TAR(1)                         GNU TAR Manual                         TAR(1)

NAME         top

       tar - an archiving utility

SYNOPSIS         top

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

   UNIX-style usage

       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         top

       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

           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


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

DESCRIPTION         top

       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 let‐
       ter 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
       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, immedi‐
       ately 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 argu‐
              ments are optional and specify archive members to compare.  If
              not given, the current working directory is assumed.

              Delete from the archive.  The arguments supply names of the
              archive members to be removed.  At least one argument must be

              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 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

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

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

              Display a list of available options and exit.  No arguments

              Print program version and copyright information and exit.

OPTIONS         top

   Operation modifiers
              Check device numbers when creating incremental archives

       -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.

              Use METHOD to detect holes in sparse files.  This option
              implies --sparse.  Valid values for METHOD are seek and raw.
              Default is seek with fallback to raw when not applicable.

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

              Do not exit with nonzero on unreadable files.

              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).

              Do not check device numbers when creating incremental

              Assume the archive is not seekable.

              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.

              Disable the use of some potentially harmful options.

              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

   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.

              Don't replace existing files that are newer than their archive

              Preserve metadata of existing directories.

              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

              Overwrite existing files when extracting.

              Overwrite metadata of existing directories when extracting

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

              Remove files from disk after adding them to the archive.

              Don't replace existing files when extracting, silently skip
              over them.

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

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

   Output stream selection

       Ignore subprocess exit codes.

              Treat non-zero exit codes of children as error (default).

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

              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:

                     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.

                     File mode, an octal number.

                     The name of the file.

                     Name of the file as stored in the archive.

                     Name of the file owner.

                     Name of the file owner group.

                     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.

                     Time of last modification.

                     Time of last status change.

                     Size of the file.

                     UID of the file owner.

                     GID of the file owner.

              Additionally, the following variables contain information
              about tar operation mode and the archive being processed:

                     GNU tar version number.

                     The name of the archive tar is processing.

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

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

                     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
              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 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.

              Force NAME as group for added files.  If GID is not supplied,
              NAME can be either a user name or numeric GID.  In this case
              the missing part (GID or name) will be inferred from the
              current host's group database.

              When used with --group-map=FILE, affects only those files
              whose owner group is not listed in FILE.

              Read group translation map from FILE.  Empty lines are
              ignored.  Comments are introduced with # sign and extend to
              the end of line.  Each non-empty line in FILE defines
              translation for a single group.  It must consist of two
              fields, delimited by any amount of whitespace:

              OLDGRP NEWGRP[:NEWGID]

              OLDGRP is either a valid group name or a GID prefixed with +.
              Unless NEWGID is supplied, NEWGRP must also be either a valid
              group name or a +GID.  Otherwise, both NEWGRP and NEWGID need
              not be listed in the system group database.

              As a result, each input file with owner group OLDGRP will be
              stored in archive with owner group NEWGRP and GID NEWGID.

              Force symbolic mode CHANGES for added files.

              Set mtime for added files.  DATE-OR-FILE is either a date/time
              in almost arbitrary format, 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.

              Cancel the effect of the prior --delay-directory-restore

              Extract files as yourself (default for ordinary users).

              Apply the user's umask when extracting permissions from the
              archive (default for ordinary users).

              Always use numbers for user/group names.

              Force NAME as owner for added files.  If UID is not supplied,
              NAME can be either a user name or numeric UID.  In this case
              the missing part (UID or name) will be inferred from the cur‐
              rent host's user database.

              When used with --owner-map=FILE, affects only those files
              whose owner is not listed in FILE.

              Read owner translation map from FILE.  Empty lines are
              ignored.  Comments are introduced with # sign and extend to
              the end of line.  Each non-empty line in FILE defines transla‐
              tion for a single UID.  It must consist of two fields, delim‐
              ited by any amount of whitespace:

              OLDUSR NEWUSR[:NEWUID]

              OLDUSR is either a valid user name or a UID prefixed with +.
              Unless NEWUID is supplied, NEWUSR must also be either a valid
              user name or a +UID.  Otherwise, both NEWUSR and NEWUID need
              not be listed in the system user database.

              As a result, each input file owned by OLDUSR will be stored in
              archive with owner name NEWUSR and UID NEWUID.

       -p, --preserve-permissions, --same-permissions
              extract information about file permissions (default for supe‐

              Same as both -p and -s.

              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

              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 archi‐
              vation.  This sorting order is supported only if the underly‐
              ing system provides the necessary information.

   Extended file attributes
       --acls Enable POSIX ACLs support.

              Disable POSIX ACLs support.

              Enable SELinux context support.

              Disable SELinux context support.

              Enable extended attributes support.

              Disable extended attributes support.

              Specify the exclude pattern for xattr keys.  PATTERN is a
              POSIX regular expression, e.g. --xattrs-exclude='^user.', to
              exclude attributes from the user namespace.

              Specify the include pattern for xattr keys.  PATTERN is a
              POSIX regular expression.

   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 out‐

              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.:


              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) com‐
              mand.  Nowadays it is common to use ssh(1) instead.  You can
              do so by giving the following command line option:


              The remote machine 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.

              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:

                     GNU tar version number.

                     The name of the archive tar is processing.

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

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

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

                     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=N
              Change tape after writing Nx1024 bytes.  If N is followed by a
              size suffix (see the subsection Size suffixes below), the suf‐
              fix specifies the multiplicative factor to be used instead of

              This option implies -M.

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

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

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

              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.

              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.

              Control pax keywords when creating PAX archives (-H pax).
              This option is equivalent to the -o option of the

              Same as --format=posix.

       -V, --label=TEXT
              Create archive with volume name TEXT.  If listing or extract‐
              ing, 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

       -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).

              Do not use archive suffix to determine the compression pro‐

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

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

   Local file selection
              Add FILE to the archive (useful if its name starts with a

              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 VER‐
              SION_CONTROL environment variable.  If it is not set, existing
              is assumed.

       -C, --directory=DIR
              Change to DIR before performing any operations.  This option
              is order-sensitive, i.e. it affects all options that follow.

              Exclude files matching PATTERN, a glob(3)-style wildcard pat‐

              Exclude backup and lock files.

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

              Exclude directories containing file CACHEDIR.TAG and the file

              Exclude everything under directories containing CACHEDIR.TAG

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

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

              Exclude contents of directories containing FILE, except for
              FILE itself.

              Exclude directories containing FILE.

              Exclude everything under directories containing FILE.

              Exclude version control system directories.

              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.

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

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

              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.

              Disable the effect of the previous --null option.

              Avoid descending automatically in directories.

              Do not unquote input file or member names.

              Treat each line read from a file list as if it were supplied
              in the command line.  I.e., leading and trailing whitespace is
              removed and, if the resulting string begins with a dash, it is
              treated as tar command line option.

              This is the default behavior.  The --no-verbatim-files-from
              option is provided as a way to restore it after --verba‐
              tim-files-from option.

              This option is positional: it affects all --files-from options
              that occur after it in, until --verbatim-files-from option or
              end of line, whichever occurs first.

              It is implied by the --no-null option.

       --null Instruct subsequent -T options to read null-terminated names
              verbatim (disables special handling of names that start with a

              See also --verbatim-files-from.

       -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.

              Stay in local file system when creating archive.

       -P, --absolute-names
              Don't strip leading slashes from file names when creating ar‐

              Recurse into directories (default).

              Backup before removal, override usual suffix.  Default suffix
              is ~, unless overridden by environment variable SIM‐

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

              Unless specified otherwise, the FILE must contain a list of
              names separated by ASCII LF (i.e. one name per line).  The
              names read are handled the same way as command line arguments.
              They undergo quote removal and word splitting, and any string
              that starts with a - is handled as tar command line option.

              If this behavior is undesirable, it can be turned off using
              the --verbatim-files-from option.

              The --null option instructs tar that the names in FILE are
              separated by ASCII NUL character, instead of LF.  It is useful
              if the list is generated by find(1) -print0 predicate.

              Unquote file or member names (default).

              Treat each line obtained from a file list as a file name, even
              if it starts with a dash.  File lists are supplied with the
              --files-from (-T) option.  The default behavior is to handle
              names supplied in file lists as if they were typed in the com‐
              mand line, i.e. any names starting with a dash are treated as
              tar options.  The --verbatim-files-from option disables this

              This option affects all --files-from options that occur after
              it in the command line.  Its effect is reverted by the
              --no-verbatim-files-from} option.

              This option is implied by the --null option.

              See also --add-file.

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

   File name transformations
              Strip NUMBER leading components from file names on extraction.

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

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

              Patterns match file name start.

              Ignore case.

              Patterns match after any / (default for exclusion).

              Case sensitive matching (default).

              Verbatim string matching.

              Wildcards do not match /.

              Use wildcards (default for exclusion).

              Wildcards match / (default for exclusion).

   Informative output
              Display progress messages every Nth record (default 10).

              Run ACTION on each checkpoint.

              Only set time when the file is more recent than what was given
              with --mtime.

              Print file time to its full resolution.

              Send verbose output to FILE.

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

              Disable quoting for characters from STRING.

              Additionally quote characters from STRING.

              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.

              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.

              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.

              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.

                     "%s: file name read contains nul character"

                     "A lone zero block at %s"

              Keywords applicable for tar --create:

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

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

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

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

                     "%s: file is unchanged; not dumped"

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

                     "%s: File removed before we read it"

                     "%s: file changed as we read it"

              Keywords applicable for tar --extract:

                     "%s: skipping existing file"

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

                     "Extracting contiguous files as regular files"

                     "Attempting extraction of symbolic links as hard links"

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

                     "Current %s is newer or same age"

                     "Ignoring unknown extended header keyword '%s'"

                     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

                     "Record size = %lu blocks"

              Keywords controlling incremental extraction:

                     "%s: Directory has been renamed from %s"
                     "%s: Directory has been renamed"

                     "%s: Directory is new"

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

                     "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         top

       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

       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         top

       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

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


BUG REPORTS         top

       Report bugs to <>.

COPYRIGHT         top

       Copyright © 2013 Free Software Foundation, Inc.
       License GPLv3+: GNU GPL version 3 or later
       This  is  free  software: you are free to change and redistribute it.
       There is NO WARRANTY, to the extent permitted by law.

COLOPHON         top

       This page is part of the tar (an archiver program) project.
       Information about the project can be found at 
       ⟨⟩.  If you have a bug report for
       this manual page, see ⟨⟩.
       This page was obtained from the project's upstream Git repository 
       ⟨git://⟩ on 2016-10-04.  If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail

TAR                            March 23, 2016                         TAR(1)