TAR(1) BSD General Commands Manual TAR(1)NAMEgnutar — tape archiver; manipulate "tar" archive files
SYNOPSISgnutar [[-]bundled-options Args] [gnu-style-flags]
[filenames | -C directory-name] ...
DESCRIPTION
Tar is short for “tape archiver”, so named for historical reasons; the
gnutar program creates, 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 disk file.
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 section). Functions and function modi‐
fiers 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
Exactly one of the following functions must be specified.
-A
--catenate
--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.
-c
--create Create a new archive (or truncates an old one) and writes
the named files to it.
-d
--diff
--compare Find differences between files in the archive and corre‐
sponding files in the file system.
--delete Delete named files from the archive. (Does not work on
quarter-inch tapes).
-r
--append Append files to the end of an archive. (Does not work on
quarter-inch tapes).
-t
--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.
-u
--update Append the named files if the on-disk version has a modi‐
fication date more recent than their copy in the archive
(if any). Does not work on quarter-inch tapes.
-x
--extract
--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 direc‐
tory). If the archive contains multiple entries corre‐
sponding to the same file (see the --append command
above), the last one extracted will overwrite all earlier
versions.
OPTIONS
The other options to gnutar 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).
gnutar will properly handle option arguments passed either with or with‐
out 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 writ‐
ten to tape (note that this will change the
inode-change time!).
-b
--block-size number
--blocking-factor number
--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.
-B
--read-full-records Re-assemble short reads into full records (for
reading 4.2BSD pipes).
--backup control Backup files before removal. Optionally, the
user can specify a control argument to control
how gnutar performs the backups. Supported val‐
ues are listed bellow in the ENVIRONMENT section.
--suffix suffix Backup files before removal. Override the normal
backup suffix (default: '~'), using suffix
instead.
-C directory
--directory directory Change to directory before processing the remain‐
ing arguments.
--checkpoint Print number of buffer reads/writes while read‐
ing/writing the archive.
-f [hostname:]file
--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
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).
-G
--incremental Create/list/extract old GNU-format incremental
backup.
-g file
--listed-incremental file
Create/list/extract new GNU-format incremental
backup.
--group name Force group as group for added files.
-h
--dereference Don't write symlinks as symlinks; write the data
of the files they name.
-i
--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.
-j
--bzip2 Filter the archive through bzip2(1).
-k
--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.
-l
--one-file-system Stay in local file system when creating an ar‐
chive (do not cross mount points).
-L number
--tape-length number Change tapes after writing number * 1024 bytes.
--mode changes Force changes to file mode of added files.
-m
--modification-time Don't extract file modified time.
-M
--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.
-N date
--after-date date
--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 cur‐
rent user.
--numeric-owner Use numbers instead of names for owner/group
names.
-o
--old-archive
--portability Write a V7 format archive, rather than POSIX for‐
mat.
-O
--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.
-p
--same-permissions
--preserve-permissions Extract all permission information.
--preserve Has the effect of -p -s.
-P
--absolute-names Don't strip leading ‘/’ from file names.
--posix Instructs gnutar to create a POSIX compliant
`tar' archive.
-R
--block-number Show record number within archive with each mes‐
sage.
--remove-files Remove files after adding them to the archive.
--rsh-command command Use command instead of rsh for remote ar‐
chives/files.
-s
--same-order
--preserve-order List of names to extract is sorted to match ar‐
chive.
--same-owner Try to preserve ownership when extracting files.
--show-omitted-dirs Show directories which were omitted while pro‐
cessing the archive.
-S
--sparse Handle “sparse” files efficiently.
-T 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.
-U
--unlink-first Unlink files before creating them.
--recursive-unlink Empty hierarchies prior to extracting directory.
-v
--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. When
used with list or extract, volume-name is used as
a globing pattern.
--version Print gnutar program version number.
-w
--interactive
--confirmation Ask for confirmation for every action.
-W
--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.
--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.
--wildcards-match-slash
Exclude pattern wildcards match '/' (default).
--no-wildcards-match-slash
Exclude pattern wildcards do not match '/'.
-Z
--compress
--uncompress Filter the archive through compress(1).
-z
--gzip
--ungzip
--gunzip Filter the archive through gzip(1).
--use-compress-program program
Filter the archive through program (which must
accept -d to mean “decompress”).
-[0-7][lmh] Specify tape drive and density.
ENVIRONMENT
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 specifica‐
tion.
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.
SIMPLE_BACKUP_SUFFIX
Sets the backup suffix used by gnutar. Default is '~'.
TAPE Changes gnutar's default tape drive (which is still
overridden by the -f flag).
TAR_OPTIONS The environment variable TAR_OPTIONS can hold a set of
default options for gnutar. These options are inter‐
preted 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:
t, numbered
make numbered backups
nil, existing
numbered if numbered backups exist, simple
otherwise
never, simple
always make simple backups
Default behaviour is 'existing'.
FILES
/dev/sa0 The default tape drive.
EXAMPLES
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
or
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’.
SEE ALSObzip2(1), compress(1), gzip(1), pax(1), rmt(8), info tar
HISTORY
The gnutar format has a rich history, dating back to Sixth Edition UNIX.
The current implementation of gnutar is the GNU implementation, which
originated as the public-domain gnutar written by John Gilmore.
AUTHORS
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
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 subsequent archives.
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 minor) numbers.
BSD December 23, 2000 BSD
