TAR(1)

NAME
tar - an archiving utility

SYNOPSIS

  Traditional usage
tar {A|c|d|r|t|u|x}[GnSkUWOmpsMBiajJzZhPlRvwo] [ARG...]

  UNIX-style usage

tar -A [OPTIONS] ARCHIVE ARCHIVE

tar -c [-f ARCHIVE] [OPTIONS] [FILE...]

tar -d [-f ARCHIVE] [OPTIONS] [FILE...]

tar -t [-f ARCHIVE] [OPTIONS] [MEMBER...]

tar -r [-f ARCHIVE] [OPTIONS] [FILE...]

tar -u [-f ARCHIVE] [OPTIONS] [FILE...]

tar -x [-f ARCHIVE] [OPTIONS] [MEMBER...]

  GNU-style usage

tar {--catenate|--concatenate} [OPTIONS] ARCHIVE ARCHIVE

tar --create [--file ARCHIVE] [OPTIONS] [FILE...]

tar {--diff|--compare} [--file ARCHIVE] [OPTIONS] [FILE...]

tar --delete [--file ARCHIVE] [OPTIONS] [MEMBER...]

tar --append [-f ARCHIVE] [OPTIONS] [FILE...]

tar --list [-f ARCHIVE] [OPTIONS] [MEMBER...]

tar --test-label [--file ARCHIVE] [OPTIONS] [LABEL...]

tar --update [--file ARCHIVE] [OPTIONS] [FILE...]

tar --update [-f ARCHIVE] [OPTIONS] [FILE...]

tar {--extract|--get} [-f ARCHIVE] [OPTIONS] [MEMBER...]

NOTE
This manpage is a short description of GNU tar. For a detailed discussion, including examples and usage recommendations, refer to the GNU Tar Manual available in texinfo format. If the info reader and the tar documentation are properly installed on your system, the command

    info tar

should give you access to the complete manual.

You can also view the manual using the info mode in emacs(1), or find it in various formats online at

    http://www.gnu.org/software/tar/manual

If any discrepancies occur between this manpage and the GNU Tar Manual, the later shall be considered the authoritative source.

DESCRIPTION
GNU tar is an archiving program designed to store multiple files in a single file (an archive), and to manipulate such archives. The archive can be either a regular file or a device (e.g. a tape drive, hence the name of the program, which stands for tape archiver), which can be located either on the local or on a remote machine.

  Option styles
Options to GNU tar can be given in three different styles. In traditional style, the first argument is a cluster of option letters and all subsequent arguments supply arguments to those options that require them. The arguments are read in the same order as the option letters. Any command line words that remain after all options has been processed are treated as non-optional arguments: file or archive member names.

For example, the c option requires creating the archive, the v option requests the verbose operation, and the f option takes an argument that sets the name of the archive to operate upon. The following command, written in the traditional style, instructs tar to store all files from the directory /etc into the archive file etc.tar verbosely listing the files being archived:

    tar cfv a.tar /etc

In UNIX or short-option style, each option letter is prefixed with a single dash, as in other command line utilities. If an option takes argument, the argument follows it, either as a separate command line word, or immediately following the option. However, if the option takes an optional argument, the argument must follow the option letter without any intervening whitespace, as in -g/tmp/snar.db.

Any number of options not taking arguments can be clustered together after a single dash, e.g. -vkp. Options that take arguments (whether mandatory or optional), can appear at the end of such a cluster, e.g. -vkpf a.tar.

The example command above written in the short-option style could look like:

    tar -cvf a.tar /etc
    or
    tar -c -v -f a.tar /etc

In GNU or long-option style, each option begins with two dashes and has a meaningful name, consisting of lower-case letters and dashes. When used, the long option can be abbreviated to its initial letters, provided that this does not create ambiguity. Arguments to long options are supplied either as a separate command line word, immediately following the option, or separated from the option by an equals sign with no intervening whitespace. Optional arguments must always use the latter method.

Here are several ways of writing the example command in this style:

    tar --create --file a.tar --verbose /etc
or (abbreviating some options):
    tar --cre --file=a.tar --verb /etc

The options in all three styles can be intermixed, although doing so with old options is not encouraged.

  Operation mode
The options listed in the table below tell GNU tar what operation it is to perform. Exactly one of them must be given. Meaning of non-optional arguments depends on the operation mode requested.

-A, --catenate, --concatenate
    Append archive to the end of another archive. The arguments are treated as the names of archives to append. All archives must be of the same format as the archive they are appended to, otherwise the resulting archive might be unusable with non-GNU implementations of tar. Notice also that when more than one archive is given, the members from archives other than the first one will be accessible in the resulting archive only if using the -i (--ignore-zeros) option. Compressed archives cannot be concatenated.

-c, --create
    Create a new archive. Arguments supply the names of the files to be archived. Directories are archived recursively, unless the --no-recursion option is given.

-d, --diff, --compare
    Find differences between archive and file system. The arguments are optional and specify archive members to compare. If not given, the current working directory is assumed.

--delete
    Delete from the archive. The arguments supply names of the archive members to be removed. At least one argument must be given. This option does not operate on compressed archives. There is no short option equivalent.

-r, --append
    Append files to the end of an archive. Arguments have the same meaning as for -c (--create).

-t, --list
    List the contents of an archive. Arguments are optional. When given, they specify the names of the members to list.

--test-label
    Test the archive volume label and exit. When used without arguments, it prints the volume label (if any) and exits with status 0. When one or more command line arguments are given. tar compares the volume label with each argument. It exits with code 0 if a match is found, and with code 1 otherwise. No output is displayed, unless used together with the -v (--verbose) option. There is no short option equivalent for this option.

-u, --update
    Append files which are newer than the corresponding copy in the archive. Arguments have the same meaning as with -c and -r options.

-x, --extract, --get
    Extract files from an archive. Arguments are optional. When given, they specify names of the archive members to be extracted.

--show-defaults
    Show built-in defaults for various tar options and exit. No arguments are allowed.

-?, --help
    Display a short option summary and exit. No arguments allowed.

--usage
    Display a list of available options and exit. No arguments allowed.

--version
    Print program version and copyright information and exit.

OPTIONS

  Operation modifiers

--check-device
    Check device numbers when creating incremental archives (default).

-g, --listed-incremental=FILE
    Handle new GNU-format incremental backups. FILE is the name of a snapshot file, where tar stores additional information which is used to decide which files changed since the previous incremental dump and, consequently, must be dumped again. If FILE does not exist when creating an archive, it will be created and all files will be added to the resulting archive (the level 0 dump). To create incremental archives of non-zero level N, create a copy of the snapshot file created during the level N-1, and use it as FILE. When listing or extracting, the actual contents of FILE is not inspected, it is needed only due to syntactical requirements. It is therefore common practice to use /dev/null in its place.

-G, --incremental
    Handle old GNU-format incremental backups.

--ignore-failed-read
    Do not exit with nonzero on unreadable files.

--level=NUMBER
    Set dump level for created listed-incremental archive. Currently only --level=0 is meaningful: it instructs tar to truncate the snapshot file before dumping, thereby forcing a level 0 dump.

-n, --seek
    Assume the archive is seekable. Normally tar determines automatically whether the archive can be seeked or not. This option is intended for use in cases when such recognition fails. It takes effect only if the archive is open for reading (e.g. with --list or --extract options).

--no-check-device
    Do not check device numbers when creating incremental archives.

--no-seek
    Assume the archive is not seekable.

--occurrence[=N]
    Process only the Nth occurrence of each file in the archive. This option is valid only when used with one of the following subcommands: --delete, --diff, --extract or --list and when a list of files is given either on the command line or via the -T option. The default N is 1.

--restrict
    Disable the use of some potentially harmful options.

--sparse-version=MAJOR[.MINOR]
    Set version of the sparse format to use (implies --sparse). This option implies --sparse. Valid argument values are 0.0, 0.1, and 1.0. For a detailed discussion of sparse formats, refer to the GNU Tar Manual, appendix D, "Sparse Formats". Using info reader, it can be accessed running the following command: info tar 'Sparse Formats'.

-S, --sparse
    Handle sparse files efficiently. Some files in the file system may have segments which were actually never written (quite often these are database files created by such systems as DBM). When given this option, tar attempts to determine if the file is sparse prior to archiving it, and if so, to reduce the resulting archive size by not dumping empty parts of the file.

  Overwrite control
These options control tar actions when extracting a file over an existing copy on disk.

-k, --keep-old-files
    Don't replace existing files when extracting.

--keep-newer-files
    Don't replace existing files that are newer than their archive copies.

--no-overwrite-dir
    Preserve metadata of existing directories.

--one-top-level[=DIR]
    Extract all files into DIR, or, if used without argument, into a subdirectory named by the base name of the archive (minus standard compression suffixes recognizable by --auto-compress).

--overwrite
    Overwrite existing files when extracting.

--overwrite-dir
    Overwrite metadata of existing directories when extracting (default).

--recursive-unlink
    Recursively remove all files in the directory prior to extracting it.

--remove-files
    Remove files from disk after adding them to the archive.

-U, --unlink-first
    Remove each file prior to extracting over it.

-W, --verify
    Verify the archive after writing it.

  Output stream selection

--ignore-command-error

Ignore subprocess exit codes.

--no-ignore-command-error
    Treat non-zero exit codes of children as error (default).

-O, --to-stdout
    Extract files to standard output.

--to-command=COMMAND
    Pipe extracted files to COMMAND. The argument is the pathname of an external program, optionally with command line arguments. The program will be invoked and the contents of the file being extracted supplied to it on its standard output. Additional data will be supplied via the following environment variables:

    TAR_FILETYPE
        Type of the file. It is a single letter with the following meaning:

        	f	Regular file
        	d	Directory
        	l	Symbolic link
        	h	Hard link
        	b	Block device
        	c	Character device
        Currently only regular files are supported.

    TAR_MODE
        File mode, an octal number.

    TAR_FILENAME
        The name of the file.

    TAR_REALNAME
        Name of the file as stored in the archive.

    TAR_UNAME
        Name of the file owner.

    TAR_GNAME
        Name of the file owner group.

    TAR_ATIME
        Time of last access. It is a decimal number, representing seconds since the Epoch. If the archive provides times with nanosecond precision, the nanoseconds are appended to the timestamp after a decimal point.

    TAR_MTIME
        Time of last modification.

    TAR_CTIME
        Time of last status change.

    TAR_SIZE
        Size of the file.

    TAR_UID
        UID of the file owner.

    TAR_GID
        GID of the file owner.
    Additionally, the following variables contain information about tar operation mode and the archive being processed:

    TAR_VERSION
        GNU tar version number.

    TAR_ARCHIVE
        The name of the archive tar is processing.

    TAR_BLOCKING_FACTOR
        Current blocking factor, i.e. number of 512-byte blocks in a record.

    TAR_VOLUME
        Ordinal number of the volume tar is processing (set if reading a multi-volume archive).

    TAR_FORMAT
        Format of the archive being processed. One of: gnu, oldgnu, posix, ustar, v7. TAR_SUBCOMMAND A short option (with a leading dash) describing the operation tar is executing.

  Handling of file attributes

--atime-preserve[=METHOD]
    Preserve access times on dumped files, either by restoring the times after reading (METHOD=replace, this is the default) or by not setting the times in the first place (METHOD=system)

--delay-directory-restore
    Delay setting modification times and permissions of extracted directories until the end of extraction. Use this option when extracting from an archive which has unusual member ordering.

--group=NAME
    Force NAME as group for added files.

--mode=CHANGES
    Force symbolic mode CHANGES for added files.

--mtime=DATE-OR-FILE
    Set mtime for added files. DATE-OR-FILE is either a date/time in almost arbitrary formate, or the name of an existing file. In the latter case the mtime of that file will be used.

-m, --touch
    Don't extract file modified time.

--no-delay-directory-restore
    Cancel the effect of the prior --delay-directory-restore option.

--no-same-owner
    Extract files as yourself (default for ordinary users).

--no-same-permissions
    Apply the user's umask when extracting permissions from the archive (default for ordinary users).

--numeric-owner
    Always use numbers for user/group names.

--owner=NAME
    Force NAME as owner for added files.

-p, --preserve-permissions, --same-permissions
    extract information about file permissions (default for superuser)

--preserve
    Same as both -p and -s.

--same-owner
    Try extracting files with the same ownership as exists in the archive (default for superuser).

-s, --preserve-order, --same-order
    Sort names to extract to match archive

--sort=ORDER
    When creating an archive, sort directory entries according to ORDER, which is one of none, name, or inode. The default is --sort=none, which stores archive members in the same order as returned by the operating system. Using --sort=name ensures the member ordering in the created archive is uniform and reproducible. Using --sort=inode reduces the number of disk seeks made when creating the archive and thus can considerably speed up archivation. This sorting order is supported only if the underlying system provides the necessary information.

  Device selection and switching

-f, --file=ARCHIVE
    Use archive file or device ARCHIVE. If this option is not given, tar will first examine the environment variable `TAPE'. If it is set, its value will be used as the archive name. Otherwise, tar will assume the compiled-in default. The default value can be inspected either using the --show-defaults option, or at the end of the tar --help output. An archive name that has a colon in it specifies a file or device on a remote machine. The part before the colon is taken as the machine name or IP address, and the part after it as the file or device pathname, e.g.:
        --file=remotehost:/dev/sr0
    An optional username can be prefixed to the hostname, placing a @ sign between them. By default, the remote host is accessed via the rsh(1) command. Nowadays it is common to use ssh(1) instead. You can do so by giving the following command line option:
        --rsh-command=/usr/bin/ssh
    The remote mashine should have the rmt(8) command installed. If its pathname does not match tar's default, you can inform tar about the correct pathname using the --rmt-command option.

--force-local
    Archive file is local even if it has a colon.

-F, --info-script=COMMAND, --new-volume-script=COMMAND
    Run COMMAND at the end of each tape (implies -M). The command can include arguments. When started, it will inherit tar's environment plus the following variables:

    TAR_VERSION
        GNU tar version number.

    TAR_ARCHIVE
        The name of the archive tar is processing.

    TAR_BLOCKING_FACTOR
        Current blocking factor, i.e. number of 512-byte blocks in a record.

    TAR_VOLUME
        Ordinal number of the volume tar is processing (set if reading a multi-volume archive).

    TAR_FORMAT
        Format of the archive being processed. One of: gnu, oldgnu, posix, ustar, v7.

    TAR_SUBCOMMAND
        A short option (with a leading dash) describing the operation tar is executing.

    TAR_FD
        File descriptor which can be used to communicate the new volume name to tar.
    If the info script fails, tar exits; otherwise, it begins writing the next volume.

-L, --tape-length=
    Change tape after writing Nx1024 bytes. If N is followed by a size suffix (see the subsection Size suffixes below), the suffix specifies the multiplicative factor to be used instead of 1024. This option implies -M.

-M, --multi-volume
    Create/list/extract multi-volume archive.

--rmt-command=COMMAND
    Use COMMAND instead of rmt when accessing remote archives. See the description of the -f option, above.

--rsh-command=COMMAND
    Use COMMAND instead of rsh when accessing remote archives. See the description of the -f option, above.

--volno-file=FILE
    When this option is used in conjunction with --multi-volume, tar will keep track of which volume of a multi-volume archive it is working in FILE.

  Device blocking

-b, --blocking-factor=BLOCKS
    Set record size to BLOCKSx512 bytes.

-B, --read-full-records
    When listing or extracting, accept incomplete input records after end-of-file marker.

-i, --ignore-zeros
    Ignore zeroed blocks in archive. Normally two consecutive 512-blocks filled with zeroes mean EOF and tar stops reading after encountering them. This option instructs it to read further and is useful when reading archives created with the -A option.

--record-size=NUMBER
    Set record size. NUMBER is the number of bytes per record. It must be multiple of 512. It can can be suffixed with a size suffix, e.g. --record-size=10K, for 10 Kilobytes. See the subsection Size suffixes, for a list of valid suffixes.

  Archive format selection

-H, --format=FORMAT
    Create archive of the given format. Valid formats are:

    gnu GNU tar 1.13.x format

    oldgnu
        GNU format as per tar <= 1.12.

    pax, posix
        POSIX 1003.1-2001 (pax) format.

    ustar
        POSIX 1003.1-1988 (ustar) format.

    v7  Old V7 tar format.

--old-archive, --portability
    Same as --format=v7.

--pax-option=keyword[[:]=value][,keyword[[:]=value]]...
    Control pax keywords when creating PAX archives (-H pax). This option is equivalent to the -o option of the pax(1)utility.

--posix
    Same as --format=posix.

-V, --label=TEXT
    Create archive with volume name TEXT. If listing or extracting, use TEXT as a globbing pattern for volume name.

  Compression options

-a, --auto-compress
    Use archive suffix to determine the compression program.

-I, --use-compress-program=COMMAND
    Filter data through COMMAND. It must accept the -d option, for decompression. The argument can contain command line options.

-j, --bzip2
    Filter the archive through bzip2(1).

-J, --xz
    Filter the archive through xz(1).

--lzip
    Filter the archive through lzip(1).

--lzma
    Filter the archive through lzma(1).

--lzop
    Filter the archive through lzop(1).

--no-auto-compress
    Do not use archive suffix to determine the compression program.

-z, --gzip, --gunzip, --ungzip
    Filter the archive through gzip(1).

-Z, --compress, --uncompress
    Filter the archive through compress(1).

  Local file selection

--add-file=FILE
    Add FILE to the archive (useful if its name starts with a dash).

--backup[=CONTROL]
    Backup before removal. The CONTROL argument, if supplied, controls the backup policy. Its valid values are:

    none, off
        Never make backups.

    t, numbered
        Make numbered backups.

    nil, existing
        Make numbered backups if numbered backups exist, simple backups otherwise.

    never, simple
        Always make simple backups
    If CONTROL is not given, the value is taken from the VERSION_CONTROL environment variable. If it is not set, existing is assumed.

-C, --directory=DIR
    Change to directory DIR.

--exclude=PATTERN
    Exclude files matching PATTERN, a glob(3)-style wildcard pattern.

--exclude-backups
    Exclude backup and lock files.

--exclude-caches
    Exclude contents of directories containing file CACHEDIR.TAG, except for the tag file itself.

--exclude-caches-all
    Exclude directories containing file CACHEDIR.TAG and the file itself.

--exclude-caches-under
    Exclude everything under directories containing CACHEDIR.TAG

--exclude-ignore=FILE
    Before dumping a directory, see if it contains FILE. If so, read exclusion patterns from this file. The patterns affect only the directory itself.

--exclude-ignore-recursive=FILE
    Same as --exclude-ignore, except that patterns from FILE affect both the directory and all its subdirectories.

--exclude-tag=FILE
    Exclude contents of directories containing FILE, except for FILE itself.

--exclude-tag-all=FILE
    Exclude directories containing FILE.

--exclude-tag-under=FILE
    Exclude everything under directories containing FILE.

--exclude-vcs
    Exclude version control system directories.

--exclude-vcs-ignores
    Exclude files that match patterns read from VCS-specific ignore files. Supported files are: .cvsignore, .gitignore, .bzrignore, and .hgignore.

-h, --dereference
    Follow symlinks; archive and dump the files they point to.

--hard-dereference
    Follow hard links; archive and dump the files they refer to.

-K, --starting-file=MEMBER
    Begin at the given member in the archive.

--newer-mtime=DATE
    Work on files whose data changed after the DATE. If DATE starts with / or . it is taken to be a file name; the mtime of that file is used as the date.

--no-null
    Disable the effect of the previous --null option.

--no-recursion
    Avoid descending automatically in directories.

--no-unquote
    Do not unquote input file or member names.

--null
    Instruct subsequent -T options to read null-terminated names, disable handling of the -C option read from the file.

-N, --newer=DATE, --after-date=DATE
    Only store files newer than DATE. If DATE starts with / or . it is taken to be a file name; the ctime of that file is used as the date.

--one-file-system
    Stay in local file system when creating archive.

-P, --absolute-names
    Don't strip leading slashes from file names when creating archives.

--recursion
    Recurse into directories (default).

--suffix=STRING
    Backup before removal, override usual suffix. Default suffix is ~, unless overridden by environment variable SIMPLE_BACKUP_SUFFIX.

-T, --files-from=FILE
    Get names to extract or create from FILE.

--unquote
    Unquote file or member names (default).

-X, --exclude-from=FILE
    Exclude files matching patterns listed in FILE.

  File name transformations

--strip-components=NUMBER
    Strip NUMBER leading components from file names on extraction.

--transform=EXPRESSIONR, --xform=EXPRESSION
    Use sed replace EXPRESSION to transform file names.

  File name matching options
These options affect both exclude and include patterns.

--anchored
    Patterns match file name start.

--ignore-case
    Ignore case.

--no-anchored
    Patterns match after any / (default for exclusion).

--no-ignore-case
    Case sensitive matching (default).

--no-wildcards
    Verbatim string matching.

--no-wildcards-match-slash
    Wildcards do not match /.

--wildcards
    Use wildcards (default for exclusion).

--wildcards-match-slash
    Wildcards match / (default for exclusion).

  Informative output

--checkpoint[=N]
    Display progress messages every Nth record (default 10).

--checkpoint-action=ACTION
    Run ACTION on each checkpoint.

--full-time
    Print file time to its full resolution.

--index-file=FILE
    Send verbose output to FILE.

-l, --check-links
    Print a message if not all links are dumped.

--no-quote-chars=STRING
    Disable quoting for characters from STRING.

--quote-chars=STRING
    Additionally quote characters from STRING.

--quoting-style=STYLE
    Set quoting style for file and member names. Valid values for STYLE are literal, shell, shell-always, c, c-maybe, escape, locale, clocale.

-R, --block-number
    Show block number within archive with each message.

--show-omitted-dirs
    When listing or extracting, list each directory that does not match search criteria.

--show-transformed-names, --show-stored-names
    Show file or archive names after transformation by --strip and --transform options.

--totals[=SIGNAL]
    Print total bytes after processing the archive. If SIGNAL is given, print total bytes when this signal is delivered. Allowed signals are: SIGHUP, SIGQUIT, SIGINT, SIGUSR1, and SIGUSR2. The SIG prefix can be omitted.

--utc
    Print file modification times in UTC.

-v, --verbose
    Verbosely list files processed.

--warning=KEYWORD
    Enable or disable warning messages identified by KEYWORD. The messages are suppressed if KEYWORD is prefixed with no- and enabled otherwise. Multiple --warning messages accumulate. Keywords controlling general tar operation:

    all Enable all warning messages. This is the default.

    none
        Disable all warning messages.

    filename-with-nuls
        "%s: file name read contains nul character"

    alone-zero-block
        "A lone zero block at %s"

    Keywords applicable for tar --create:

    cachedir
        "%s: contains a cache directory tag %s; %s"

    file-shrank
        "%s: File shrank by %s bytes; padding with zeros"

    xdev
        "%s: file is on a different filesystem; not dumped"

    file-ignored
        "%s: Unknown file type; file ignored"
        "%s: socket ignored"
        "%s: door ignored"

    file-unchanged
        "%s: file is unchanged; not dumped"

    ignore-archive
        "%s: file is the archive; not dumped"

    file-removed
        "%s: File removed before we read it"

    file-changed
        "%s: file changed as we read it"

    Keywords applicable for tar --extract:

    timestamp
        "%s: implausibly old time stamp %s"
        "%s: time stamp %s is %s s in the future"

    contiguous-cast
        "Extracting contiguous files as regular files"

    symlink-cast
        "Attempting extraction of symbolic links as hard links"

    unknown-cast
        "%s: Unknown file type '%c', extracted as normal file"

    ignore-newer
        "Current %s is newer or same age"

    unknown-keyword
        "Ignoring unknown extended header keyword '%s'"

    decompress-program
        Controls verbose description of failures occurring when trying to run alternative decompressor programs. This warning is disabled by default (unless --verbose is used). A common example of what you can get when using this warning is:
            $ tar --warning=decompress-program -x -f archive.Z
            tar (child): cannot run compress: No such file or directory
            tar (child): trying gzip
        This means that tar first tried to decompress archive.Z using compress, and, when that failed, switched to gzip.

    record-size
        "Record size = %lu blocks"

    Keywords controlling incremental extraction:

    rename-directory
        "%s: Directory has been renamed from %s"
        "%s: Directory has been renamed"

    new-directory
        "%s: Directory is new"

    xdev
        "%s: directory is on a different device: not purging"

    bad-dumpdir
        "Malformed dumpdir: 'X' never used"

-w, --interactive, --confirmation
    Ask for confirmation for every action.

  Compatibility options

-o  When creating, same as --old-archive. When extracting, same as --no-same-owner.

  Size suffixes

	Suffix	Units	Byte Equivalent
	b	Blocks	SIZE x 512
	B	Kilobytes	SIZE x 1024
	c	Bytes	SIZE
	G	Gigabytes	SIZE x 1024^3
	K	Kilobytes	SIZE x 1024
	k	Kilobytes	SIZE x 1024
	M	Megabytes	SIZE x 1024^2
	P	Petabytes	SIZE x 1024^5
	T	Terabytes	SIZE x 1024^4
	w	Words	SIZE x 2

RETURN VALUE
Tar exit code indicates whether it was able to successfully perform the requested operation, and if not, what kind of error occurred.

0   Successful termination.

1   Some files differ. If tar was invoked with the --compare (--diff, -d) command line option, this means that some files in the archive differ from their disk counterparts. If tar was given one of the --create, --append or --update options, this exit code means that some files were changed while being archived and so the resulting archive does not contain the exact copy of the file set.

2   Fatal error. This means that some fatal, unrecoverable error occurred.

If a subprocess that had been invoked by tar exited with a nonzero exit code, tar itself exits with that code as well. This can happen, for example, if a compression option (e.g. -z) was used and the external compressor program failed. Another example is rmt failure during backup to a remote device.

SEE ALSO
bzip2(1), compress(1), gzip(1), lzma(1), lzop(1), rmt(8), symlink(7), tar(5), xz(1).

Complete tar manual: run info tar or use emacs(1) info mode to read it.

Online copies of GNU tar documentation in various formats can be found at:

http://www.gnu.org/software/tar/manual

BUG REPORTS
Report bugs to <bug-tar@gnu.org>.

COPYRIGHT
Copyright © 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.