man pages section 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 option is 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 may be performed by specifying count.

command

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

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.
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.
nbsf: Back spaces count files. The tape is positioned on the first block of the file. This is equivalent to count+1 bsf's followed by one fsf.
asf: Specifies absolute space to count file number. This is equivalent to a rewind followed by a fsf count.

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

eom: Spaces to the end of recorded media on the tape. This is useful for appending files onto previously written tapes.
rewind: Rewinds the tape.
offline rewoffl: Rewinds the tape and, if appropriate, takes the drive unit off-line by unloading the tape.
status: Prints status information about the tape unit.
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.
reserve: Allows the tape drive to remain reserved after closing the device. The drive must then be explicitly released.
release: Re-establishes the default behavior of releasing at close.
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.
erase: Erases the entire tape. Caution: Some tape drives have option settings where only portions of the tape may be erased. Be sure to select the correct setting to erase the whole tape. Erasing a tape may take a long time depending on the device and/or tape. Refer to the device specific manual for time details.
config: Reads the drives current configuration from the driver and displays it in st.conf format. See st(7D) for definition of fields and there meanings.

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(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Availability	SUNWcsu

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.

SunOS 5.10 Last Revised 21 Aug 2007