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man pages section 1: User Commands

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Updated: Thursday, March 14, 2019
 
 

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

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Availability
system/core-os

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.