mt - magnetic tape control

SYNOPSIS

mt [-f tapename] command... [count]

DESCRIPTION

The mt utility sends commands to a magnetic tape drive. If -f tapename is
not specified, the environment variable TAPE is used. If TAPE does not
exist, mt uses the device /dev/rmt/0n.

OPTIONS

The following options are supported:

-f tapename
Specifies the raw tape device.

OPERANDS

The following operands are supported:

count
The number of times that the requested operation is to be
performed. By default, mt performs command once. Multiple
operations of command can be performed by specifying count.


command
The following available commands that can be sent to a
magnetic tape drive are supported. Only as many characters as
are required to uniquely identify a command need be specified.

asf
Specifies absolute space to count file number. This
is equivalent to a rewind followed by a fsf count.


bsf
Back spaces over count EOF marks. The tape is
positioned on the beginning-of-tape side of the EOF
mark.


bsr
Back spaces count records.


bssf
Back spaces over the requested number of sequential
file marks. Sequential file marks are where the file
marks are one right after the other with no other
blocks of any kind between the file marks. The
number argument specifies how many sequential file
marks to which to space. For example, bssf 4
searches backwards to the first place where there
are 4 sequential file marks and positions to the BOP
side of the 4th file mark.

This command is not supported by all drives.


eof
weof
Writes count EOF marks at the current position on
the tape.


fsf
Forward spaces over count EOF marks. The tape is
positioned on the first block of the file.


fsr
Forward spaces count records.


fssf
Forward spaces the over requested number of
sequential file marks. Sequential file marks are
where the file marks are one right after the other
with no other blocks of any kind between the file
marks. The number argument specifies how many
sequential file marks to which to space. For
example, fssf 4 searches forwards to the first place
where there are 4 sequential file marks and
positions after the 4th file mark.

This command is not supported by all drives.


load
Requests drive load and thread current media. Not
supported by all drives.


lock
Prevents media removal.


nbsf
Back spaces count files. The tape is positioned on
the first block of the file. This is equivalent to
count+1 bsfs followed by one fsf.


seek
Positions to requested logical tape position.


tell
Gets and prints current logical tape position.


unlock
Allows media removal.

If count is specified with any of the following commands, the
count is ignored and the command is performed only once.

config
Reads the drives current configuration from
the driver and displays it in st.conf format.
See st(4D) for definition of fields and there
meanings.


eom
Spaces to the end of recorded media on the
tape. This is useful for appending files onto
previously written tapes.


erase
Erases the entire tape.

Some tape drives have option settings where
only portions of the tape can be erased. Be
sure to select the correct setting to erase
the whole tape. Erasing a tape can take a long
time depending on the device and/or tape.
Refer to the device specific manual for time
details.


forcereserve
Attempts to break a SCSI II reserve issued by
another initiator. When this command
completes, the drive is not reserved for the
current initiator, but is available for use.
This command can be only be executed by those
with super-user privileges.


offline
rewoffl
Rewinds the tape and, if appropriate, takes
the drive unit off-line by unloading the tape.


release
Re-establishes the default behavior of
releasing at close.


reserve
Allows the tape drive to remain reserved after
closing the device. The drive must then be
explicitly released.


retension
Rewinds the cartridge tape completely, then
winds it forward to the end of the reel and
back to beginning-of-tape to smooth out tape
tension.


rewind
Rewinds the tape.


status
Prints status information about the tape unit.

Status information can include the sense key
reported by the drive, the residual and
retries for the last operation, the current
tape position reported in file number, and the
number of blocks from the beginning of that
file. It might also report that WORM media is
loaded in that drive.

EXIT STATUS

0
All operations were successful.


1
Command was unrecognized or mt was unable to open the specified tape
drive.


2
An operation failed.

FILES

/dev/rmt/*
magnetic tape interface

SEE ALSO

tar(1), tcopy(1), ar.h(3HEAD), st(4D), mtio(4I), attributes(7)

BUGS

Not all devices support all options. Some options are hardware-dependent.
Refer to the corresponding device manual page.


mt is architecture sensitive. Heterogeneous operation (that is, SPARC to
x86 or the reverse) is not supported.

June 21, 2007 MT(1)