NAME
tar —
tape archiver
SYNOPSIS
tar |
[-]{crtux}[-014578befHhJjklmOoPpqSvwXZz]
[archive]
[blocksize]
[-C
directory]
[-s
replstr]
[-T file]
[file ...] |
DESCRIPTION
The
tar command creates, adds files to, or extracts files from
an archive file in “tar” 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.
One of the following flags must be present:
-
-
- -c,
--create
- Create new archive, or overwrite an existing archive,
adding the specified files to it.
-
-
- -r,
--append
- 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
- List contents of archive. If any files are named on the
command line, only those files will be listed.
-
-
- -u,
--update
- Alias for -r.
-
-
- -x,
--extract,
--get
- Extract files from archive. If any files are named on the
command line, only those files will be extracted from the archive. 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:
-
-
- -b
blocking factor,
--block-size 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 63 violate the POSIX
standard and will not be portable to all systems.
-
-
- -e
- Stop after first error.
-
-
- -f
archive, --file
archive
- Filename where the archive is stored. Defaults to
/dev/rst0. If the archive is of the form:
[[user@]host:]file then the archive will be
processed using rmt(8).
-
-
- -h,
--dereference
- Follow symbolic links as if they were normal files or
directories.
-
-
- -J,
--xz
- Compress/decompress archive using
xz(1).
-
-
- -j,
--bzip2,
--bunzip2
- Use bzip2(1)
for compression of the archive. This option is a GNU extension.
-
-
- -k,
--keep-old-files
- Keep existing files; don't overwrite them from
archive.
-
-
- -l,
--one-file-system
- Do not descend across mount points.
-
-
- -m,
--modification-time
- Do not preserve modification time.
-
-
- -O
- When creating and appending to an archive, write old-style
(non-POSIX) archives. When extracting from an archive, extract to standard
output.
-
-
- -o,
--portability,
--old-archive
- Don't write directory information that the older (V7) style
tar is unable to decode. This implies the
-O flag.
-
-
- -p,
--preserve-permissions,
- -preserve
- 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 is the superuser.
Only meaningful in conjunction with the -x flag.
-
-
- -q,
--fast-read
- Select the first archive member that matches each
pattern operand. No more than one archive member is
matched for each pattern. When members of type
directory are matched, the file hierarchy rooted at that directory is also
matched.
-
-
- -S,
--sparse
- This flag has no effect as tar always
generates sparse files.
-
-
- -s
replstr
- Modify the file or archive member names specified by the
pattern or file operands
according to the substitution expression replstr,
using the syntax of the ed(1)
utility regular expressions. The format of these regular expressions are:
/old/new/[gps]
As in ed(1), old
is a basic regular expression 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 expression 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. The substitutions are applied by default to
the destination hard and symbolic links. The optional trailing
s prevents the substitutions from being performed on
symbolic link destinations.
-
-
- -v
- Verbose operation mode.
-
-
- -w,
--interactive,
--confirmation
- Interactively rename files. This option causes
tar to prompt the user for the filename to use when
storing or extracting files in an archive.
-
-
- -z,
--gzip,
--gunzip
- Compress/decompress archive using
gzip(1).
-
-
- -B,
--read-full-blocks
- Reassemble small reads into full blocks (For reading from
4.2BSD pipes).
-
-
- -C
directory,
--directory
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. This argument and its parameter may
also appear in a file list specified by -T.
-
-
- -H
- Only follow symlinks given on command line.
Note SysVr3/i386 picked up ISC/SCO UNIX compatibility which implemented
“-F file” which was
defined as obtaining a list of command line switches and files on which to
operate from the specified file, but SunOS-5 uses
“-I file” because they
use ‘-F’ to mean something else. We might
someday provide SunOS-5 compatibility but it makes little sense to confuse
things with ISC/SCO compatibility.
-
-
- -P,
--absolute-paths
- Do not strip leading slashes (‘/’) from
pathnames. The default is to strip leading slashes.
-
-
- -T
file, --files-from
file
- Read the names of files to archive or extract from the
given file, one per line. A line may also specify the positional argument
“-C directory”.
-
-
- -X
file,
--exclude-from
file
- Exclude files matching the shell glob patterns listed in
the given file.
Note that it would be more standard to use this option to mean ``do not
cross filesystem mount points.''
-
-
- -Z,
--compress,
--uncompress
- Compress archive using compress.
-
-
- --strict
- Do not enable GNU tar extensions such as long filenames and
long link names.
-
-
- --atime-preserve
- Preserve file access times.
-
-
- --chroot
- chroot() to the current directory before
extracting files. Use with -x and -h
to make absolute symlinks relative to the current directory.
-
-
- --unlink
- Ignored, only accepted for compatibility with other
tar implementations. tar always
unlinks files before creating them.
-
-
- --use-compress-program
program
- Use the named program as the program to decompress the
input.
-
-
- --force-local
- Do not interpret filenames that contain a ‘:’
as remote files.
-
-
- --insecure
- Normally tar ignores filenames that
contain “..” as a path component. With this option, files that
contain “..” can be processed.
-
-
- --no-recursion
- Cause files of type directory being copied or archived, or
archive members of type directory being extracted, to match only the
directory file or archive member and not the file hierarchy rooted at the
directory.
-
-
- --timestamp
timestamp
- Store all modification times in the archive with the
timestamp given instead of the actual modification
time of the individual archive member so that repeatable builds are
possible. The timestamp can be a
pathname, where the timestamps are derived from that
file, a parseable date for
parsedate(3) (this option
is not yet available in the tools build), or an integer value interpreted
as the number of seconds from the Epoch.
The options [
-014578] can be used to
select one of the compiled-in backup devices,
/dev/rstN.
FILES
-
-
- /dev/rst0
- default archive name
DIAGNOSTICS
tar will exit with one of the following values:
-
-
- 0
- All files were processed successfully.
-
-
- 1
- An error occurred.
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 option 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,
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
directories 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
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.