MirBSD manpage: tar(1)
TAR(1) BSD Reference Manual TAR(1)
NAME
tar - tape archiver
SYNOPSIS
tar {crtux}[014578abefHhJjLmOoPpqsvwXZz] [blocking-factor | archive |
replstr] [-C directory] [-I file] [file ...]
tar {-crtux} [-014578aeHhJjLmOoPpqvwXZz] [-b blocking-factor]
[-C directory] [-D format-options] [-f archive] [-I file] [-M flag]
[-s replstr] [file ...]
DESCRIPTION
The tar command creates, adds files to, or extracts files from an archive
file in "tar" (strictly speaking, ustar) format. A tar archive is often
stored on a magnetic tape, but can be stored equally well on a floppy,
CD-ROM, or in a regular disk file.
In the first (legacy) form, all option flags except for -C and -I must be
contained within the first argument to tar and must not be prefixed by a
hyphen ('-'). Option arguments, if any, are processed as subsequent argu-
ments to tar and are processed in the order in which their corresponding
option flags have been presented on the command line.
In the second and preferred form, option flags may be given in any order
and are immediately followed by their corresponding option argument
values.
One of the following flags must be present:
-c Create new archive, or overwrite an existing archive, adding the
specified files to it.
-r Append the named new files to existing archive. Note that this
will only work on media on which an end-of-file mark can be
overwritten.
-t List contents of archive. If any files are named on the command
line, only those files will be listed. The file arguments may be
specified as glob patterns (see glob(7) for more information), in
which case tar will list all archive members that match each pat-
tern.
-u Alias for -r.
-x Extract files from archive. If any files are named on the command
line, only those files will be extracted from the archive. The
file arguments may be specified as glob patterns (see glob(7) for
more information), in which case tar will extract all archive
members that match each pattern.
If more than one copy of a file exists in the archive, later
copies will overwrite earlier copies during extraction. The file
mode and modification time are preserved if possible. The file
mode is subject to modification by the umask(2).
In addition to the flags mentioned above, any of the following flags may
be used:
-a Guess the compression utility based on the archive filename. Ina-
bility to guess will result in quietly not using any compression.
This option only exists for semi-compatibility with GNU tar; it
is strongly recommended to archive to stdout and pipe into an
external compression utility with appropriate arguments instead:
tar -cf - foo | xz -2e >foo.txz
-b blocking-factor
Set blocking factor to use for the archive. tar uses 512-byte
blocks. The default is 20, the maximum is 126. Archives with a
blocking factor larger than 63 violate the POSIX standard and
will not be portable to all systems.
-C directory
This is a positional argument which sets the working directory
for the following files. When extracting, files will be extracted
into the specified directory; when creating, the specified files
will be matched from the directory.
-D format-options
Specify the archive format and format options, separated by com-
ma. tar currently supports the following formats and options:
ar The Unix Archiver library format. This format matches
APT repositories and the BSD ar(1) specification, not
GNU binutils (which can however read them) or SYSV sys-
tems. See ar(5) on some operating systems for more in-
formation.
bcpio The old binary cpio format. The default blocksize for
this format is 5120 bytes. This format is not very port-
able and should not be used when other formats are
available. Inode and device information about a file
(used for detecting file hard links by this format),
which may be truncated by this format, is detected by
tar and is repaired.
cpio The extended cpio interchange format specified in the
IEEE Std 1003.2 ("POSIX.2") standard. The default block-
size for this format is 5120 bytes. Inode and device in-
formation about a file (used for detecting file hard
links by this format), which may be truncated by this
format, is detected by tar and is repaired.
sv4cpio The System V release 4 cpio. The default blocksize for
this format is 5120 bytes. Inode and device information
about a file (used for detecting file hard links by this
format), which may be truncated by this format, is
detected by tar and is repaired.
sv4crc The System V release 4 cpio with file CRC checksums. The
default blocksize for this format is 5120 bytes. Inode
and device information about a file (used for detecting
file hard links by this format), which may be truncated
by this format, is detected by tar and is repaired.
tar The old BSD tar format as found in 4.3BSD. The default
blocksize for this format is 10240 bytes. Pathnames
stored by this format must be 100 characters or less in
length. Only regular files, hard links, symlinks and
directories will be archived (other filesystem types are
not supported).
For backwards compatibility with even older tar formats,
the write_opt=nodir option can be used when writing an
archive to omit the storage of directories.
ustar The extended tar interchange format specified in the
IEEE Std 1003.2 ("POSIX.2") standard. The default block-
size for this format is 10240 bytes. Filenames stored by
this format must be 100 characters or less in length;
the total pathname must be 256 characters or less.
tar will detect and report any file that it is unable to store or
extract as the result of any specific archive format restric-
tions. The individual archive formats may impose additional res-
trictions on use. Typical archive format restrictions include
(but are not limited to): file pathname length, file size, link
pathname length, and the type of the file.
-e Stop after the first error.
-f archive
Filename where the archive is stored. Defaults to /dev/rst0. If
set to hyphen ('-') standard output is used. See also the TAPE
environment variable.
-H Follow symlinks given on the command line only.
-h Follow symbolic links as if they were normal files or direc-
tories. In extract mode this means that a directory entry in the
archive will not overwrite an existing symbolic link, but rather
what the link ultimately points to.
-I file
This is a positional argument which reads the names of files to
archive or extract from the given file, one per line.
-J Use the xz utility to compress the archive.
-j Use the bzip2 utility to compress the archive.
-L Synonym for the -h option.
-M flag
Configure the archive normaliser. flag is either a numeric value
compatible to strtonum(3) which is directly stored in the flags
word, or one of the following values, optionally prefixed with
"no-" to turn them off:
inodes 0x0001: Serialise inodes, zero device info.
(cpio, sv4cpio, sv4crc)
links 0x0002: Store content of hard links only once.
(cpio, sv4cpio, sv4crc)
mtime 0x0004: Zero out the file modification time.
(ar, cpio, sv4cpio, sv4crc, ustar)
uidgid 0x0008: Set owner to 0:0 (root:wheel).
(ar, cpio, sv4cpio, sv4crc, ustar)
verb 0x0010: Debug this option.
debug 0x0020: Debug file header storage.
lncp 0x0040: Extract hard links by copy if link fails.
numid 0x0080: Use only numeric uid and gid values.
(ustar)
gslash 0x0100: Append a slash after directory names.
(ustar)
set 0x0003: Keep ownership and mtime intact.
dist 0x008B: Clean everything except mtime.
norm 0x008F: Clean everything.
root 0x0089: Clean owner and device information.
When creating an archive and verbosely listing output, these nor-
malisation operations are not reflected in the output, because
they are made only after the output has been shown.
This option is only implemented for the ar, cpio, sv4cpio,
sv4crc, and ustar file format writing routines.
-m Do not preserve modification time.
-O If reading, extract files to standard output.
If writing, write old-style (non-POSIX) archives.
-o If writing, write old-style (non-POSIX) archives.
Don't write directory information that the older (V7) style tar
is unable to decode. Same as -D tar,write_opt=nodir.
-P For security reasons, tar skips pathnames containing dotdot
("..") components and strips leading slashes ('/') from pathnames
by default; this option disables that behaviour.
-p Preserve user and group ID as well as file mode regardless of the
current umask(2). The setuid and setgid bits are only preserved
if the user and group ID could be preserved. Only meaningful in
conjunction with the -x flag.
-q Select the first archive member that matches each file operand.
No more than one archive member is matched for each file. When
members of type directory are matched, the file hierarchy rooted
at that directory is also matched.
-s replstr
Modify the archive member names according to the substitution ex-
pression replstr, using the syntax of the ed(1) utility regular
expressions. file arguments may be given to restrict the list of
archive members to those specified.
The format of these regular expressions is
/old/new/[gp]
As in ed(1), old is a basic regular expression (see re_format(7))
and new can contain an ampersand ('&'), '\n' (where n is a digit)
back-references, or subexpression matching. The old string may
also contain newline characters. Any non-null character can be
used as a delimiter ('/' is shown here). Multiple -s expressions
can be specified. The expressions are applied in the order they
are specified on the command line, terminating with the first
successful substitution.
The optional trailing g continues to apply the substitution ex-
pression to the pathname substring, which starts with the first
character following the end of the last successful substitution.
The first unsuccessful substitution stops the operation of the g
option. The optional trailing p will cause the final result of a
successful substitution to be written to standard error in the
following format:
original-pathname >> new-pathname
File or archive member names that substitute to the empty string
are not selected and will be skipped.
-v Verbose operation mode. If -v is specified multiple times or if
the -t option is also specified, tar will use a long format for
listing files, similar to ls(1) -l.
-w Interactively rename files. This option causes tar to prompt the
user for the filename to use when storing or extracting files in
an archive.
-X Do not cross mount points in the filesystem.
-Z Use the compress(1) utility to compress the archive.
-z Use the gzip(1) utility to compress the archive.
The options [-014578] can be used to select one of the compiled-in backup
devices, /dev/rstN.
ENVIRONMENT
TMPDIR Path in which to store temporary files.
TAPE Default tape device to use instead of /dev/rst0. If set to
hyphen ('-') standard output is used.
FILES
/dev/rst0 default archive name
EXIT STATUS
The tar utility exits with one of the following values:
0 All files were processed successfully.
1 An error occurred.
EXAMPLES
Create an archive on the default tape drive, containing the files named
bonvole and sekve:
$ tar c bonvole sekve
Output a gzip(1) compressed archive containing the files bonvole and
sekve to a file called foriru.tar.gz:
$ tar zcf foriru.tar.gz bonvole sekve
Verbosely create an archive, called backup.tar.gz, of all files matching
the shell glob(7) function *.c:
$ tar zcvf backup.tar.gz *.c
Verbosely list, but do not extract, all files ending in .jpeg from a
compressed archive named backup.tar.gz. Note that the glob pattern has
been quoted to avoid expansion by the shell:
$ tar tvzf backup.tar.gz '*.jpeg'
For more detailed examples, see pax(1).
DIAGNOSTICS
Whenever tar cannot create a file or a link when extracting an archive or
cannot find a file while writing an archive, or cannot preserve the user
ID, group ID, file mode, or access and modification times when the -p op-
tion is specified, a diagnostic message is written to standard error and
a non-zero exit value will be returned, but processing will continue. In
the case where tar cannot create a link to a file, unless -M lncp is
given, tar will not create a second copy of the file.
If the extraction of a file from an archive is prematurely terminated by
a signal or error, tar may have only partially extracted the file the
user wanted. Additionally, the file modes of extracted files and direc-
tories may have incorrect file bits, and the modification and access
times may be wrong.
If the creation of an archive is prematurely terminated by a signal or
error, tar may have only partially created the archive, which may violate
the specific archive format specification.
SEE ALSO
ar(1), cpio(1), pax(1)
HISTORY
A tar command first appeared in Version 7 AT&T UNIX.
AUTHORS
Keith Muller at the University of California, San Diego. MirBSD exten-
sions by mirabilos <m@mirbsd.org>.
CAVEATS
The flags -aDJjLMo are not portable to other implementations of tar where
they may have a different meaning or not exist at all.
This implementation may have support for other non-standard options that
are undocumented because removal-inducing deprecation was issued.
BUGS
The pax file format is not yet supported.
MirBSD September 23, 2021 5