tar(1) tar(1)
NAME
tar - file archiver
SYNOPSIS
/usr/sbin/tar -c[vwfbLkFhienA[num]] [device] [block] [volsize] [incfile] [files]...
/usr/sbin/tar -c[vwfbLkXhienA[num]] [device] [block] [volsize] [excfile] [files]...
/usr/sbin/tar -r[vwfbLkFhienA[num]] [device] [block] [volsize] [incfile] [files]...
/usr/sbin/tar -r[vwfbLkXhienA[num]] [device] [block] [volsize] [excfile] [files]...
/usr/sbin/tar -t[vfLXien[num] device excfile [files . . .]
/usr/sbin/tar -u[vwfbLkXhienA[num]] [device] [block] [volsize] [excfile] [files]...
/usr/sbin/tar -u[vwfbLkFhienA[num]] [device] [block] [volsize] [incfile] [files]...
/usr/sbin/tar -x[lmovwfLXpienA[num]] device excfile [files . . . ]
DESCRIPTION
tar saves files on an archive medium (such as a floppy
diskette or a tape) and restores them from that medium. Its
actions are controlled by a string of characters containing
one option (c, r, t, u, or x), and possibly followed by one or
more modifiers (v, w, f, b, L, k, F, X, h, i, e, n, A, l, m,
o, p, and num). Other arguments to the command are files (or
directory names) specifying which files are to be dumped or
restored. In all cases, appearance of a directory name refers
to the files and (recursively) subdirectories of that
directory.
tar uses the following criteria, listed in descending order of
precedence, to determine which device to use:
Is -f device specified on the command line?
Is the TAPE environment variable set?
Is the num modifier used on the command line? (tar looks
up the specified device in /etc/default/tar.)
If none of the above are true, tar uses the default
device specified by the entry ``archive='' in
/etc/default/tar.
The options are as follows:
-c Create a new archive; writing begins at the beginning
of the archive, instead of after the last file.
Copyright 1994 Novell, Inc. Page 1
tar(1) tar(1)
-r The named files are written on the end of an existing
archive. This option cannot be used if the archive is
a tape. You may need to use the n modifier with this
option.
-t The names and other information for the specified
files are listed each time they occur on the archive.
This is true only if the v modifier is used. With no
v, you get only pathnames. The listing is similar to
the format produced by the ls -l command. [See
ls(1)]. If no files argument is given, all the names
in the archive are listed.
-u The named files are added to the archive if they are
not already there, or have been modified since last
written on that archive. This option cannot be used
if the archive is a tape. You may need to use the n
modifier with this option.
-x The named files are extracted from the archive. If a
named file matches a directory whose contents have
been written onto the archive, this directory is
(recursively) extracted. Use the file or directory's
relative path when appropriate, or tar will not find a
match. The owner, modification time, and mode are
restored (if possible). If no files argument is
given, the entire contents of the archive are
extracted.
The modifiers below may be used in the order shown in the
synopsis.
num This modifier allows you to specify, via the file
/etc/default/tar, the device to be used for creating
or extracting an archive. Specify a number up to 9999
as the value of num. tar looks for the
``archivenum='' entry in /etc/default/tar and uses the
device name specified there. By default (that is, if
you specify neither -f nor num on the command line),
tar looks for the ``archive='' entry.
In addition to the device name, an entry in
/etc/default/tar specifies the blocking factor and the
volume size to be used for that device (see the b and
t modifiers). An optional fourth field indicates
whether or not the device is a tape (see n modifier).
Copyright 1994 Novell, Inc. Page 2
tar(1) tar(1)
A word starting with ``n'' or ``N'' indicates it is
not a tape. Anything else means it is a tape. If the
fourth field is not present, tar considers the device
a tape if the volume size field (third field) is 0,
and not a tape if it is non-zero. For example, the
default device entry in /etc/default/tar might look
like:
archive=/dev/rdsk/f05ht 15 1200 N
where 15 is the blocking factor, 1200 is the volume
size (in kilobytes), and the device is not a tape.
v Normally, tar does its work silently. The v (verbose)
modifier causes it to print the name of each file it
treats, preceded by the option. With the -t option, v
gives more information about the archive entries than
just the name.
w This modifier causes tar to print the action to be
taken, followed by the name of the file, and then wait
for your confirmation. If a word beginning with y is
given, the action is performed. Any other input means
no. This is not valid with the -t option.
f This causes tar to use the device argument as the name
of the archive instead of the default. If the name of
the file is -, tar writes to the standard output or
reads from the standard input, whichever is
appropriate. Thus, tar can be used as the head or
tail of a pipeline. tar can also be used to move
hierarchies with the command:
cd fromdir; tar cf - . | (cd todir; tar xf -)
b This modifier causes tar to use the block argument as
the blocking factor for archive records. The default
is 1. The maximum is 20. This modifier should not be
supplied when operating on regular archives or block
special devices. It is mandatory however, when
reading archives on raw magnetic tape archives (see f
above). The blocking factor is determined
automatically when reading tapes created on block
special devices (options x and t). The block size is
512 bytes.
Copyright 1994 Novell, Inc. Page 3
tar(1) tar(1)
l This modifier causes tar to complain if it cannot
resolve all of the links to the files being dumped.
If the l modifier is not specified, no error messages
are printed.
m This modifier causes tar to not restore the
modification times. The modification time of the file
will be the time of extraction.
o This modifier causes extracted files to take on the
user and group identifier of the user running the
program, rather than those on tape. This is valid
only with the -x option.
L Follow symbolic links. This modifier causes symbolic
links to be followed. By default, symbolic links are
not followed. This modifier means the same thing as
the h modifier (below). Both are provided for
backwards compatibility.
k This modifier, which must be used with multi-volume
archives, uses the volsize argument as the size, in
kilobytes per volume, for tape and non-tape devices
(such as floppy drives). The argument to -k should be
a multiple of the blocking factor; if it isn't, tar
will round it down to the nearest such multiple. A
value of 0 for volsize causes multi-volume mode to be
disabled (interpreted as an infinite volume size).
This modifier may be used with the -c, -r, and -u
options.
When restoring from a multi-volume archive, tar
prompts for a new volume only if a split file has been
partially restored. Otherwise tar exits at the end of
the volume. If this happens, run the tar command
again for the next volume.
F This modifier uses the incfile argument as a file
containing a list of named files (or directories) to
be included in the archive. This modifier may only be
used with the -c, -r, and -u options. This modifier
may not be used with the X modifier.
X This modifier uses the excfile argument as a file
containing a list of named files (or directories) to
be excluded. This modifier may not be used with the F
Copyright 1994 Novell, Inc. Page 4
tar(1) tar(1)
modifier.
h This modifier causes tar to follow symbolic links as
if they were normal files or directories. Normally
tar does not follow symbolic links. The h modifier
may be used with the -c, -r, and -u options.
p This modifier restores the named file arguments to
their original modes, ignoring the present value
returned by umask. [See umask(2)]. setuid and sticky
bit information are also restored if the effective
user ID is root. This modifier may only be used with
the -x option.
i This modifier causes tar to ignore directory checksum
errors.
e This modifier causes tar to quit when certain minor
errors are encountered. Otherwise tar will continue
when minor errors are encountered.
n This modifier is used to tell tar that the device is
not a tape. If tar has an incorrect idea of whether
of not the device is a tape, undesirable results may
occur. If tar gets the device entry from
/etc/default/tar, it will use this entry to determine
whether the device is a tape, as described under the
num modifier. Otherwise, tar assumes the device is a
tape, unless this modifier is used.
A This modifier causes absolute pathnames for files to
be suppressed, and may be used with the -r, -c, -u,
and -x options. This causes all pathnames to be
interpreted as relative to the current working
directory.
USAGE
If you set the TAPE environment variable to /dev/rmt/ctape1n
and run the command tar -cf /dev/rmt/ctape1, the default
device used will be /dev/rmt/ctape1.
If you set the TAPE environment variable to /dev/rmt/ctape1n
and run the command tar -c0h, the device used will be
/dev/rmt/ctape1n rather than the 0 entry of /etc/default/tar.
Copyright 1994 Novell, Inc. Page 5
tar(1) tar(1)
Reading from magnetic tape in any fixed-length block length
besides the block length that the media was written in
originally will cause an I/O error. If you want to read a
tape that was written using a block-length besides the default
of 512, you must use the tapecntl(1) command ( qv ) to either
set the block-length of the drive to match the block length of
the media or to set the drive into variable block length mode.
Errors
Complains about tape read/write errors.
Complains if insufficient memory is available to hold the link
tables.
Files
/etc/default/tar
/tmp/tar*
/usr/lib/locale/locale/LC_MESSAGES/uxcore
language-specific message file
[See LANG on environ(5)].
REFERENCES
ar(1), cpio(1), ls(1), umask(2)
NOTICES
There is no way to ask for the n-th occurrence of a file.
The current limit on file name length is 100 characters.
Because cpio can recognize archives that have been formatted
with tar, it can be used as an alternative command for reading
tar archives.
On a pre-Release 4 system, you cannot restore archives of
directories, subdirectories, or files within directories that
have been created with UNIX System V Release 4 tar. (That is,
only files at the level of the current directory can be
restored.) If you try to do so, you will get error messages
saying files cannot be created.
Using variable-length block mode when writing magnetic tapes
is discouraged because it may not work correctly in releases
before SVR4.2 MP. Magnetic tape should always be written in
fixed-length block mode, even though you are free to change
Copyright 1994 Novell, Inc. Page 6
tar(1) tar(1)
the default fixed-block length from 512 bytes to any other
fixed-block mode the tape drive supports.
Reading from magnetic tape in any fixed-length block length,
besides the block length that the media was written in
originally, will cause an I/O error. In order to read a tape
that was written using some block length besides the default
of 512, use the tapecntl(1) command (qv) to either set the
block length of the drive to match the block length of the
media, or to set the drive into variable block length mode.
Copyright 1994 Novell, Inc. Page 7