Unix/Linux Go Back    


CentOS 7.0 - man page for bsdtar (centos section 1)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


TAR(1)				   BSD General Commands Manual				   TAR(1)

NAME
     tar -- manipulate tape archives

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

DESCRIPTION
     tar creates and manipulates streaming archive files.  This implementation can extract from
     tar, pax, cpio, zip, jar, ar, xar, rpm, 7-zip, and ISO 9660 cdrom images and can create tar,
     pax, cpio, ar, zip, 7-zip, and shar archives.

     The first synopsis form shows a ``bundled'' option word.  This usage is provided for compat-
     ibility with historical implementations.  See COMPATIBILITY below for details.

     The other synopsis forms show the preferred usage.  The first option to tar is a mode indi-
     cator from the following list:
     -c      Create a new archive containing the specified items.  The long option form is
	     --create.
     -r      Like -c, but new entries are appended to the archive.  Note that this only works on
	     uncompressed archives stored in regular files.  The -f option is required.  The long
	     option form is --append.
     -t      List archive contents to stdout.  The long option form is --list.
     -u      Like -r, but new entries are added only if they have a modification date newer than
	     the corresponding entry in the archive.  Note that this only works on uncompressed
	     archives stored in regular files.	The -f option is required.  The long form is
	     --update.
     -x      Extract to disk from the archive.	If a file with the same name appears more than
	     once in the archive, each copy will be extracted, with later copies overwriting
	     (replacing) earlier copies.  The long option form is --extract.

     In -c, -r, or -u mode, each specified file or directory is added to the archive in the order
     specified on the command line.  By default, the contents of each directory are also
     archived.

     In extract or list mode, the entire command line is read and parsed before the archive is
     opened.  The 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(1).

OPTIONS
     Unless specifically stated otherwise, options are applicable in all operating modes.

     @archive
	     (c and r mode only) The specified archive is opened and the entries in it will be
	     appended to the current archive.  As a simple example,
		   tar -c -f - newfile @original.tar
	     writes a new archive to standard output containing a file newfile and all of the
	     entries from original.tar.  In contrast,
		   tar -c -f - newfile original.tar
	     creates a new archive with only two entries.  Similarly,
		   tar -czf - --format pax @-
	     reads an archive from standard input (whose format will be determined automatically)
	     and converts it into a gzip-compressed pax-format archive on stdout.  In this way,
	     tar can be used to convert archives from one format to another.

     -a, --auto-compress
	     (c mode only) Use the archive suffix to decide a set of the format and the compres-
	     sions.  As a simple example,
		   tar -a -cf archive.tgz source.c source.h
	     creates a new archive with restricted pax format and gzip compression,
		   tar -a -cf archive.tar.bz2.uu source.c source.h
	     creates a new archive with restricted pax format and bzip2 compression and uuencode
	     compression,
		   tar -a -cf archive.zip source.c source.h
	     creates a new archive with zip format,
		   tar -a -jcf archive.tgz source.c source.h
	     ignores the ``-j'' option, and creates a new archive with restricted pax format and
	     gzip compression,
		   tar -a -jcf archive.xxx source.c source.h
	     if it is unknown suffix or no suffix, creates a new archive with restricted pax for-
	     mat and bzip2 compression.

     -B, --read-full-blocks
	     Ignored for compatibility with other tar(1) implementations.

     -b blocksize, --block-size blocksize
	     Specify the block size, in 512-byte records, for tape drive I/O.  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.

     -C directory, --cd directory, --directory directory
	     In c and r mode, this changes the directory before adding the following files.  In x
	     mode, change directories after opening the archive but before extracting entries
	     from the archive.

     --chroot
	     (x mode only) chroot() to the current directory after processing any -C options and
	     before extracting any files.

     --disable-copyfile
	     Mac OS X specific.  Disable the use of copyfile(3).

     --exclude pattern
	     Do not process files or directories that match the specified pattern.  Note that
	     exclusions take precedence over patterns or filenames specified on the command line.

     --format format
	     (c, r, u mode only) Use the specified format for the created archive.  Supported
	     formats include ``cpio'', ``pax'', ``shar'', and ``ustar''.  Other formats may also
	     be supported; see libarchive-formats(5) for more information about currently-sup-
	     ported formats.  In r and u modes, when extending an existing archive, the format
	     specified here must be compatible with the format of the existing archive on disk.

     -f file, --file file
	     Read the archive from or write the archive to the specified file.	The filename can
	     be - for standard input or standard output.  The default varies by system; on
	     FreeBSD, the default is /dev/sa0; on Linux, the default is /dev/st0.

     --gid id
	     Use the provided group id number.	On extract, this overrides the group id in the
	     archive; the group name in the archive will be ignored.  On create, this overrides
	     the group id read from disk; if --gname is not also specified, the group name will
	     be set to match the group id.

     --gname name
	     Use the provided group name.  On extract, this overrides the group name in the ar-
	     chive; if the provided group name does not exist on the system, the group id (from
	     the archive or from the --gid option) will be used instead.  On create, this sets
	     the group name that will be stored in the archive; the name will not be verified
	     against the system group database.

     -H      (c and r mode only) Symbolic links named on the command line will be followed; the
	     target of the link will be archived, not the link itself.

     -h      (c and r mode only) Synonym for -L.

     -I      Synonym for -T.

     --help  Show usage.

     --hfsCompression
	     (x mode only) Mac OS X specific(v10.6 or later). Compress extracted regular files
	     with HFS+ compression.

     --include pattern
	     Process only files or directories that match the specified pattern.  Note that
	     exclusions specified with --exclude take precedence over inclusions.  If no inclu-
	     sions are explicitly specified, all entries are processed by default.  The --include
	     option is especially useful when filtering archives.  For example, the command
		   tar -c -f new.tar --include='*foo*' @old.tgz
	     creates a new archive new.tar containing only the entries from old.tgz containing
	     the string 'foo'.

     -J, --xz
	     (c mode only) Compress the resulting archive with xz(1).  In extract or list modes,
	     this option is ignored.  Note that, unlike other tar implementations, this implemen-
	     tation recognizes XZ compression automatically when reading archives.

     -j, --bzip, --bzip2, --bunzip2
	     (c mode only) Compress the resulting archive with bzip2(1).  In extract or list
	     modes, this option is ignored.  Note that, unlike other tar implementations, this
	     implementation recognizes bzip2 compression automatically when reading archives.

     -k, --keep-old-files
	     (x mode only) Do not overwrite existing files.  In particular, if a file appears
	     more than once in an archive, later copies will not overwrite earlier copies.

     --keep-newer-files
	     (x mode only) Do not overwrite existing files that are newer than the versions
	     appearing in the archive being extracted.

     -L, --dereference
	     (c and r mode only) All symbolic links will be followed.  Normally, symbolic links
	     are archived as such.  With this option, the target of the link will be archived
	     instead.

     -l, --check-links
	     (c and r modes only) Issue a warning message unless all links to each file are
	     archived.

     --lrzip
	     (c mode only) Compress the resulting archive with lrzip(1).  In extract or list
	     modes, this option is ignored.

     --lzma  (c mode only) Compress the resulting archive with the original LZMA algorithm.  Use
	     of this option is discouraged and new archives should be created with --xz instead.
	     Note that, unlike other tar implementations, this implementation recognizes LZMA
	     compression automatically when reading archives.

     --lzop  (c mode only) Compress the resulting archive with lzop(1).  In extract or list
	     modes, this option is ignored.

     -m, --modification-time
	     (x mode only) Do not extract modification time.  By default, the modification time
	     is set to the time stored in the archive.

     -n, --norecurse, --no-recursion
	     (c, r, u modes only) Do not recursively archive the contents of directories.

     --newer date
	     (c, r, u modes only) Only include files and directories newer than the specified
	     date.  This compares ctime entries.

     --newer-mtime date
	     (c, r, u modes only) Like --newer, except it compares mtime entries instead of ctime
	     entries.

     --newer-than file
	     (c, r, u modes only) Only include files and directories newer than the specified
	     file.  This compares ctime entries.

     --newer-mtime-than file
	     (c, r, u modes only) Like --newer-than, except it compares mtime entries instead of
	     ctime entries.

     --nodump
	     (c and r modes only) Honor the nodump file flag by skipping this file.

     --nopreserveHFSCompression
	     (x mode only) Mac OS X specific(v10.6 or later). Do not compress extracted regular
	     files which were compressed with HFS+ compression before archived.  By default, com-
	     press the regular files again with HFS+ compression.

     --null  (use with -I or -T) Filenames or patterns are separated by null characters, not by
	     newlines.	This is often used to read filenames output by the -print0 option to
	     find(1).

     --no-same-owner
	     (x mode only) Do not extract owner and group IDs.	This is the reverse of
	     --same-owner and the default behavior if tar is run as non-root.

     --no-same-permissions
	     (x mode only) Do not extract full permissions (SGID, SUID, sticky bit, ACLs,
	     extended attributes or extended file flags).  This is the reverse of -p and the
	     default behavior if tar is run as non-root.

     --numeric-owner
	     This is equivalent to --uname "" --gname "".  On extract, it causes user and group
	     names in the archive to be ignored in favor of the numeric user and group ids.  On
	     create, it causes user and group names to not be stored in the archive.

     -O, --to-stdout
	     (x, t modes only) In extract (-x) mode, files will be written to standard out rather
	     than being extracted to disk.  In list (-t) mode, the file listing will be written
	     to stderr rather than the usual stdout.

     -o      (x mode) Use the user and group of the user running the program rather than those
	     specified in the archive.	Note that this has no significance unless -p is speci-
	     fied, and the program is being run by the root user.  In this case, the file modes
	     and flags from the archive will be restored, but ACLs or owner information in the
	     archive will be discarded.

     -o      (c, r, u mode) A synonym for --format ustar

     --older date
	     (c, r, u modes only) Only include files and directories older than the specified
	     date.  This compares ctime entries.

     --older-mtime date
	     (c, r, u modes only) Like --older, except it compares mtime entries instead of ctime
	     entries.

     --older-than file
	     (c, r, u modes only) Only include files and directories older than the specified
	     file.  This compares ctime entries.

     --older-mtime-than file
	     (c, r, u modes only) Like --older-than, except it compares mtime entries instead of
	     ctime entries.

     --one-file-system
	     (c, r, and u modes) Do not cross mount points.

     --options options
	     Select optional behaviors for particular modules.	The argument is a text string
	     containing comma-separated keywords and values.  These are passed to the modules
	     that handle particular formats to control how those formats will behave.  Each
	     option has one of the following forms:
	     key=value
		     The key will be set to the specified value in every module that supports it.
		     Modules that do not support this key will ignore it.
	     key     The key will be enabled in every module that supports it.	This is equiva-
		     lent to key=1.
	     !key    The key will be disabled in every module that supports it.
	     module:key=value, module:key, module:!key
		     As above, but the corresponding key and value will be provided only to mod-
		     ules whose name matches module.
	     The currently supported modules and keys are:
	     iso9660:joliet
		     Support Joliet extensions.  This is enabled by default, use !joliet or
		     iso9660:!joliet to disable.
	     iso9660:rockridge
		     Support Rock Ridge extensions.  This is enabled by default, use !rockridge
		     or iso9660:!rockridge to disable.
	     gzip:compression-level
		     A decimal integer from 1 to 9 specifying the gzip compression level.
	     gzip:timestamp
		     Store timestamp. This is enabled by default, use !timestamp or
		     gzip:!timestamp to disable.
	     lrzip:compression=type
		     Use type as compression method.  Supported values are bzip2, gzip, lzo
		     (ultra fast), and zpaq (best, extremely slow).
	     lrzip:compression-level
		     A decimal integer from 1 to 9 specifying the lrzip compression level.
	     lzop:compression-level
		     A decimal integer from 1 to 9 specifying the lzop compression level.
	     xz:compression-level
		     A decimal integer from 0 to 9 specifying the xz compression level.
	     mtree:keyword
		     The mtree writer module allows you to specify which mtree keywords will be
		     included in the output.  Supported keywords include: cksum, device, flags,
		     gid, gname, indent, link, md5, mode, nlink, rmd160, sha1, sha256, sha384,
		     sha512, size, time, uid, uname.  The default is equivalent to: ``device,
		     flags, gid, gname, link, mode, nlink, size, time, type, uid, uname''.
	     mtree:all
		     Enables all of the above keywords.  You can also use 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.
	     zip:compression=type
		     Use type as compression method.  Supported values are store (uncompressed)
		     and deflate (gzip algorithm).
	     If a provided option is not supported by any module, that is a fatal error.

     -P, --absolute-paths
	     Preserve pathnames.  By default, absolute pathnames (those that begin with a / char-
	     acter) have the leading slash removed both when creating archives and extracting
	     from them.  Also, tar will refuse to extract archive entries whose pathnames contain
	     .. or whose target directory would be altered by a symlink.  This option suppresses
	     these behaviors.

     -p, --insecure, --preserve-permissions
	     (x mode only) Preserve file permissions.  Attempt to restore the full permissions,
	     including owner, file modes, file flags and ACLs, if available, for each item
	     extracted from the archive.  This is the default, if tar is being run by root and
	     can be overridden by also specifying --no-same-owner and --no-same-permissions.

     --posix
	     (c, r, u mode only) Synonym for --format pax

     -q, --fast-read
	     (x and t mode only) Extract or list only the first archive entry that matches each
	     pattern or filename operand.  Exit as soon as each specified pattern or filename has
	     been matched.  By default, the archive is always read to the very end, since there
	     can be multiple entries with the same name and, by convention, later entries over-
	     write earlier entries.  This option is provided as a performance optimization.

     -S      (x mode only) Extract files as sparse files.  For every block on disk, check first
	     if it contains only NULL bytes and seek over it otherwise.  This works similar to
	     the conv=sparse option of dd.

     -s pattern
	     Modify file or archive member names according to pattern.	The pattern has the for-
	     mat /old/new/[ghHprRsS] where old is a basic regular expression, new is the replace-
	     ment string of the matched part, and the optional trailing letters modify how the
	     replacement is handled.  If old is not matched, the pattern is skipped.  Within new,
	     ~ is substituted with the match, \1 to \9 with the content of the corresponding cap-
	     tured group.  The optional trailing g specifies that matching should continue after
	     the matched part and stop on the first unmatched pattern.	The optional trailing s
	     specifies that the pattern applies to the value of symbolic links.  The optional
	     trailing p specifies that after a successful substitution the original path name and
	     the new path name should be printed to standard error.  Optional trailing H, R, or S
	     characters suppress substitutions for hardlink targets, regular filenames, or sym-
	     link targets, respectively.  Optional trailing h, r, or s characters enable substi-
	     tutions for hardlink targets, regular filenames, or symlink targets, respectively.
	     The default is hrs which applies substitutions to all names.  In particular, it is
	     never necessary to specify h, r, or s.

     --same-owner
	     (x mode only) Extract owner and group IDs.  This is the reverse of --no-same-owner
	     and the default behavior if tar is run as root.

     --strip-components count
	     Remove the specified number of leading path elements.  Pathnames with fewer elements
	     will be silently skipped.	Note that the pathname is edited after checking inclu-
	     sion/exclusion patterns but before security checks.

     -T filename, --files-from filename
	     In x or t mode, tar will read the list of names to be extracted from filename.  In c
	     mode, tar will read names to be archived from filename.  The special name ``-C'' on
	     a line by itself will cause the current directory to be changed to the directory
	     specified on the following line.  Names are terminated by newlines unless --null is
	     specified.  Note that --null also disables the special handling of lines containing
	     ``-C''.  Note:  If you are generating lists of files using find(1), you probably
	     want to use -n as well.

     --totals
	     (c, r, u mode only) After archiving all files, print a summary to stderr.

     -U, --unlink, --unlink-first
	     (x mode only) Unlink files before creating them.  This can be a minor performance
	     optimization if most files already exist, but can make things slower if most files
	     do not already exist.  This flag also causes tar to remove intervening directory
	     symlinks instead of reporting an error.  See the SECURITY section below for more
	     details.

     --uid id
	     Use the provided user id number and ignore the user name from the archive.  On cre-
	     ate, if --uname is not also specified, the user name will be set to match the user
	     id.

     --uname name
	     Use the provided user name.  On extract, this overrides the user name in the ar-
	     chive; if the provided user name does not exist on the system, it will be ignored
	     and the user id (from the archive or from the --uid option) will be used instead.
	     On create, this sets the user name that will be stored in the archive; the name is
	     not verified against the system user database.

     --use-compress-program program
	     Pipe the input (in x or t mode) or the output (in c mode) through program instead of
	     using the builtin compression support.

     -v, --verbose
	     Produce verbose output.  In create and extract modes, tar will list each file name
	     as it is read from or written to the archive.  In list mode, tar will produce output
	     similar to that of ls(1).	Additional -v options will provide additional detail.

     --version
	     Print version of tar and libarchive, and exit.

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

     -X filename, --exclude-from filename
	     Read a list of exclusion patterns from the specified file.  See --exclude for more
	     information about the handling of exclusions.

     -y      (c mode only) Compress the resulting archive with bzip2(1).  In extract or list
	     modes, this option is ignored.  Note that, unlike other tar implementations, this
	     implementation recognizes bzip2 compression automatically when reading archives.

     -Z, --compress, --uncompress
	     (c mode only) Compress the resulting archive with compress(1).  In extract or list
	     modes, this option is ignored.  Note that, unlike other tar implementations, this
	     implementation recognizes compress compression automatically when reading archives.

     -z, --gunzip, --gzip
	     (c mode only) Compress the resulting archive with gzip(1).  In extract or list
	     modes, this option is ignored.  Note that, unlike other tar implementations, this
	     implementation recognizes gzip compression automatically when reading archives.

ENVIRONMENT
     The following environment variables affect the execution of tar:

     TAR_READER_OPTIONS
		The default options for format readers and compression readers.  The --options
		option overrides this.

     TAR_WRITER_OPTIONS
		The default options for format writers and compression writers.  The --options
		option overrides this.

     LANG	The locale to use.  See environ(7) for more information.

     TAPE	The default device.  The -f option overrides this.  Please see the description of
		the -f option above for more details.

     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 extract all entries from the archive on the default tape drive:
	   tar -x

     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 a new archive 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(5) format can be used to create an output archive with arbitrary own-
     ership, 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

     The --newer and --newer-mtime switches accept a variety of common date and time specifica-
     tions, including ``12 Mar 2005 7:14:29pm'', ``2005-03-12 19:14'', ``5 minutes ago'', and
     ``19:14 PST May 1''.

     The --options argument can be used to control various details of archive generation or read-
     ing.  For example, you can generate mtree output which only contains type, time, and uid
     keywords:
	   tar -cf file.tar --format=mtree --options='!all,type,time,uid' dir
     or you can set the compression level used by gzip or xz compression:
	   tar -czf file.tar --options='compression-level=9'.
     For more details, see the explanation of the archive_read_set_options() and
     archive_write_set_options() API calls that are described in archive_read(3) and
     archive_write(3).

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 indi-
     cates 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 implementa-
     tions.

SECURITY
     Certain security issues are common to many archiving programs, including tar.  In particu-
     lar, carefully-crafted archives can request that tar extract files to locations outside of
     the target directory.  This can potentially be used to cause unwitting users to overwrite
     files they did not intend to overwrite.  If the archive is being extracted by the superuser,
     any file on the system can potentially be overwritten.  There are three ways this can hap-
     pen.  Although tar has mechanisms to protect against each one, savvy users should be aware
     of the implications:

     o	     Archive entries can have absolute pathnames.  By default, tar removes the leading /
	     character from filenames before restoring them to guard against this problem.

     o	     Archive entries can have pathnames that include .. components.  By default, tar will
	     not extract files containing .. components in their pathname.

     o	     Archive entries can exploit symbolic links to restore files to other directories.
	     An archive can restore a symbolic link to another directory, then use that link to
	     restore a file into that directory.  To guard against this, tar checks each
	     extracted path for symlinks.  If the final path element is a symlink, it will be
	     removed and replaced with the archive entry.  If -U is specified, any intermediate
	     symlink will also be unconditionally removed.  If neither -U nor -P is specified,
	     tar will refuse to extract the entry.
     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.  You should use the -k option to ensure that tar will not overwrite any
     existing files or the -U option to remove any pre-existing files.	You should generally not
     extract archives while running with super-user privileges.  Note that the -P option to tar
     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), xz(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 sup-
     ported by this implementation were developed by surveying a number of existing tar implemen-
     tations 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.

HISTORY
     A tar command appeared in Seventh Edition Unix, which was released in January, 1979.  There
     have been numerous other implementations, many of which extended the file format.	John
     Gilmore's pdtar public-domain implementation (circa November, 1987) was quite influential,
     and formed the basis of GNU tar.  GNU tar was included as the standard system tar in FreeBSD
     beginning with FreeBSD 1.0.

     This is a complete re-implementation based on the libarchive(3) library.  It was first
     released with FreeBSD 5.4 in May, 2005.

BUGS
     This program follows ISO/IEC 9945-1:1996 (``POSIX.1'') for the definition of the -l option.
     Note that 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 com-
     pressed.  Whether or not the last output block is padded to a full block size varies depend-
     ing 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.)

BSD					 November 1, 2012				      BSD
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 11:48 PM.