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NAME    [Toc]    [Back]

     tar -- tape archiver; manipulate "tar" archive files

SYNOPSIS    [Toc]    [Back]

     tar [[-]bundled-options Args] [gnu-style-flags]
	 [filenames | -C directory-name] ...

DESCRIPTION    [Toc]    [Back]

     Tar is short for ``tape archiver'', so named for historical reasons; the
     tar program creates, adds files to, or extracts files from an archive
     file in tar format, called a tarfile.  A tarfile is often a magnetic
     tape, but can be a floppy diskette or any regular disk file.

     The first argument word of the tar command line is usually a command word
     of bundled function and modifier letters, optionally preceded by a dash;
     it must contain exactly one function letter from the set A, c, d, r, t,
     u, x, for append, create, difference, replace, table of contents, update,
     and extract (further described below).  The command word can also contain
     other function modifiers described below, some of which will take arguments
 from the command line in the order they are specified in the command
 word (review the EXAMPLES section).  Functions and function modifiers
 can also be specified with the GNU argument convention (preceded by
     two dashes, one function or modifier per word.  Command-line arguments
     that specify files to add to, extract from, or list from an archive may
     be given as shell pattern matching strings.

FUNCTIONS    [Toc]    [Back]

     Exactly one of the following functions must be specified.

     --concatenate  Append the contents of named file, which must itself be a
		    tar archive, to the end of the archive (erasing the old
		    end-of-archive block).  This has the effect of adding the
		    files contained in the named file to the first archive,
		    rather than adding the second archive as an element of the
		    first.  Note: This option requires a rewritable tarfile,
		    and therefore does not work on quarter-inch cartridge
     --create	    Create a new archive (or truncates an old one) and writes
		    the named files to it.
     --compare	    Find differences between files in the archive and corresponding
 files in the file system.
     --delete	    Delete named files from the archive.  (Does not work on
		    quarter-inch tapes).
     --append	    Append files to the end of an archive.  (Does not work on
		    quarter-inch tapes).
     --list	    List the contents of an archive; if filename arguments are
		    given, only those files are listed, otherwise the entire
		    table of contents is listed.
     --update	    Append the named files if the on-disk version has a modification
 date more recent than their copy in the archive
		    (if any).  Does not work on quarter-inch tapes.
     --get	    Extract files from an archive.  The owner, modification
		    time, and file permissions are restored, if possible.  If
		    no file arguments are given, extract all the files in the
		    archive.  If a filename argument matches the name of a
		    directory on the tape, that directory and its contents are
		    extracted (as well as all directories under that directory).
  If the archive contains multiple entries corresponding
 to the same file (see the --append command
		    above), the last one extracted will overwrite all earlier

OPTIONS    [Toc]    [Back]

     The other options to tar may be combined arbitrarily; single-letter
     options may be bundled in with the command word.  Verbose options which
     take arguments will be followed by the argument; single-letter options
     will consume successive command line arguments (see the EXAMPLES below).

     --help		     Prints a message listing and briefly describing
			     all the command options to tar.
     --atime-preserve	     Restore the access times on files which are written
 to tape (note that this will change the
			     inode-change time!).
     --block-size number     Sets the block size for reading or writing to
			     number * 512-byte blocks.
     --read-full-blocks      Re-assemble short reads into full blocks (for
			     reading 4.2BSD pipes).
     -C directory
     --directory directory   Change to directory before processing the remaining
     --checkpoint	     Print number of buffer reads/writes while reading/writing
 the archive.
     -f [hostname:]file
     --file [hostname:]file  Read or write the specified file (default is
			     /dev/sa0).  If a hostname is specified, tar will
			     use rmt(8) to read or write the specified file on
			     a remote machine.	``-'' may be used as a filename,
 for reading or writing to/from stdin/stdout.

     --force-local	     Archive file is local even if it has a colon.
     -F file
     --info-script file
     --new-volume-script file
			     Run a script at the end of each archive volume
			     (implies -M).
     --fast-read	     Stop after all non-wildcard extraction targets
			     have been found in the archive.
     --incremental	     Create/list/extract old GNU-format incremental
     -g file
     --listed-incremental file
			     Create/list/extract new GNU-format incremental
     --dereference	     Don't write symlinks as symlinks; write the data
			     of the files they name.
     --ignore-zeros	     Ignore blocks of zeroes in archive (usually means
     --ignore-failed-read    Don't exit with non-zero status on unreadable
     --bunzip2		     Filter the archive through bzip2(1).
     --keep-old-files	     Keep files which already exist on disk; don't
			     overwrite them from the archive.
     -K file
     --starting-file file    Begin at file in the archive.
     --one-file-system	     Stay in local file system when creating an archive
 (do not cross mount points).
     -L number
     --tape-length number    Change tapes after writing number * 1024 bytes.
     --modification-time     Don't extract file modified time.
     --multi-volume	     Create/list/extract multi-volume archive.
     --norecurse	     Don't recurse into subdirectories when creating.
     --volno-file file	     File name with volume number to start with.
     -N date
     --after-date date
     --newer date	     Only store files with creation time newer than
     --newer-mtime date      Only store files with modification time newer
			     than date.
     --portability	     Write a V7 format archive, rather than POSIX format.

     --to-stdout	     Extract files to standard output.
     --preserve-permissions  Extract all protection information.
     --preserve 	     Has the effect of -p -s.
     --absolute-paths	     Don't strip leading `/' from file names.
     --record-number	     Show record number within archive with each message.

     --remove-files	     Remove files after adding them to the archive.
     --preserve-order	     List of names to extract is sorted to match archive.

     --show-omitted-dirs     Show directories which were omitted while processing
 the archive.
     --sparse		     Handle ``sparse'' files efficiently.
     -T file
     -I file
     --files-from file	     Get names of files to extract or create from
			     file, one per line.
     --null		     Modifies behavior of -T to expect null-terminated
			     names; disables -C.
     --totals		     Prints total bytes written with --create.
     --unlink-first	     Unlink files before creating them.
     --verbose		     Lists files written to archive with --create or
			     extracted with --extract; lists file protection
			     information along with file names with --list.
     -V volume-name
     --label volume-name     Create archive with the given volume-name.
     --version		     Print tar program version number.
     --confirmation	     Ask for confirmation for every action.
     --verify		     Attempt to verify the archive after writing it.
     --exclude pattern	     Exclude files matching the pattern (don't extract
			     them, don't add them, don't list them).
     -X file
     --exclude-from file     Exclude files listed in file.
     --uncompress	     Filter the archive through compress(1).
     --gunzip		     Filter the archive through gzip(1).
     --use-compress-program program
			     Filter the archive through program (which must
			     accept -d to mean ``decompress'').
     --block-compress	     Block the output of compression program for tapes
			     or floppies (otherwise writes will be of odd
			     length, which device drivers may reject).
     -[0-7][lmh]	     Specify tape drive and density.

ENVIRONMENT    [Toc]    [Back]

     The environment variable TAR_OPTIONS can hold a set of default options
     for tar.  These options are interpreted first and can be overwritten by
     explicit command line parameters.

EXAMPLES    [Toc]    [Back]

     To create an archive on tape drive /dev/sa0 with a block size of 20
     blocks, containing files named bert and ernie, you can enter
	   tar cfb /dev/sa0 20 bert ernie
	   tar --create --file /dev/sa0 --block-size 20 bert ernie
     Note that the -f and -b flags both require arguments, which they take
     from the command line in the order they were listed in the command word.

     Because /dev/sa0 is the default device, and 20 is the default block size,
     the above example could have simply been
	   tar c bert ernie

     To extract all the C sources and headers from an archive named
     backup.tar, type
	   tar xf backup.tar '*.[ch]'
     Note that the pattern must be quoted to prevent the shell from attempting
     to expand it according the files in the current working directory (the
     shell does not have access to the list of files in the archive, of

     To move file hierarchies, use a command line like this:

     tar -cf - -C srcdir . | tar xpf - -C destdir

     To create a compressed archive on diskette, using gzip(1), use a commandline
	   tar --block-compress -z -c -v -f /dev/fd1a -b 36 tar/

     Note that you cannot mix bundled flags and --style flags; you can use
     single-letter flags in the manner above, rather than having to type
	   tar --block-compress --gzip --verbose --file /dev/fd1a --block-size
	   20 tar/

     The above-created diskette can be listed with
	   tar tvfbz /dev/fd1a 36

     To join two tar archives into a single archive, use
	   tar Af archive1.tar archive2.tar
     which will add the files contained in archive2.tar onto the end of
     archive1.tar (note that this can't be done by simply typing
	   cat archive2.tar >> archive1.tar
     because of the end-of-file block at the end of a tar archive).

     To archive all files from the directory srcdir, which were modified after
     Feb. 9th 1997, 13:00 h, use
	   tar -c -f backup.tar --newer-mtime 'Feb 9 13:15 1997' srcdir/

     Other possible time specifications are `02/09/97 13:15', `1997-02-09
     13:15', `13:15 9 Feb 1997', `9 Feb 1997 13:15', `Feb. 9, 1997 1:15pm',
     `09-Feb', `3 weeks ago' or `May first Sunday'.  To specify the correct
     time zone use either e.g. `13:15 CEST' or `13:15+200'.

ENVIRONMENT    [Toc]    [Back]

     The tar program examines the following environment variables.

     POSIXLY_CORRECT  Normally, tar will process flag arguments that appear in
		      the file list.  If set in the environment, this causes
		      tar to consider the first non-flag argument to terminate
		      flag processing, as per the POSIX specification.

     SHELL	      In interactive mode, a permissible response to the
		      prompt is to request to spawn a subshell, which will be
		      /bin/sh unless the SHELL variable is set.

     TAPE	      Changes tar's default tape drive (which is still overridden
 by the -f flag).

     TAR_RSH	      The TAR_RSH environment variable allows you to override
		      the default shell used as the transport for tar.

FILES    [Toc]    [Back]

     /dev/sa0  The default tape drive.

COMPATIBILITY    [Toc]    [Back]

     The -y is a FreeBSD localism.  The GNU tar maintainer has now chosen -j
     as the offical bzip2(1) compression option in GNU tar 1.13.18 and later.
     The -I option is for compatibility with Solaris's tar.

SEE ALSO    [Toc]    [Back]

     bzip2(1), compress(1), gzip(1), pax(1), rmt(8)

HISTORY    [Toc]    [Back]

     The tar format has a rich history, dating back to Sixth Edition UNIX.
     The current implementation of tar is the GNU implementation, which originated
 as the public-domain tar written by John Gilmore.

AUTHORS    [Toc]    [Back]

     A cast of thousands, including [as listed in the ChangeLog file in the
     source] John Gilmore (author of original public domain version), Jay
     Fenlason (first GNU author), Joy Kendall, Jim Kingdon, David J.
     MacKenzie, Michael I Bushnell, Noah Friedman, and innumerable others who
     have contributed fixes and additions.

     Man page obtained by the FreeBSD group from the NetBSD 1.0 release.

BUGS    [Toc]    [Back]

     The -C feature does not work like historical tar programs, and is probably

     The -A command should work to join an arbitrary number of tar archives
     together, but it does not; attempting to do so leaves the end-of-archive
     blocks in place for the second and subsequent archives.

     The tar file format is a semi fixed width field format, and the field for
     device numbers were designed for 16 bit (8 major, 8 minor) and cannot
     absorb our 32 bit (8 major, 16+8 minor) numbers.

FreeBSD 5.2.1		       December 23, 2000		 FreeBSD 5.2.1
[ Back ]
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