TAR(1) BSD General Commands Manual TAR(1)
gnutar -- tape archiver; manipulate "tar" archive files
gnutar [[-]bundled-options Args] [gnu-style-flags] [filenames | -C directory-name] ...
Tar is short for ``tape archiver'', so named for historical reasons; the gnutar program cre-
ates, adds files to, or extracts files from an archive file in gnutar format, called a
tarfile. A tarfile is often a magnetic tape, but can be a floppy diskette or any regular
The first argument word of the gnutar 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 sec-
tion). Functions and function modifiers can also be specified with the GNU argument conven-
tion (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.
Exactly one of the following functions must be specified.
--concatenate Append the contents of named file, which must itself be a gnutar 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 tapes.
--create Create a new archive (or truncates an old one) and writes the named files to
--compare Find differences between files in the archive and corresponding files in the
--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
--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-
--get Extract files from an archive. The owner, modification time, and file per-
missions 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 versions.
The other options to gnutar may be combined arbitrarily; single-letter options may be bun-
dled 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). gnutar will properly handle option arguments passed either with or without
a leading `=` (i.e. either --option=arg or --option arg).
--help Prints a message listing and briefly describing all the command
options to gnutar.
--atime-preserve Restore the access times on files which are written to tape (note
that this will change the inode-change time!).
--record-size size Sets the block size for reading or writing to number * 512-byte
blocks. Or sets block size for reading or writing to size bytes
which must be a multiple of 512.
--read-full-records Re-assemble short reads into full records (for reading 4.2BSD
--backup control Backup files before removal. Optionally, the user can specify a
control argument to control how gnutar performs the backups. Sup-
ported values are listed bellow in the ENVIRONMENT section.
--suffix suffix Backup files before removal. Override the normal backup suffix
(default: '~'), using suffix instead.
--directory directory Change to directory before processing the remaining arguments.
--checkpoint Print number of buffer reads/writes while reading/writing the ar-
--file [hostname:]file Read or write the specified file (default is /dev/sa0). If a
hostname is specified, gnutar will use rmt(8) to read or write the
specified file on a remote machine. ``-'' may be used as a file-
name, for reading or writing to/from stdin/stdout.
--force-local Archive file is local even if it has a colon.
Run a script at the end of each archive volume (implies -M).
--incremental Create/list/extract old GNU-format incremental backup.
Create/list/extract new GNU-format incremental backup.
--group name Force group as group for added files.
--dereference Don't write symlinks as symlinks; write the data of the files they
--ignore-zeros Ignore blocks of zeroes in archive (usually means End-Of-File).
--ignore-failed-read Don't exit with non-zero status on unreadable files.
--bzip2 Filter the archive through bzip2(1).
--keep-old-files Keep files which already exist on disk; don't overwrite them from
--starting-file file Begin at file in the archive.
--one-file-system Stay in local file system when creating an archive (do not cross
--tape-length number Change tapes after writing number * 1024 bytes.
--mode changes Force changes to file mode of added files.
--modification-time Don't extract file modified time.
--multi-volume Create/list/extract multi-volume archive.
--no-recursion Don't recurse into subdirectories when creating.
--volno-file file File name with volume number to start with.
--newer date Only store files with creation time newer than date.
--newer-mtime date Only store files with modification time newer than date.
--no-same-owner Do not preserve ownership when extracting files. Extract them all
as owned by the current user.
--no-same-permissions Do not extract permission information. Extract them using the
default permissions for the current user.
--numeric-owner Use numbers instead of names for owner/group names.
--portability Write a V7 format archive, rather than POSIX format.
--to-stdout Extract files to standard output.
--owner name Force name as owner for added files.
--overwrite Overwrite existing files when extracting.
--overwrite-dir Overwrite directory metadata when extracting.
--preserve-permissions Extract all permission information.
--preserve Has the effect of -p -s.
--absolute-names Don't strip leading '/' from file names.
--posix Instructs gnutar to create a POSIX compliant `tar' archive.
--block-number Show record number within archive with each message.
--remove-files Remove files after adding them to the archive.
--rsh-command command Use command instead of rsh for remote archives/files.
--preserve-order List of names to extract is sorted to match archive.
--same-owner Try to preserve ownership when extracting files.
--show-omitted-dirs Show directories which were omitted while processing the archive.
--sparse Handle ``sparse'' files efficiently.
--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
--totals Prints total bytes written with --create.
--unlink-first Unlink files before creating them.
--recursive-unlink Empty hierarchies prior to extracting directory.
--verbose Lists files written to archive with --create or extracted with
--extract; lists file protection information along with file names
--label volume-name Create archive with the given volume-name. When used with list or
extract, volume-name is used as a globing pattern.
--version Print gnutar 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).
--exclude-from file Exclude files listed in file.
--anchored Exclude patterns match file name start (default).
--no-anchored Exclude patterns match after any /.
--ignore-case Exclude patterns ignore case.
--no-ignore-case Exclude patterns are case sensitive (default).
--wildcards Exclude patterns use wildcards (default).
--no-wildcards Exclude patterns are plain strings.
Exclude pattern wildcards match '/' (default).
Exclude pattern wildcards do not match '/'.
--uncompress Filter the archive through compress(1).
--gunzip Filter the archive through gzip(1).
Filter the archive through program (which must accept -d to mean
-[0-7][lmh] Specify tape drive and density.
The gnutar program examines the following environment variables.
POSIXLY_CORRECT Normally, gnutar will process flag arguments that appear in the file list.
If set in the environment, this causes gnutar 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.
Sets the backup suffix used by gnutar. Default is '~'.
TAPE Changes gnutar's default tape drive (which is still overridden by the -f
TAR_OPTIONS The environment variable TAR_OPTIONS can hold a set of default options for
gnutar. These options are interpreted first and can be overwritten by
explicit command line parameters.
TAR_RSH The TAR_RSH environment variable allows you to override the default shell
used as the transport for gnutar.
VERSION_CONTROL Sets the backup method used by gnutar. Possible values:
make numbered backups
numbered if numbered backups exist, simple otherwise
always make simple backups
Default behaviour is 'existing'.
/dev/sa0 The default tape drive.
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 course).
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 command-line like
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 gnutar 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 gnutar 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'.
bzip2(1), compress(1), gzip(1), pax(1), rmt(8), info tar
The gnutar format has a rich history, dating back to Sixth Edition UNIX. The current imple-
mentation of gnutar is the GNU implementation, which originated as the public-domain gnutar
written by John Gilmore.
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.
The -C feature does not work like historical gnutar programs, and is probably untrustworthy.
The -A command should work to join an arbitrary number of gnutar archives together, but it
does not; attempting to do so leaves the end-of-archive blocks in place for the second and
The gnutar 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 can not absorb our 32 bit (8 major, 16+8
BSD December 23, 2000 BSD