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tar -- manipulate tape archives

tar {-c} [options] [files | directories]
tar {-r | -u} -f archive-file [options] [files | directories]
tar {-t | -x} [options] [patterns]
tar [bundled-flags args] [file | pattern …]

Creates and manipulates streaming archive files, originally for storage to magnetic tape.
This implementation can extract from tar, pax, cpio, zip, jar, ar, and ISO 9660 cdrom images and can create tar, pax, cpio, ar, and shar archives see libarchive-formats.

First argument is mode :

-c Create archive
-t Table of contents is listed to stdout.
-x Extract from the archive.
-r Refresh, new entries are appended to the archive.
only on uncompressed archives stored in regular files. -f is required.
-u Update an archive, new entries are added if modification date newer than the corresponding entry in the archive.
Only on uncompressed archives stored in regular files. -f is required.
When creating or updating an archive, files or directories are added in the order specified.
By default the contents of directories are archived (recursion).

In extract or t list mode, the entire command line is read and parsed before the archive is opened.
pathnames or patterns on the command line indicate which items in the archive should be processed.
Patterns are shell-style globbing patterns as documented in tcsh.

Options

-v verbose
For create and extract , lists file as processed.
For table of contents, produces ls -l style output.
-f file file is the archive. To accept input via pipe or standard input or to send output via pipe or standard output use - .
-C directory changes directory before adding the files.
In extract mode, change directories before extracting entries .
-H Symbolic links named on the command line are followed; the target of the link is archived.
-L
-h
All symbolic links are followed. the target of the link is archived.
--check-links
-l
Issue a warning message unless all links to each file are archived.
--nodump Honor the nodump file flag by skipping this file.
Create and Refresh specific options
--newer date Only include files and directories newer than the specified date. This compares ctime
--newer-mtime date compares mtimes
--newer-than file Only include files and directories newer than the specified file. This compares ctime
--newer-mtime-than file compares mtime
Create specific options
-j
-y
Compress with bzip2
-z Compress with gzip
-Z Compress with compress
Create, Refresh and Update specific options
--one-file-system Do not cross mount points.
-n Do not recursively archive the contents of directories.
--format format cpio, pax, shar, or ustar. In refresh and update modes, format must be compatible with the existing archive .
-o --format ustar
@archivearchive is opened and the entries in it is appended to the current archive. Example:
tar -c -f new.tar newfile @original.tar
Creates new.tar containing newfile and all of the files in original.tar.
In contrast,
tar -c -f new.tar newfile original.tar
Creates new.tar with only two entries.

tar -czf - --format pax @-
reads an archive from standard input (whose format is determined automatically) and
creates a gzip-compressed pax-format archive on stdout. Used to convert from one format to another.
eXtract specific options
-k keep existing files, even if older.
If an archive has been refreshed or updated, a file which occurs more than once, later copies will not overwrite earlier copies, not likely what you want!
--keep-newer-files Do not overwrite existing files that are newer than the versions in the archive.
-p Preserve file permissions: owner, file modes, file flags and ACLs.
Default: newly-created files are owned by the running user ,
Mode is restored for newly-created files, other entries receive default permissions.

As root, restores the owner unless -o is also specified.

-o ownership is set user and group of the running user rather than the original.
As root with -p modes and flags restored, but ACLs or owner information is discarded.
-m modification times are not preserved. Default: Preserved.
--numeric-owner numeric UID and GID are used, not named.
Warning restoring to a different system or with a significantly /etc/passwd can corrupt ownership.
--chroot to the current directory after processing -C before extracting files.
-S Sparse files are created for blocks containing only NULL bytes, seek over it otherwise. See dd conv=sparse .
--strip-components n n Leading path elements are removed.

Example: With n of 3; files from /home/secretProject/version2/… can be restored to Production/…

The pathname is edited after checking inclusion/exclusion patterns but before security checks.
Pathnames with fewer elements are silently skipped.

--exclude pattern
-X
files or directories matching the pattern.
Exclusions take precedence over patterns or filenames on the command line.
-I filename
-T
Include names or patterns in filename
Names are terminated by unless --null is specified, and also disables the special handling of lines containing -C on a line by itself which cause the current directory to be changed to the directory specified on the following line.
--null with -I, -T, or -X) Filenames or patterns are separated by null characters, not by newlines. Used to read filenames output by the find -print0 helpful when files contain spaces
--include pattern Process only files or directories that match the specified pattern.
exclusions specified with --exclude take precedence over inclusions.
If no inclusions are explicitly specified, all entries are processed by default.
The --include useful when filtering archives. For example, the command
tar -v -c -f new.tar --include='*foo*' @old.tgz
Verbosely creates new.tar containing only the entries from old.tgz containing the string foo.
-P Preserve pathnames.
By default, absolute pathnames (those that begin with a / character) have the leading slash removed both when creating archives and extracting from them.
tar does not extract archive entries whose pathnames contain .. or whose target directory would be altered by a symlink. This suppresses these behaviors.
-O In extract (-x) mode, files are written to stdout (perhaps piped to another command).
In Table of Contents (-t) mode, the listing is written to stderr. Default: stdout .
-q
--fast-read
Extract or list the first entry that matches each pattern or filename operand.
When all patterns/filenames are matched processing stops.
If the archive was refreshed there is the possibility that a newer version is not found.
Default: archive is read to the end, as there can be multiple entries with the same name ( if the archive was refreshed ) and later entries overwrite earlier entries.
-s cmdSubstitue characters in names per cmd of the form:
/old/repl/[g][p][s].
old is a basic regular expression. ~ is substituted with the match, 1 to 9 with the content of the corresponding captured group.
g globally match but stop on the first unmatched pattern.
s Symbolic link's value are used old for pattern matching.
p print (output) the original path name and the new path name is output to standard error after a successful substitution
-U (Extracting) Unlink(remove) files before creating them.
With this option, existing hardlinks is broken, as will any symlink that would affect the location of an extracted file.
Default existing files are overwriten, which preserves existing hardlinks.

This may be useful if files being extracted to existing directory are large relative to current free space or the archive had been refreshed and multiple copys of files exist.

--use-compress-program pgm Pipe through pgm Default: builtin compression
--options key=value passed to modules that handle particular formats
key enabled in every module that supports it. Equivalent to key=1.
!key disable
module:key=value
module:key
module:!key
provided only to modules whose name matches module.
iso9660:!joliet
!joliet
disable
iso9660:!rockridgei
!rockridge
disable
mtree:keyword specify which mtree keywords are included in the output. cksum, device, flags, gid, gname, indent, link, md5, mode, nlink, rmd160, sha1, sha256, sha384, sha512, size, time, uid, uname
Default : device, flags, gid, gname, link, mode, nlink, size, time, type, uid, uname
mtree:all Enables all keywords. mtree:!all to disable all keywords.
mtree:use-set Enable generation of /set lines in the output.
mtree:indent Produce human-readable output by indenting options and splitting lines to fit into 80 columns.
gzip:compression-level decimal integer 0-9 compression level.
xz:compression-level
zip:compression=type store (uncompressed) and deflate (gzip ).
--version display versions and exit.
-w Ask for confirmation for every action.
-b blocksize in 512-byte records, . As a rule, this argument is only needed when reading from or writing to tape drives, and usually not even then as the default block size of 20 records (10240 bytes) is very common.
ENVIRONMENT LANG The locale to use. See environ(7) for more information.
TZ The timezone to use when displaying dates. See environ(7) for more information.

EXIT STATUS

The tar utility exits 0 on success, and >0 if an error occurs.

EXAMPLES

The following creates a new archive called file.tar.gz that contains two files source.c and source.h: tar -czf file.tar.gz source.c source.h

To view a detailed table of contents for this archive: tar -tvf file.tar.gz

To examine the contents of an ISO 9660 cdrom image: tar -tf image.iso

To move file hierarchies, invoke tar as
tar -cf - -C srcdir . | tar -xpf - -C destdir

or more traditionally
cd srcdir ; tar -cf - . | (cd destdir ; tar -xpf -)

In create mode, the list of files and directories to be archived can also include directory change instructions of the form -Cfoo/baz and archive inclusions of the form @archive-file. For example, the command line

tar -c -f new.tar foo1 @old.tgz -C/tmp foo2
will create new.tar. tar will read the file foo1 from the current directory and add it to the output archive. It will then read each entry from old.tgz and add those entries to the output archive. Finally, it will switch to the /tmp directory and add foo2 to the output archive.

An input file in mtree format can be used to create an output archive with arbitrary ownership, permissions, or names that differ from existing data on disk:

           $ cat input.mtree
           #mtree
           usr/bin uid=0 gid=0 mode=0755 type=dir
           usr/bin/ls uid=0 gid=0 mode=0755 type=file content=myls
           $ tar -cvf output.tar @input.mtree
--newer and --newer-mtime accept a variety of common date and time specifications, examples include:
     12 Mar 2005 7:14:29pm, 2005-03-12 19:14, 5 minutes ago, and 19:14 PST May 1.

COMPATIBILITY

The bundled-arguments format is supported for compatibility with historic implementations. It consists of an initial word (with no leading - character) in which each character indicates an option. Arguments follow as separate words. The order of the arguments must match the order of the corresponding characters in the bundled command word. For example,
tar tbf 32 file.tar
specifies three flags t, b, and f. The b and f flags both require arguments, so there must be two additional items on the command line. The 32 is the argument to the b flag, and file.tar is the argument to the f flag.

The mode options c, r, t, u, and x and the options b, f, l, m, o, v, and w comply with SUSv2.

For maximum portability, scripts that invoke tar should use the bundled-argument format above, should limit themselves to the c, t, and x modes, and the b, f, m, v, and w options.

Additional long options are provided to improve compatibility with other tar implementations.

SECURITY

Certain security issues are common to many archiving programs. Carefully-crafted archives can request that tar extract files to locations outside of the target directory. This can cause unintended overwriting of files.
If the archive is being extracted by the superuser, any file on the system can potentially be overwritten. This can happen by: To protect yourself, you should be wary of any archives that come from untrusted sources. You should examine the contents of an archive with
tar -tf filename
before extraction.
Use -k to ensure that tar will not overwrite any existing files or -U to remove any pre-existing files.
You should generally not extract archives while running with super-user privileges.
-P disables the security checks above and allows you to extract an archive while preserving any absolute pathnames, .. components, or symlinks to other directories.

SEE ALSO

bzip2(1), compress(1), cpio(1), gzip(1), mt(1), pax(1), shar(1), libarchive(3), libarchive-formats(5), tar(5)

STANDARDS

There is no current POSIX standard for the tar command; it appeared in ISO/IEC 9945-1:1996 (POSIX.1) but was dropped from IEEE Std 1003.1-2001 (POSIX.1). The options used by this imple- mentation were developed by surveying a number of existing tar implementations as well as the old POSIX specification for tar and the current POSIX specification for pax.

The ustar and pax interchange file formats are defined by IEEE Std 1003.1-2001 (POSIX.1) for the pax command.

BUGS

This program follows ISO/IEC 9945-1:1996 (POSIX.1) for the definition of the -l option,
GNU tar prior to version 1.15 treated -l as a synonym for the --one-file-system option.

The -C dir option may differ from historic implementations.

All archive output is written in correctly-sized blocks, even if the output is being compressed. Whether or not the last output block is padded to a full block size varies depending on the format and the output device. For tar and cpio formats, the last block of output is padded to a full block size if the output is being written to standard output or to a character or block device such as a tape drive. If the output is being written to a regular file, the last block will not be padded. Many compressors, including gzip(1) and bzip2(1), complain about the null padding when decompressing an archive created by tar, although they still extract it correctly.

The compression and decompression is implemented internally, so there may be insignificant differences between the compressed output generated by
tar -czf - file

and that generated by
tar -cf - file | gzip

The default should be to read and write archives to the standard I/O paths, but tradition (and POSIX) dictates otherwise.

The r and u modes require that the archive be uncompressed and located in a regular file on disk. Other archives can be modified using c mode with the @archive-file extension.

To archive a file called @foo or -foo you must specify it as ./@foo or ./-foo, respectively.

In create mode, a leading ./ is always removed. A leading / is stripped unless the -P option is specified.

There needs to be better support for file selection on both create and extract.

There is not yet any support for multi-volume archives or for archiving sparse files.

Converting between dissimilar archive formats (such as tar and cpio) using the @- convention can cause hard link information to be lost. (This is a consequence of the incompatible ways that different archive formats store hardlink information.)

There are alternative long options for many of the short options.

Uses libarchive-formats.