| Odevice\nflags\n | Arguments |
| device | The name of the device to open. |
| flags | 576 64|512 CREAT|TRUNC |
| C[device]\n | Close the currently open device. |
| Arguments | Any arguments are silently ignored. |
| Reply | A0\n on success. |
| whence | 0, SET, SEEK_SET seek from the file beginning 1, CUR, SEEK_CUR seek from the current location 2, END, SEEK_END seek from the file end |
| Reply | Aoffset\n on success. The offset is the new offset in file. |
| Extensions | BSD version allows only 0,1,2 as whence. |
| Rcount\n | Read count bytes of data from the current device. |
| count | number of bytes to read. |
| Reply | Ardcount\n followed by rdcount bytes of data read from the device. |
| Wcount\n | Writes data onto the current device. The command is followed by count bytes of input data. |
| count | Number of bytes to write. |
| Reply | On success: Awrcount\n, where wrcount is the number of bytes actually written. |
| Iopcode\ncount\n | Perform a MTIOCOPioctl(2) command with the specified paramedters. |
| opcode | MTIOCOP operation code. |
| count | mt_count. |
| Reply | On success: A0\n. |
| S\n | Returns the status of the currently open device, as obtained from a MTIOCGETioctl(2) call. |
| Arguments | None |
| Reply | On success: Acount\n followed by count bytes of data. |
NAME
rmt - remote magnetic tape server
SYNOPSIS
rmt
DESCRIPTION
Rmt provides remote access to files and devices for tar(1), cpio(1), and similar backup utilities. It is normally called by running rsh(1) or ssh(1) to the remote machine, optionally using a different login name if one is supplied.
The calling program communicates with rmt by sending requests on its standard input and reading replies from the standard output. A request consists of a request letter followed by an argument (if required) and a newline character. Additional data, if any, are sent after the newline. On success, rmt returns
Anumber\n
where number is an ASCII representation of a decimal return code. Additional data are returned after this line. On error, the following response is returned:
Eerrno\nerror-message\n
where errno is one of the system error codes, as described in errno(3), and error-message is a one-line human-readable description of the error, as printed by perror(3).
Available commands and possible responses are discussed in detail in the subsequent section.
COMMANDS
- Odevice\nflags\n
Arguments
- device
The name of the device to open.
- flags
- bash
576 64|512 CREAT|TRUNC
Reply
Extensions
- C[device]\n
Close the currently open device.
- Arguments
Any arguments are silently ignored.
- Reply
A0\n on success.
- Lwhence\noffset\n
- Arguments
- whence
- bash
0, SET, SEEK_SET seek from the file beginning 1, CUR, SEEK_CUR seek from the current location 2, END, SEEK_END seek from the file end
- Reply
Aoffset\n on success. The offset is the new offset in file.
- Extensions
BSD version allows only 0,1,2 as whence.
- Rcount\n
Read count bytes of data from the current device.
- Arguments
- count
number of bytes to read.
- Reply
Ardcount\n
followed by rdcount bytes of data read from the device.
- Wcount\n
Writes data onto the current device. The command is followed by count bytes of input data.
- Arguments
- count
Number of bytes to write.
- Reply
On success: Awrcount\n, where wrcount is the number of bytes actually written.
- Iopcode\ncount\n
Perform a MTIOCOPioctl(2) command with the specified paramedters.
- Arguments
- opcode
MTIOCOP operation code.
- count
mt_count.
- Reply
On success: A0\n.
- S\n
Returns the status of the currently open device, as obtained from a MTIOCGETioctl(2) call.
- Arguments
None
- Reply
On success: Acount\n followed by count bytes of data.
SEE ALSO
tar(1).
BUGS
Using this utility as a general-purpose remote file access tool is discouraged.
BUG REPORTS
Report bugs to <[email protected]>.
HISTORY
The rmt command appeared in 4.2BSD. The GNU rmt is written from scratch, using the BSD specification.
COPYRIGHT
Copyright © 2013, 2018 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.