TAR(1)                     OpenBSD Reference Manual                     TAR(1)

NAME
     tar - tape archiver

SYNOPSIS
     tar [-]{crtux}[befhmopqsvwzHLOPXZ014578] [blocksize] [archive] [replstr]
         [-C directory] [-I file] [file ...]

DESCRIPTION
     The tar command creates, adds files to, or extracts files from an archive
     file in ``tar'' format.  A tar archive is often stored on a magnetic
     tape, but can be stored equally well on a floppy, CD-ROM, or in a regular
     disk file.

     One of the following flags must be present:

     -c            Create new archive, or overwrite an existing archive,
                   adding the specified files to it.

     -r            Append the named new files to existing archive.  Note that
                   this will only work on media on which an end-of-file mark
                   can be overwritten.

     -t            List contents of archive.  If any files are named on the
                   command line, only those files will be listed.

     -u            Alias for -r.

     -x            Extract files from archive.  If any files are named on the
                   command line, only those files will be extracted from the
                   archive.  If more than one copy of a file exists in the
                   archive, later copies will overwrite earlier copies during
                   extraction.  The file mode and modification time are pre-
                   served if possible.  The file mode is subject to modifica-
                   tion by the umask(2).

     In addition to the flags mentioned above, any of the following flags may
     be used:

     -b blocking factor
                   Set blocking factor to use for the archive.  tar uses 512
                   byte blocks.  The default is 20, the maximum is 126.
                   Archives with a blocking factor larger 63 violate the POSIX
                   standard and will not be portable to all systems.

     -e            Stop after first error.

     -f archive    Filename where the archive is stored.  Defaults to
                   /dev/rst0.

     -h            Follow symbolic links as if they were normal files or di-
                   rectories.

     -m            Do not preserve modification time.

     -O            Write old-style (non-POSIX) archives.

     -o            Don't write directory information that the older (V7) style
                   tar is unable to decode.  This implies the -O flag.

     -p            Preserve user and group ID as well as file mode regardless
                   of the current umask(2). The setuid and setgid bits are on-
                   ly preserved if the user is the superuser.  Only meaningful

                   in conjunction with the -x flag.

     -q            Select the first archive member that matches each pattern
                   operand.  No more than one archive member is matched for
                   each pattern. When members of type directory are matched,
                   the file hierarchy rooted at that directory is also
                   matched.

     -s replstr    Modify the file or archive member names specified by the
                   pattern or file operands according to the substitution ex-
                   pression replstr, using the syntax of the ed(1) utility
                   regular expressions.  The format of these regular expres-
                   sions are:
                         /old/new/[gp]
                   As in ed(1), old is a basic regular expression and new can
                   contain an ampersand (&), \n (where n is a digit) back-ref-
                   erences, or subexpression matching.  The old string may al-
                   so contain <newline> characters.  Any non-null character
                   can be used as a delimiter (/ is shown here).  Multiple -s
                   expressions can be specified.  The expressions are applied
                   in the order they are specified on the command line, termi-
                   nating with the first successful substitution.  The option-
                   al trailing g continues to apply the substitution expres-
                   sion to the pathname substring which starts with the first
                   character following the end of the last successful substi-
                   tution.  The first unsuccessful substitution stops the op-
                   eration of the g option.  The optional trailing p will
                   cause the final result of a successful substitution to be
                   written to standard error in the following format:
                         <original pathname> >> <new pathname>
                   File or archive member names that substitute to the empty
                   string are not selected and will be skipped.

     -v            Verbose operation mode.

     -w            Interactively rename files.  This option causes tar to
                   prompt the user for the filename to use when storing or ex-
                   tracting files in an archive.

     -z            Compress archive using gzip.

     -C directory  This is a positional argument which sets the working direc-
                   tory for the following files.  When extracting, files will
                   be extracted into the specified directory; when creating,
                   the specified files will be matched from the directory.

     -H            Follow symlinks given on command line only.

     -L            Follow all symlinks.

     -P            Do not strip leading slashes (`/') from pathnames.  The de-
                   fault is to strip leading slashes.

     -I file       This is a positional argument which reads the names of
                   files to archive or extract from the given file, one per
                   line.

     -X            Do not cross mount points in the file system.

     -Z            Compress archive using compress.

     The options [-014578] can be used to select one of the compiled-in backup
     devices, /dev/rstN.

DIAGNOSTICS

     tar will exit with one of the following values:

     0   All files were processed successfully.

     1   An error occurred.

     Whenever tar cannot create a file or a link when extracting an archive or
     cannot find a file while writing an archive, or cannot preserve the user
     ID, group ID, file mode, or access and modification times when the -p op-
     tion is specified, a diagnostic message is written to standard error and
     a non-zero exit value will be returned, but processing will continue.  In
     the case where tar cannot create a link to a file, tar will not create a
     second copy of the file.

     If the extraction of a file from an archive is prematurely terminated by
     a signal or error, tar may have only partially extracted the file the us-
     er wanted.  Additionally, the file modes of extracted files and directo-
     ries may have incorrect file bits, and the modification and access times
     may be wrong.

     If the creation of an archive is prematurely terminated by a signal or
     error, tar may have only partially created the archive which may violate
     the specific archive format specification.

FILES
     /dev/rst0  default archive name

ENVIRONMENT
     TMPDIR      Path in which to store temporary files.

     TAPE        Default tape device to use instead of /dev/rst0.

SEE ALSO
     cpio(1), pax(1)

AUTHORS
     Keith Muller at the University of California, San Diego.

HISTORY
     A tar command first appeared in Version 7 AT&T UNIX.

CAVEATS
     The -L flag is not portable to other versions of tar where it may have a
     different meaning.

OpenBSD 3.0                    February 7, 2001                              3
