tar(1) (Essential Utilities) tar(1)
NAME
tar - tape file archiver
SYNOPSIS
/usr/sbin/tar -c[vwfbL[#s]] device block files ...
/usr/sbin/tar -r[vwfbL[#s]] device block files ...
/usr/sbin/tar -t[vfL[#s] device [files ...]
/usr/sbin/tar -u[vwfbL[#s]] device block files ...
/usr/sbin/tar -x[lmovwfL[#s]] device [files ...]
DESCRIPTION
tar saves and restores files on magnetic tape. Its actions are
controlled by the key argument. The key is a string of characters
containing one function letter (c, r, t, u, or x) and possibly
followed by one or more function modifiers (v, w, f, b, and #).
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.
The function portion of the key is specified by one of the following
letters:
c Create a new tape; writing begins at the beginning of the
tape, instead of after the last file. This key implies the r
key.
r Replace. The named files are written on the end of the tape.
The c and u functions imply this function.
t Table. The names and other information for the specified
files are listed each time that they occur on the tape. The
listing is similar to the format produced by the ls -l
command. If no files argument is given, all the names on the
tape are listed.
u Update. The named files are added to the tape if they are
not already there, or have been modified since last written
on that tape. This key implies the r key.
x Extract. The named files are extracted from the tape. If a
named file matches a directory whose contents had been
written onto the tape, 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 content of the tape is
extracted. Note that if several files with the same name are
on the tape, the last one overwrites all earlier ones.
The characters below may be used in addition to the letter that
selects the desired function. Use them in the order shown in the
synopsis.
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tar(1) (Essential Utilities) tar(1)
#s This modifier determines the drive on which the tape is
mounted (replace # with the drive number) and the speed of
the drive (replace s with l, m, or h for low, medium or
high). The modifier tells tar to use a drive other than the
default drive, or the drive specified with the -f option.
For example, with the 5h modifier, tar would use /dev/mt/5h
or /dev/mt0 instead of the default drives /dev/mt/0m or
/dev/mt0, respectively. However, if for example, -f /dev/rmt0
5h appeared on the command line, tar would use /dev/rmt5h or
/devmt0. The default entry is 0m.
v Verbose. Normally, tar does its work silently. The v
(verbose) option causes it to type the name of each file it
treats, preceded by the function letter. With the t
function, v gives more information about the tape entries
than just the name.
w What. This causes tar to print the action to be taken,
followed by the name of the file, and then wait for the
user's 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 key.
f File. This causes tar to use the device argument as the name
of the archive instead of /dev/mt/0m or /dev/mt0. 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 Blocking Factor. This causes tar to use the block argument
as the blocking factor for tape records. The default is 1,
the maximum is 20. This function 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 block size is determined
automatically when reading tapes created on block special
devices (key letters x and t).
l Link. This tells tar to complain if it cannot resolve all of
the links to the files being dumped. If l is not specified,
no error messages are printed.
m Modify. This tells tar to not restore the modification
times. The modification time of the file will be the time of
extraction.
o Ownership. This causes extracted files to take on the user
and group identifier of the user running the program, rather
than those on tape. This is only valid with the x key.
L Follow symbolic links. This causes symbolic links to be
followed. By default, symbolic links are not followed.
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tar(1) (Essential Utilities) tar(1)
FILES
/dev/mt/*
/dev/mt*
/dev/mt/ctape
/dev/mt/0m
/dev/rmt/0m
/tmp/tar*
SEE ALSO
ar(1), cpio(1), ls(1).
DIAGNOSTICS
Complaints about bad key characters and tape read/write errors.
Complaints if enough memory is not available to hold the link tables.
NOTES
There is no way to ask for the n-th occurrence of a file.
Tape errors are handled ungracefully.
The u option can be slow.
The b option should not be used with archives that are going to be
updated. The current magnetic tape driver cannot backspace raw
magnetic tape. If the archive is on a disk file, the b option should
not be used at all, because updating an archive stored on disk can
destroy it.
The current limit on file name length is 100 characters.
tar doesn't copy empty directories or special files.
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