.TH MT 1.SH NAMEmt \- magnetic tape control.SH SYNOPSIS.B mt.RB [ \-f.IR device ].RI [ count ].SH DESCRIPTION.B Mtis a user interface to the magnetic tape commands described in.BR mtio (4).It allows one to space a tape forwards or backwards, write end of filemarkers, etc..PPWith the.B \-foption a tape device can be named, otherwise the environment variable.B TAPEis used if set.  Standard input is used if the tape name is a dash (\-).  The.I countargument is used to tell how many blocks or files to space or how many filemarkers to write.  It may be a C-style decimal, octal or hexadecimal constant,by default "1"..PP.I Commandis the action to perform, it may be one of the following, or anyunambiguous prefix (like.B stfor.BR status ):.TP 15.B eof, weofWrite.I countend-of-file markers..TP.B fsfForward space.I countfile markers..TP.B fsrForward space.I countrecords.  (The size of a record depends on the tape, and may even bevariable, depending on the size of the writes.).TP.B bsfBackwards space.I countfiles.  The count may be zero to backspace to the start of the current file.(A tape device need not support backwards movement, or may be very slowdoing it.  Rewinding and forward spacing may be better.).TP.B bsrBackwards space.I countrecords.  The tape is positioned after the last block of the previous fileif you hit a filemark when spacing backwards.  The block count is set to -1to indicate that the driver has no idea where it is on the previous file..TP.B eomForward space to the end of media..TP.B rewindRewind the tape..TP.B offline, rewofflRewind and take offline.  This may cause some drives to eject the tape..TP.B statusShows the status of the drive, the sense key of the last SCSI error,current file number, current record number, residual count if the lastcommand that encountered end-of-file, and the current block size..TP.B retensionRemoves tape tension by winding and rewinding the tape completely..TP.B eraseErases the tape completely and rewinds it..TP.B densitySets the density code to read or write the tape to.IR count .Density codes supported depend on the drive.  This command need not beused if the drive senses the proper density on read and can only writeone density..TP.B blksize, blocksizeSets the block size used to read or write the tape to.IR count .This command may be used to select a fixed block size for a variable blocksize tape.  This will speed up I/O for small block sizes.  Use a zero.I countto use variable sized blocks again..SH ENVIRONMENT.TP 15n.B TAPETape drive to use if set..SH FILES.TP 15n.B /dev/nrst4Default tape device..SH "SEE ALSO".BR mtio (4),.BR st (4)..SH AUTHORKees J. Bot (kjb@cs.vu.nl)