1.\" $NetBSD: mt.1,v 1.38 2018/09/01 07:26:56 wiz Exp $ 2.\" 3.\" Copyright (c) 1981, 1990, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)mt.1 8.1 (Berkeley) 6/6/93 31.\" 32.Dd September 1, 2018 33.Dt MT 1 34.Os 35.Sh NAME 36.Nm mt 37.Nd magnetic tape manipulation 38.Sh SYNOPSIS 39.Nm 40.Op Fl f Ar tapename 41.Ar command 42.Op Ar count 43.Sh DESCRIPTION 44The 45.Nm 46program is used to give commands to a magnetic tape drive. 47By default 48.Nm 49performs the requested operation once. 50Operations may be performed multiple times by specifying 51.Ar count . 52.Pp 53Note 54that 55.Ar tapename 56must reference a raw (not block) tape device. 57If 58.Ar tapename 59is of the form 60.Qq host:tapename , 61or 62.Qq user@host:tapename , 63.Nm 64writes to the named tape device on the remote host using 65.Xr rmt 8 . 66.Pp 67The 68.Xr rmt 8 69process on the remote host is typically initiated via 70.Xr rsh 1 , 71although an alternate method such as 72.Xr ssh 1 73can be specified via the 74.Ev RCMD_CMD 75environment variable. 76.Pp 77The available commands are listed below. 78Only as many characters as are required to uniquely identify a command 79need be specified. 80.Bl -tag -width "eof, weof" 81.It Cm asf 82Move forward 83.Ar count 84files from the beginning of the tape. 85This is accomplished by a rewind followed by fsf 86.Ar count . 87.It Cm eof , weof 88Write 89.Ar count 90end-of-file marks at the current position on the tape. 91.It Cm fsf 92Forward space 93.Ar count 94files. 95.It Cm fsr 96Forward space 97.Ar count 98records. 99.It Cm bsf 100Back space 101.Ar count 102files. 103.It Cm bsr 104Back space 105.Ar count 106records. 107.It Cm rewind 108Rewind the tape. 109(The 110.Ar count 111is ignored.) 112.It Cm offline , rewoffl 113Rewind the tape and place the tape unit off-line. 114Where supported, this ejects the tape. 115(The 116.Ar count 117is ignored.) 118.It Cm status 119Print status information about the tape unit. 120(The 121.Ar count 122is ignored.) 123.It Cm retension 124Retensions the tape. 125Not all tape drives support this feature. 126(The 127.Ar count 128is ignored.) 129.It Cm erase 130Erases the tape 131Not all tape drives support this feature. 132(The 133.Ar count 134is ignored.) 135.It Cm eew 136Enable or disable early warning EOM behaviour. 137Set 138.Ar count 139to nonzero to enable, zero to disable. 140.It Cm eom 141Forward space to the end of recorded media. 142(The 143.Ar count 144is ignored.) 145.It Cm blocksize , setblk 146Set the tape blocksize to 147.Ar count 148bytes. 149A 150.Ar count 151of zero sets variable blocksize. 152.It Cm density , setdensity 153Set the tape density code to 154.Ar count 155as specified in the 156.Tn SCSI-3 157specification. 158See the 159.Sx DENSITY CODES 160section for a list of codes for commonly used media types. 161.It Cm rdspos 162Read the logical block position of the tape. 163Not all tape drives support this feature. 164(The 165.Ar count 166is ignored.) 167.It Cm rdhpos 168Read the hardware block position of the tape. 169Not all tape drives support this feature. 170(The 171.Ar count 172is ignored.) 173.It Cm setspos 174Set the logical block position of the tape to 175.Ar count . 176Not all tape drives support this feature. 177.It Cm sethpos 178Set the hardware block position of the tape to 179.Ar count . 180Not all tape drives support this feature. 181.It Cm compress 182If 183.Ar count 184is zero, disable compression. 185Otherwise enable compression. 186Not all tape drives support this feature. 187.It Cm cache 188Enable controller buffering. 189.It Cm nocache 190Disable controller buffering. 191.El 192.Pp 193If a tape name is not specified, and the environment variable 194.Ev TAPE 195is not set, then 196.Nm 197uses the device 198.Pa /dev/nrst0 . 199.Sh ENVIRONMENT 200If the following environment variables exist, they are used by 201.Nm . 202.Bl -tag -width Fl 203.It Ev TAPE 204.Nm 205uses device filename given in the 206.Ev TAPE 207environment variable if the 208.Ar tapename 209argument is not given. 210.It Ev RCMD_CMD 211.Nm 212will use 213.Ev RCMD_CMD 214rather than 215.Pa /usr/bin/rsh 216to invoke 217.Xr rmt 8 218on a remote machine. 219The full path name must be specified. 220.El 221.Sh FILES 222.Bl -tag -width /dev/rst* -compact 223.It Pa /dev/rst* 224Raw 225.Tn SCSI 226tape device 227.It Pa /dev/rmt* 228Raw magnetic tape device 229.El 230.Sh EXIT STATUS 231.Nm 232returns a 0 exit status when the operation(s) were successful, 2331 if the command was unrecognized, and 2 if an operation failed. 234.Sh DENSITY CODES 235The SCSI-3 specification defines a number of density codes for 236various tape media, some of which are listed here. 237Note that many tape drive vendors also define model-specific codes. 238.Pp 239.Bl -column "Code" "Format" -compact 240.It Em Code Ta Em Format 241.It Li 0 Ta Device default 242.It Li 1 Ta 1/2" 800 bpi 243.It Li 2 Ta 1/2" 1600 bpi 244.It Li 3 Ta 1/2" 6250 bpi 245.It Li 4 Ta QIC-11 246.It Li 5 Ta QIC-24 247.It Li 15 Ta QIC-120 248.It Li 16 Ta QIC-150 249.It Li 17 Ta QIC-320/525 250.It Li 18 Ta QIC-1320/1350 251.It Li 19 Ta DDS 252.It Li 28 Ta QIC-385M 253.It Li 29 Ta QIC-410M 254.It Li 30 Ta QIC-1000C 255.It Li 31 Ta QIC-2100C 256.It Li 32 Ta QIC-6GB 257.It Li 33 Ta QIC-20GB 258.It Li 34 Ta QIC-2GB 259.It Li 35 Ta QIC-875M 260.It Li 36 Ta DDS-2 261.It Li 37 Ta DDS-3 262.It Li 38 Ta DDS-4 263.El 264.Sh SEE ALSO 265.Xr dd 1 , 266.Xr ioctl 2 , 267.Xr mtio 4 , 268.Xr st 4 , 269.Xr environ 7 270.Sh HISTORY 271The 272.Nm 273utility appeared in 274.Bx 4.3 . 275