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<p valign="top">BSDTAR(1) FreeBSD General Commands Manual
BSDTAR(1)</p>
<p style="margin-top: 1em" valign="top"><b>NAME</b></p>
<p style="margin-left:8%;"><b>tar</b> — manipulate
tape archives</p>
<p style="margin-top: 1em" valign="top"><b>SYNOPSIS</b></p>
<p style="margin-left:14%;"><b>tar</b>
[<i>bundled-flags </i>⟨</p>
<p valign="top">args ⟩] [⟨ <i><br>
file</i> ⟩ | ⟨ <i><br>
pattern</i> ⟩ ...]</p>
<p style="margin-left:14%;"><b>tar</b> {<b>−c</b>}
[<i>options</i>]
[<i>files </i>| <i>directories</i>] <b><br>
tar</b> {<b>−r </b>| <b>−u</b>}
<b>−f</b> <i>archive-file</i> [<i>options</i>]
[<i>files </i>| <i>directories</i>] <b><br>
tar</b> {<b>−t </b>| <b>−x</b>}
[<i>options</i>] [<i>patterns</i>]</p>
<p style="margin-top: 1em" valign="top"><b>DESCRIPTION</b></p>
<p style="margin-left:8%;"><b>tar</b> creates and
manipulates streaming archive files. This implementation can
extract from tar, pax, cpio, zip, jar, ar, and ISO 9660
cdrom images and can create tar, pax, cpio, ar, and shar
archives.</p>
<p style="margin-left:8%; margin-top: 1em">The first
synopsis form shows a ‘‘bundled’’
option word. This usage is provided for compatibility with
historical implementations. See COMPATIBILITY below for
details.</p>
<p style="margin-left:8%; margin-top: 1em">The other
synopsis forms show the preferred usage. The first option to
<b>tar</b> is a mode indicator from the following list:</p>
<p valign="top"><b>−c</b></p>
<p style="margin-left:20%; margin-top: 1em">Create a new
archive containing the specified items.</p>
<p valign="top"><b>−r</b></p>
<p style="margin-left:20%; margin-top: 1em">Like
<b>−c</b>, but new entries are appended to the
archive. Note that this only works on uncompressed archives
stored in regular files. The <b>−f</b> option is
required.</p>
<p valign="top"><b>−t</b></p>
<p style="margin-left:20%; margin-top: 1em">List archive
contents to stdout.</p>
<p valign="top"><b>−u</b></p>
<p style="margin-left:20%; margin-top: 1em">Like
<b>−r</b>, 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 <b>−f</b> option
is required.</p>
<p valign="top"><b>−x</b></p>
<p style="margin-left:20%; margin-top: 1em">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.</p>
<p style="margin-left:8%; margin-top: 1em">In
<b>−c</b>, <b>−r</b>, or <b>−u</b> 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.</p>
<p style="margin-left:8%; margin-top: 1em">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).</p>
<p style="margin-top: 1em" valign="top"><b>OPTIONS</b></p>
<p style="margin-left:8%;">Unless specifically stated
otherwise, options are applicable in all operating
modes.</p>
<p style="margin-top: 1em" valign="top"><b>@</b><i>archive</i></p>
<p style="margin-left:20%;">(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,</p>
<p style="margin-left:29%;"><b>tar −c −f</b>
<i>- newfile</i> <b>@</b><i>original.tar</i></p>
<p style="margin-left:20%;">writes a new archive to
standard output containing a file <i>newfile</i> and all of
the entries from <i>original.tar</i>. In contrast,</p>
<p style="margin-left:29%;"><b>tar −c −f</b>
<i>- newfile original.tar</i></p>
<p style="margin-left:20%;">creates a new archive with only
two entries. Similarly,</p>
<p style="margin-left:29%;"><b>tar −czf</b> <i>-</i>
<b>−-format pax @</b><i>-</i></p>
<p style="margin-left:20%;">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, <b>tar</b> can be used to convert
archives from one format to another.</p>
<p style="margin-top: 1em" valign="top"><b>−b</b>
<i>blocksize</i></p>
<p style="margin-left:20%;">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.</p>
<p style="margin-top: 1em" valign="top"><b>−C</b>
<i>directory</i></p>
<p style="margin-left:20%;">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.</p>
<p style="margin-top: 1em" valign="top"><b>−-check-links</b></p>
<p style="margin-left:20%;">(c and r modes only) Issue a
warning message unless all links to each file are
archived.</p>
<p style="margin-top: 1em" valign="top"><b>−-chroot</b></p>
<p style="margin-left:20%;">(x mode only) <b>chroot</b>()
to the current directory after processing any
<b>−C</b> options and before extracting any files.</p>
<p style="margin-top: 1em" valign="top"><b>−-exclude</b>
<i>pattern</i></p>
<p style="margin-left:20%;">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.</p>
<p style="margin-top: 1em" valign="top"><b>−-format</b>
<i>format</i></p>
<p style="margin-left:20%;">(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-supported 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.</p>
<p style="margin-top: 1em" valign="top"><b>−f</b>
<i>file</i></p>
<p style="margin-left:20%;">Read the archive from or write
the archive to the specified file. The filename can be
<i>-</i> for standard input or standard output. If not
specified, the default tape device will be used. (On
FreeBSD, the default tape device is <i>/dev/sa0</i>.)</p>
<p style="margin-top: 1em" valign="top"><b>−H</b></p>
<p style="margin-left:20%; margin-top: 1em">(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.</p>
<p style="margin-top: 1em" valign="top"><b>−h</b></p>
<p style="margin-left:20%; margin-top: 1em">(c and r mode
only) Synonym for <b>−L</b>.</p>
<p style="margin-top: 1em" valign="top"><b>−I</b></p>
<p style="margin-left:20%; margin-top: 1em">Synonym for
<b>−T</b>.</p>
<p style="margin-top: 1em" valign="top"><b>−-include</b>
<i>pattern</i></p>
<p style="margin-left:20%;">Process only files or
directories that match the specified pattern. Note that
exclusions specified with <b>−-exclude</b> take
precedence over inclusions. If no inclusions are explicitly
specified, all entries are processed by default. The
<b>−-include</b> option is especially useful when
filtering archives. For example, the command</p>
<p style="margin-left:29%;"><b>tar −c −f</b>
<i>new.tar</i> <b>−-include=’*foo*’
@</b><i>old.tgz</i></p>
<p style="margin-left:20%;">creates a new archive
<i>new.tar</i> containing only the entries from
<i>old.tgz</i> containing the string ‘foo’.</p>
<p style="margin-top: 1em" valign="top"><b>−j</b></p>
<p style="margin-left:20%; margin-top: 1em">(c mode only)
Compress the resulting archive with bzip2(1). In extract or
list modes, this option is ignored. Note that, unlike other
<b>tar</b> implementations, this implementation recognizes
bzip2 compression automatically when reading archives.</p>
<p style="margin-top: 1em" valign="top"><b>−k</b></p>
<p style="margin-left:20%; margin-top: 1em">(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.</p>
<p style="margin-top: 1em" valign="top"><b>−-keep-newer-files</b></p>
<p style="margin-left:20%;">(x mode only) Do not overwrite
existing files that are newer than the versions appearing in
the archive being extracted.</p>
<p style="margin-top: 1em" valign="top"><b>−L</b></p>
<p style="margin-left:20%; margin-top: 1em">(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.</p>
<p style="margin-top: 1em" valign="top"><b>−l</b></p>
<p style="margin-left:20%; margin-top: 1em">This is a
synonym for the <b>−-check-links</b> option.</p>
<p style="margin-top: 1em" valign="top"><b>−m</b></p>
<p style="margin-left:20%; margin-top: 1em">(x mode only)
Do not extract modification time. By default, the
modification time is set to the time stored in the
archive.</p>
<p style="margin-top: 1em" valign="top"><b>−n</b></p>
<p style="margin-left:20%; margin-top: 1em">(c, r, u modes
only) Do not recursively archive the contents of
directories.</p>
<p style="margin-top: 1em" valign="top"><b>−-newer</b>
<i>date</i></p>
<p style="margin-left:20%;">(c, r, u modes only) Only
include files and directories newer than the specified date.
This compares ctime entries.</p>
<p style="margin-top: 1em" valign="top"><b>−-newer-mtime</b>
<i>date</i></p>
<p style="margin-left:20%;">(c, r, u modes only) Like
<b>−-newer</b>, except it compares mtime entries
instead of ctime entries.</p>
<p style="margin-top: 1em" valign="top"><b>−-newer-than</b>
<i>file</i></p>
<p style="margin-left:20%;">(c, r, u modes only) Only
include files and directories newer than the specified file.
This compares ctime entries.</p>
<p style="margin-top: 1em" valign="top"><b>−-newer-mtime-than</b>
<i>file</i></p>
<p style="margin-left:20%;">(c, r, u modes only) Like
<b>−-newer-than</b>, except it compares mtime entries
instead of ctime entries.</p>
<p style="margin-top: 1em" valign="top"><b>−-nodump</b></p>
<p style="margin-left:20%;">(c and r modes only) Honor the
nodump file flag by skipping this file.</p>
<p style="margin-top: 1em" valign="top"><b>−-null</b></p>
<p style="margin-left:20%; margin-top: 1em">(use with
<b>−I</b>, <b>−T</b>, or <b>−X</b>)
Filenames or patterns are separated by null characters, not
by newlines. This is often used to read filenames output by
the <b>−print0</b> option to find(1).</p>
<p style="margin-top: 1em" valign="top"><b>−-numeric-owner</b></p>
<p style="margin-left:20%;">(x mode only) Ignore symbolic
user and group names when restoring archives to disk, only
numeric uid and gid values will be obeyed.</p>
<p style="margin-top: 1em" valign="top"><b>−O</b></p>
<p style="margin-left:20%; margin-top: 1em">(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.</p>
<p style="margin-top: 1em" valign="top"><b>−o</b></p>
<p style="margin-left:20%; margin-top: 1em">(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 <b>−p</b> is specified, 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.</p>
<p style="margin-top: 1em" valign="top"><b>−o</b></p>
<p style="margin-left:20%; margin-top: 1em">(c, r, u mode)
A synonym for <b>−-format</b> <i>ustar</i></p>
<p style="margin-top: 1em" valign="top"><b>−-one-file-system</b></p>
<p style="margin-left:20%;">(c, r, and u modes) Do not
cross mount points.</p>
<p style="margin-top: 1em" valign="top"><b>−-options</b>
<i>options</i></p>
<p style="margin-left:20%;">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:</p>
<p valign="top"><i>key=value</i></p>
<p style="margin-left:32%;">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.</p>
<p valign="top"><i>key</i></p>
<p style="margin-left:32%; margin-top: 1em">The key will be
enabled in every module that supports it. This is equivalent
to <i>key</i><b>=1</b>.</p>
<p valign="top"><i>!key</i></p>
<p style="margin-left:32%; margin-top: 1em">The key will be
disabled in every module that supports it.</p>
<p valign="top"><i>module:key=value</i>, <i>module:key</i>,
<i>module:!key</i></p>
<p style="margin-left:32%;">As above, but the corresponding
key and value will be provided only to modules whose name
matches <i>module</i>.</p>
<p style="margin-left:20%;">The currently supported modules
and keys are:</p>
<p valign="top"><b>iso9660:joliet</b></p>
<p style="margin-left:32%;">Support Joliet extensions. This
is enabled by default, use <b>!joliet</b> or
<b>iso9660:!joliet</b> to disable.</p>
<p valign="top"><b>iso9660:rockridge</b></p>
<p style="margin-left:32%;">Support Rock Ridge extensions.
This is enabled by default, use <b>!rockridge</b> or
<b>iso9660:!rockridge</b> to disable.</p>
<p valign="top"><b>gzip:compression-level</b></p>
<p style="margin-left:32%;">A decimal integer from 0 to 9
specifying the gzip compression level.</p>
<p valign="top"><b>xz:compression-level</b></p>
<p style="margin-left:32%;">A decimal integer from 0 to 9
specifying the xz compression level.</p>
<p valign="top"><b>mtree:</b><i>keyword</i></p>
<p style="margin-left:32%;">The mtree writer module allows
you to specify which mtree keywords will be included in the
output. Supported keywords include: <b>cksum</b>,
<b>device</b>, <b>flags</b>, <b>gid</b>, <b>gname</b>,
<b>indent</b>, <b>link</b>, <b>md5</b>, <b>mode</b>,
<b>nlink</b>, <b>rmd160</b>, <b>sha1</b>, <b>sha256</b>,
<b>sha384</b>, <b>sha512</b>, <b>size</b>, <b>time</b>,
<b>uid</b>, <b>uname</b>. The default is equivalent to:
‘‘device, flags, gid, gname, link, mode, nlink,
size, time, type, uid, uname’’.</p>
<p valign="top"><b>mtree:all</b></p>
<p style="margin-left:32%;">Enables all of the above
keywords. You can also use <b>mtree:!all</b> to disable all
keywords.</p>
<p valign="top"><b>mtree:use-set</b></p>
<p style="margin-left:32%;">Enable generation of
<b>/set</b> lines in the output.</p>
<p valign="top"><b>mtree:indent</b></p>
<p style="margin-left:32%;">Produce human-readable output
by indenting options and splitting lines to fit into 80
columns.</p>
<p valign="top"><b>zip:compression</b>=<i>type</i></p>
<p style="margin-left:32%;">Use <i>type</i> as compression
method. Supported values are store (uncompressed) and
deflate (gzip algorithm).</p>
<p style="margin-left:20%;">If a provided option is not
supported by any module, that is a fatal error.</p>
<p style="margin-top: 1em" valign="top"><b>−P</b></p>
<p style="margin-left:20%; margin-top: 1em">Preserve
pathnames. By default, absolute pathnames (those that begin
with a / character) have the leading slash removed both when
creating archives and extracting from them. Also, <b>tar</b>
will refuse to extract archive entries whose pathnames
contain <i>..</i> or whose target directory would be altered
by a symlink. This option suppresses these behaviors.</p>
<p style="margin-top: 1em" valign="top"><b>−p</b></p>
<p style="margin-left:20%; margin-top: 1em">(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. By default, newly-created files are owned by the
user running <b>tar</b>, the file mode is restored for
newly-created regular files, and all other types of entries
receive default permissions. If <b>tar</b> is being run by
root, the default is to restore the owner unless the
<b>−o</b> option is also specified.</p>
<p style="margin-top: 1em" valign="top"><b>−q</b>
(<b>−-fast-read</b>)</p>
<p style="margin-left:20%;">(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
overwrite earlier entries. This option is provided as a
performance optimization.</p>
<p style="margin-top: 1em" valign="top"><b>−S</b></p>
<p style="margin-left:20%; margin-top: 1em">(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 similiar to the conv=sparse option of
dd.</p>
<p style="margin-top: 1em" valign="top"><b>−-strip-components</b>
<i>count</i></p>
<p style="margin-left:20%;">(x mode only) Remove the
specified number of leading path elements. Pathnames with
fewer elements will be silently skipped. Note that the
pathname is edited after checking inclusion/exclusion
patterns but before security checks.</p>
<p style="margin-top: 1em" valign="top"><b>−s</b>
<i>pattern</i></p>
<p style="margin-left:20%;">Modify file or archive member
names according to <i>pattern</i>. The pattern has the
format <i>/old/new/</i>[gps] where <i>old</i> is a basic
regular expression, <i>new</i> is the replacement string of
the matched part, and the optional trailing letters modify
how the replacement is handled. If <i>old</i> is not
matched, the pattern is skipped. Within <i>new</i>, ~ is
substituted with the match, 1 to 9 with the content of the
corresponding captured group. The optional trailing g
specifies that matching should continue after the matched
part and stopped 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.</p>
<p style="margin-top: 1em" valign="top"><b>−T</b>
<i>filename</i></p>
<p style="margin-left:20%;">In x or t mode, <b>tar</b> will
read the list of names to be extracted from <i>filename</i>.
In c mode, <b>tar</b> will read names to be archived from
<i>filename</i>. 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 <b>−-null</b> is specified. Note that
<b>−-null</b> also disables the special handling of
lines containing ‘‘-C’’.</p>
<p style="margin-top: 1em" valign="top"><b>−U</b></p>
<p style="margin-left:20%; margin-top: 1em">(x mode only)
Unlink files before creating them. Without this option,
<b>tar</b> overwrites existing files, which preserves
existing hardlinks. With this option, existing hardlinks
will be broken, as will any symlink that would affect the
location of an extracted file.</p>
<p style="margin-top: 1em" valign="top"><b>−-use-compress-program</b>
<i>program</i></p>
<p style="margin-left:20%;">Pipe the input (in x or t mode)
or the output (in c mode) through <i>program</i> instead of
using the builtin compression support.</p>
<p style="margin-top: 1em" valign="top"><b>−v</b></p>
<p style="margin-left:20%; margin-top: 1em">Produce verbose
output. In create and extract modes, <b>tar</b> will list
each file name as it is read from or written to the archive.
In list mode, <b>tar</b> will produce output similar to that
of ls(1). Additional <b>−v</b> options will provide
additional detail.</p>
<p style="margin-top: 1em" valign="top"><b>−-version</b></p>
<p style="margin-left:20%;">Print version of <b>tar</b> and
<b>libarchive</b>, and exit.</p>
<p style="margin-top: 1em" valign="top"><b>−w</b></p>
<p style="margin-left:20%; margin-top: 1em">Ask for
confirmation for every action.</p>
<p style="margin-top: 1em" valign="top"><b>−X</b>
<i>filename</i></p>
<p style="margin-left:20%;">Read a list of exclusion
patterns from the specified file. See <b>−-exclude</b>
for more information about the handling of exclusions.</p>
<p style="margin-top: 1em" valign="top"><b>−y</b></p>
<p style="margin-left:20%; margin-top: 1em">(c mode only)
Compress the resulting archive with bzip2(1). In extract or
list modes, this option is ignored. Note that, unlike other
<b>tar</b> implementations, this implementation recognizes
bzip2 compression automatically when reading archives.</p>
<p style="margin-top: 1em" valign="top"><b>−z</b></p>
<p style="margin-left:20%; margin-top: 1em">(c mode only)
Compress the resulting archive with gzip(1). In extract or
list modes, this option is ignored. Note that, unlike other
<b>tar</b> implementations, this implementation recognizes
gzip compression automatically when reading archives.</p>
<p style="margin-top: 1em" valign="top"><b>−Z</b></p>
<p style="margin-left:20%; margin-top: 1em">(c mode only)
Compress the resulting archive with compress(1). In extract
or list modes, this option is ignored. Note that, unlike
other <b>tar</b> implementations, this implementation
recognizes compress compression automatically when reading
archives.</p>
<p style="margin-top: 1em" valign="top"><b>ENVIRONMENT</b></p>
<p style="margin-left:8%;">The following environment
variables affect the execution of <b>tar</b>:</p>
<p style="margin-top: 1em" valign="top">LANG</p>
<p style="margin-left:25%; margin-top: 1em">The locale to
use. See environ(7) for more information.</p>
<p style="margin-top: 1em" valign="top">TAPE</p>
<p style="margin-left:25%; margin-top: 1em">The default
tape device. The <b>−f</b> option overrides this.</p>
<p style="margin-top: 1em" valign="top">TZ</p>
<p style="margin-left:25%; margin-top: 1em">The timezone to
use when displaying dates. See environ(7) for more
information.</p>
<p style="margin-top: 1em" valign="top"><b>FILES</b> <br>
/dev/sa0</p>
<p style="margin-left:25%; margin-top: 1em">The default
tape device, if not overridden by the TAPE environment
variable or the <b>−f</b> option.</p>
<p style="margin-top: 1em" valign="top"><b>EXIT
STATUS</b></p>
<p style="margin-left:8%;">The <b>tar</b> utility
exits 0 on success, and >0 if an error
occurs.</p>
<p style="margin-top: 1em" valign="top"><b>EXAMPLES</b></p>
<p style="margin-left:8%;">The following creates a new
archive called <i>file.tar.gz</i> that contains two files
<i>source.c</i> and <i>source.h</i>:</p>
<p style="margin-left:17%;"><b>tar −czf</b>
<i>file.tar.gz source.c source.h</i></p>
<p style="margin-left:8%; margin-top: 1em">To view a
detailed table of contents for this archive:</p>
<p style="margin-left:17%;"><b>tar −tvf</b>
<i>file.tar.gz</i></p>
<p style="margin-left:8%; margin-top: 1em">To extract all
entries from the archive on the default tape drive:</p>
<p style="margin-left:17%;"><b>tar −x</b></p>
<p style="margin-left:8%; margin-top: 1em">To examine the
contents of an ISO 9660 cdrom image:</p>
<p style="margin-left:17%;"><b>tar −tf</b>
<i>image.iso</i></p>
<p style="margin-left:8%; margin-top: 1em">To move file
hierarchies, invoke <b>tar</b> as</p>
<p style="margin-left:17%;"><b>tar −cf</b> <i>-</i>
<b>−C</b> <i>srcdir .</i> | <b>tar −xpf</b>
<i>-</i> <b>−C</b> <i>destdir</i></p>
<p style="margin-left:8%;">or more traditionally</p>
<p style="margin-left:17%;">cd srcdir ; <b>tar
−cf</b> <i>- .</i> | (<i>cd destdir ;</i> <b>tar
−xpf</b> <i>-</i>)</p>
<p style="margin-left:8%; margin-top: 1em">In create mode,
the list of files and directories to be archived can also
include directory change instructions of the form
<b>-C</b><i>foo/baz</i> and archive inclusions of the form
<b>@</b><i>archive-file</i>. For example, the command
line</p>
<p style="margin-left:17%;"><b>tar −c −f</b>
<i>new.tar foo1</i> <b>@</b><i>old.tgz</i> <b>-C</b><i>/tmp
foo2</i></p>
<p style="margin-left:8%;">will create a new archive
<i>new.tar</i>. <b>tar</b> will read the file <i>foo1</i>
from the current directory and add it to the output archive.
It will then read each entry from <i>old.tgz</i> and add
those entries to the output archive. Finally, it will switch
to the <i>/tmp</i> directory and add <i>foo2</i> to the
output archive.</p>
<p style="margin-left:8%; margin-top: 1em">An input file in
mtree(5) format can be used to create an output archive with
arbitrary ownership, permissions, or names that differ from
existing data on disk:</p>
<p style="margin-left:17%; margin-top: 1em">$ cat
input.mtree <br>
#mtree <br>
usr/bin uid=0 gid=0 mode=0755 type=dir <br>
usr/bin/ls uid=0 gid=0 mode=0755 type=file content=myls <br>
$ tar -cvf output.tar @input.mtree</p>
<p style="margin-left:8%; margin-top: 1em">The
<b>−-newer</b> and <b>−-newer-mtime</b> switches
accept a variety of common date and time specifications,
including ‘‘12 Mar 2005 7:14:29pm’’,
‘‘2005-03-12 19:14’’,
‘‘5 minutes ago’’, and
‘‘19:14 PST May 1’’.</p>
<p style="margin-left:8%; margin-top: 1em">The
<b>−-options</b> argument can be used to control
various details of archive generation or reading. For
example, you can generate mtree output which only contains
<b>type</b>, <b>time</b>, and <b>uid</b> keywords:</p>
<p style="margin-left:17%;"><b>tar −cf</b>
<i>file.tar</i> <b>−-format=mtree
−-options=’!all,type,time,uid’</b>
<i>dir</i></p>
<p style="margin-left:8%;">or you can set the compression
level used by gzip or xz compression:</p>
<p style="margin-left:17%;"><b>tar −czf</b>
<i>file.tar</i>
<b>−-options=’compression-level=9’</b>.</p>
<p style="margin-left:8%;">For more details, see the
explanation of the <b>archive_read_set_options</b>() and
<b>archive_write_set_options</b>() API calls that are
described in archive_read(3) and archive_write(3).</p>
<p style="margin-top: 1em" valign="top"><b>COMPATIBILITY</b></p>
<p style="margin-left:8%;">The bundled-arguments format is
supported for compatibility with historic implementations.
It consists of an initial word (with no leading - character)
in which each character indicates an option. Arguments
follow as separate words. The order of the arguments must
match the order of the corresponding characters in the
bundled command word. For example,</p>
<p style="margin-left:17%;"><b>tar tbf 32</b>
<i>file.tar</i></p>
<p style="margin-left:8%;">specifies three flags <b>t</b>,
<b>b</b>, and <b>f</b>. The <b>b</b> and <b>f</b> flags both
require arguments, so there must be two additional items on
the command line. The <i>32</i> is the argument to the
<b>b</b> flag, and <i>file.tar</i> is the argument to the
<b>f</b> flag.</p>
<p style="margin-left:8%; margin-top: 1em">The mode options
c, r, t, u, and x and the options b, f, l, m, o, v, and w
comply with SUSv2.</p>
<p style="margin-left:8%; margin-top: 1em">For maximum
portability, scripts that invoke <b>tar</b> should use the
bundled-argument format above, should limit themselves to
the <b>c</b>, <b>t</b>, and <b>x</b> modes, and the
<b>b</b>, <b>f</b>, <b>m</b>, <b>v</b>, and <b>w</b>
options.</p>
<p style="margin-left:8%; margin-top: 1em">Additional long
options are provided to improve compatibility with other tar
implementations.</p>
<p style="margin-top: 1em" valign="top"><b>SECURITY</b></p>
<p style="margin-left:8%;">Certain security issues are
common to many archiving programs, including <b>tar</b>. In
particular, carefully-crafted archives can request that
<b>tar</b> 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 happen. Although <b>tar</b> has
mechanisms to protect against each one, savvy users should
be aware of the implications:</p>
<p style="margin-top: 1em" valign="top"><b>•</b></p>
<p style="margin-left:20%;">Archive entries can have
absolute pathnames. By default, <b>tar</b> removes the
leading <i>/</i> character from filenames before restoring
them to guard against this problem.</p>
<p style="margin-top: 1em" valign="top"><b>•</b></p>
<p style="margin-left:20%;">Archive entries can have
pathnames that include <i>..</i> components. By default,
<b>tar</b> will not extract files containing <i>..</i>
components in their pathname.</p>
<p style="margin-top: 1em" valign="top"><b>•</b></p>
<p style="margin-left:20%;">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, <b>tar</b> 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
<b>−U</b> is specified, any intermediate symlink will
also be unconditionally removed. If neither <b>−U</b>
nor <b>−P</b> is specified, <b>tar</b> will refuse to
extract the entry.</p>
<p style="margin-left:8%;">To protect yourself, you should
be wary of any archives that come from untrusted sources.
You should examine the contents of an archive with</p>
<p style="margin-left:17%;"><b>tar −tf</b>
<i>filename</i></p>
<p style="margin-left:8%;">before extraction. You should
use the <b>−k</b> option to ensure that <b>tar</b>
will not overwrite any existing files or the <b>−U</b>
option to remove any pre-existing files. You should
generally not extract archives while running with super-user
privileges. Note that the <b>−P</b> option to
<b>tar</b> disables the security checks above and allows you
to extract an archive while preserving any absolute
pathnames, <i>..</i> components, or symlinks to other
directories.</p>
<p style="margin-top: 1em" valign="top"><b>SEE ALSO</b></p>
<p style="margin-left:8%;">bzip2(1), compress(1), cpio(1),
gzip(1), mt(1), pax(1), shar(1), libarchive(3),
libarchive-formats(5), tar(5)</p>
<p style="margin-top: 1em" valign="top"><b>STANDARDS</b></p>
<p style="margin-left:8%;">There is no current POSIX
standard for the tar command; it appeared in ISO/IEC
9945-1:1996 (‘‘POSIX.1’’) but was
dropped from IEEE Std 1003.1-2001
(‘‘POSIX.1’’). The options used by
this implementation were developed by surveying a number of
existing tar implementations as well as the old POSIX
specification for tar and the current POSIX specification
for pax.</p>
<p style="margin-left:8%; margin-top: 1em">The ustar and
pax interchange file formats are defined by IEEE Std
1003.1-2001 (‘‘POSIX.1’’) for the
pax command.</p>
<p style="margin-top: 1em" valign="top"><b>HISTORY</b></p>
<p style="margin-left:8%;">A <b>tar</b> 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
<b>pdtar</b> 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.</p>
<p style="margin-left:8%; margin-top: 1em">This is a
complete re-implementation based on the libarchive(3)
library.</p>
<p style="margin-top: 1em" valign="top"><b>BUGS</b></p>
<p style="margin-left:8%;">This program follows ISO/IEC
9945-1:1996 (‘‘POSIX.1’’) for the
definition of the <b>−l</b> option. Note that GNU tar
prior to version 1.15 treated <b>−l</b> as a synonym
for the <b>−-one-file-system</b> option.</p>
<p style="margin-left:8%; margin-top: 1em">The
<b>−C</b> <i>dir</i> option may differ from historic
implementations.</p>
<p style="margin-left:8%; margin-top: 1em">All archive
output is written in correctly-sized blocks, even if the
output is being compressed. Whether or not the last output
block is padded to a full block size varies depending on the
format and the output device. For tar and cpio formats, the
last block of output is padded to a full block size if the
output is being written to standard output or to a character
or block device such as a tape drive. If the output is being
written to a regular file, the last block will not be
padded. Many compressors, including gzip(1) and bzip2(1),
complain about the null padding when decompressing an
archive created by <b>tar</b>, although they still extract
it correctly.</p>
<p style="margin-left:8%; margin-top: 1em">The compression
and decompression is implemented internally, so there may be
insignificant differences between the compressed output
generated by</p>
<p style="margin-left:17%;"><b>tar −czf</b> <i>-
file</i></p>
<p style="margin-left:8%;">and that generated by</p>
<p style="margin-left:17%;"><b>tar −cf</b> <i>-
file</i> | <b>gzip</b></p>
<p style="margin-left:8%; margin-top: 1em">The default
should be to read and write archives to the standard I/O
paths, but tradition (and POSIX) dictates otherwise.</p>
<p style="margin-left:8%; margin-top: 1em">The <b>r</b> and
<b>u</b> modes require that the archive be uncompressed and
located in a regular file on disk. Other archives can be
modified using <b>c</b> mode with the <i>@archive-file</i>
extension.</p>
<p style="margin-left:8%; margin-top: 1em">To archive a
file called <i>@foo</i> or <i>-foo</i> you must specify it
as <i>./@foo</i> or <i>./-foo</i>, respectively.</p>
<p style="margin-left:8%; margin-top: 1em">In create mode,
a leading <i>./</i> is always removed. A leading <i>/</i> is
stripped unless the <b>−P</b> option is specified.</p>
<p style="margin-left:8%; margin-top: 1em">There needs to
be better support for file selection on both create and
extract.</p>
<p style="margin-left:8%; margin-top: 1em">There is not yet
any support for multi-volume archives or for archiving
sparse files.</p>
<p style="margin-left:8%; margin-top: 1em">Converting
between dissimilar archive formats (such as tar and cpio)
using the <b>@</b><i>-</i> convention can cause hard link
information to be lost. (This is a consequence of the
incompatible ways that different archive formats store
hardlink information.)</p>
<p style="margin-left:8%; margin-top: 1em">There are
alternative long options for many of the short options that
are deliberately not documented.</p>
<p style="margin-left:8%; margin-top: 1em">FreeBSD 8.0
Oct 12, 2009 FreeBSD 8.0</p>
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