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TAR(1)                      General Commands Manual                     TAR(1)



NAME
       tar  -  tape archiver

SYNOPSIS
       tar [ key ] [ name ... ]

DESCRIPTION
       Tar saves and restores files on magtape.  Its actions are controlled by
       the key argument.  The key is a string of characters containing at most
       one function letter and possibly one or more function modifiers.  Other
       arguments to the command are file or directory names  specifying  which
       files  are  to  be  dumped  or restored.  In all cases, appearance of a
       directory name refers to the files and (recursively) subdirectories  of
       that directory.

       The  function  portion  of the key is specified by one of the following
       letters:

       r       The named files are written on the end  of  the  tape.   The  c
               function implies this.

       x       The 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 the tape is
               extracted.  Note that if multiple entries specifying  the  same
               file are on the tape, the last one overwrites all earlier.

       t       The  names  of  the  specified  files are listed each time they
               occur on the tape.  If no file argument is given,  all  of  the
               names on the tape are listed.

       u       The  named  files  are added to the tape if either they are not
               already there or have been modified since last put on the tape.

       c       Create a new tape; writing begins on the beginning of the  tape
               instead of after the last file.  This command implies r.

       The  following  characters  may be used in addition to the letter which
       selects the function desired.

       0,...,7   This modifier selects the drive on which the tape is mounted.
                 The default is 1.

       v         Normally  tar does its work silently.  The v (verbose) option
                 causes it to type the name of each file it treats preceded by
                 the  function  letter.   With  the  t  function, v gives more
                 information about the tape entries than just the name.

       w         causes tar to print the action to be taken followed  by  file
                 name,  then  wait  for user confirmation. If a word beginning
                 with `y' is given, the action is performed. Any  other  input
                 means don't do it.

       f         causes  tar  to  use the next argument as the name of the ar-
                 chive instead of /dev/mt?.  If the name of the file  is  `-',
                 tar  writes  to standard output or reads from standard input,
                 whichever is appropriate. Thus, tar can be used as  the  head
                 or  tail of a filter chain Tar can also be used to move hier-
                 archies with the command
                         cd fromdir; tar cf - . | (cd todir; tar xf -)

       b         causes tar to use the next argument as  the  blocking  factor
                 for  tape  records. The default is 1, the maximum is 20. This
                 option should only be used with raw  magnetic  tape  archives
                 (See  f  above).   The block size is determined automatically
                 when reading tapes (key letters `x' and `t').

       l         tells tar to complain if it cannot resolve all of  the  links
                 to  the files dumped. If this is not specified, no error mes-
                 sages are printed.

       m         tells tar to not restore the  modification  times.   The  mod
                 time will be the time of extraction.

FILES
       /dev/mt?
       /tmp/tar*

DIAGNOSTICS
       Complaints about bad key characters and tape read/write errors.
       Complaints if enough memory is not available to hold the link tables.

BUGS
       There is no way to ask for the n-th occurrence of a file.
       Tape errors are handled ungracefully.
       The u option can be slow.
       The  b  option  should  not  be used with archives that are going to be
       updated. The current magtape driver cannot backspace raw  magtape.   If
       the  archive  is on a disk file the b option should not be used at all,
       as updating an archive stored in this manner can destroy it.
       The current limit on file name length is 100 characters.



                                                                        TAR(1)