.TH TAR 1 .SH NAMEtar  \-  tape archiver.SH SYNOPSIS.B tar[ key ] [ name ... ].SH DESCRIPTION.I Tarsaves and restores fileson magtape.Its actions are controlled by the.I keyargument.The.I keyis a string of characters containingat most one function letter and possiblyone or more function modifiers.Other arguments to the command are file or directorynames specifying which files are to be dumped or restored.In all cases, appearance of a directory name refers tothe files and (recursively) subdirectories of that directory..PPThe function portion ofthe key is specified by one of the following letters:.TP 8.B  rThe named filesare writtenon the end of the tape.The.B cfunction implies this..TP 8.B  xThe named files are extracted from the tape.If the named file matches a directory whose contents had been written onto the tape, this directory is (recursively) extracted.The owner, modification time, and mode are restored (if possible).If no file argument is given, the entire content of thetape is extracted.Note that if multiple entries specifying the same fileare on the tape, the last one overwritesall earlier..TP 8.B  tThe names of the specified files are listed each time they occuron the tape.If no file argument is given,all of the names on the tape are listed..TP 8.B  uThe named files are added to the tape if either theyare not already there or havebeen modified since last put on the tape..TP 8.B  cCreate a new tape; writing begins on the beginningof the tape instead of after the last file.This command implies.B r..PPThe following characters may be used in addition to the letterwhich selects the function desired..TP 10.B  0,...,7Thismodifier selects the drive on which the tape is mounted.The default is.BR 1 ..TP 10.B  vNormally.I tardoes its work silently.The.B v(verbose)option causes it to type the name of each file it treatspreceded by the function letter.With the.B tfunction,.B vgives more information about thetape entries than just the name..TP 10.B  wcauses.I tarto print the action to be taken followed by file name, thenwait for user confirmation. If a word beginning with `y'is given, the action is performed. Any other input meansdon't do it..TP 10.B fcauses .I tarto use the next argument as the name of the archive insteadof /dev/mt?. If the name of the file is `\-', tar writes tostandard output or reads from standard input, whichever isappropriate. Thus,.I tarcan be used as the head or tail of a filter chain.I Tarcan also be used to move hierarchies with the command.ce 1cd fromdir; tar cf - . | (cd todir; tar xf -).TP 10.B bcauses.I tarto use the next argument as the blocking factor for taperecords. The default is 1, the maximum is 20. This optionshould only be used with raw magnetic tape archives (See.B fabove).The block size is determined automatically when readingtapes (key letters `x' and `t')..TP 10.B ltells.I tarto complain if it cannot resolve all of the linksto the files dumped. If this is not specified, noerror messages are printed..TP 10.B mtells.I tarto not restore the modification times.The mod timewill be the time of extraction..PP.SH FILES/dev/mt?.br/tmp/tar*.SH DIAGNOSTICSComplaints about bad key characters and tape read/write errors..brComplaints if enough memory is not available to holdthe link tables..SH BUGSThere is no way to ask for the.IR n -thoccurrence of a file..brTape errors are handled ungracefully..brThe.B uoption can be slow..brThe.B boption should not be used with archives that aregoing to be updated. The current magtape driver cannotbackspace raw magtape.If the archive is on a disk file the .B boption should not be used at all, as updatingan archive stored in this manner can destroy it..brThe current limit on file name length is100 characters.