.\"
.\" Copyright (c) 1996 SigmaSoft, Th. Lockert
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"      This product includes software developed by SigmaSoft, Th. Lockert.
.\" 4. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\"	$OpenBSD: tar.1,v 1.2 1996/08/10 03:08:00 tholo Exp $
.\"
.Dd June 11, 1996
.Dt TAR 1
.Os
.Sh NAME
.Nm tar
.Nd tape archiver
.Sh SYNOPSIS
.Nm tar
.No [-]{crtux}[befhmopvwzHLPXZ014578]
.Op Ar archive
.Op Ar blocksize
.Ar file1
.Op Ar file2...
.Sh DESCRIPTION
The
.Nm tar
command creates, adds files to, or extracts files from an
archive file in \*Qtar\*U format.  A tar archive is often
stored on a magnetic tape, but can be a floppy or a regular
disk file.
.Pp
One of the following flags must be present:
.Bl -tag -width Ar
.It Fl c
Create new archive, or overwrite an existing archive,
adding the specified files to it.
.It Fl 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.
.It Fl t
List contents of archive.  If any files are named on the
command line, only those files will be listed.
.It Fl u
Alias for
.Fl r
.It Fl x
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
extration.
.El
.Pp
In addition to the flags mentioned above, any of the following
flags may be used:
.Bl -tag -width Ar
.It Fl b Ar blocksize
Set block size to use for archive.  Any multiple of 512 between
10240 and 32256 may be used.
.It Fl e
Stop after first error.
.It Fl f Ar archive
Filename where the archive is stored.  Defaults to
.Pa /dev/rmt8
.It Fl h
Follow symbolic links as if they were normal files
or directories.
.It Fl m
Do not preserve modification time.
.It Fl o
Do not create directories.
.It Fl p
Preserve user id, group id, file mode, access and modification
times.
.It Fl v
Verbose operation mode.
.It Fl w
Interactively rename files.
.It Fl z
Compress archive using gzip.
.It Fl H
Follow symlinks given on command line only.
.It Fl L
Follow all symlinks.
.It Fl P
Do not follow any symlinks.
.It Fl X
Do not cross mount points in the file system.
.It Fl Z
Compress archive using compress.
.El
.Pp
The options
.Op Fl 014578
can be use to select one of the compiled-in backup devices,
.Pa /dev/rmtN .
.Sh FILES
.Bl -tag -width "/dev/rmt8"
.It Pa /dev/rmt8
The default archive name
.El
.Sh SEE ALSO
.Xr pax 1 ,
.Xr cpio 1
.Sh AUTHOR
Keith Muller at the University of California, San Diego
.Sh ERRORS
.Nm tar
will exit with one of the following values:
.Bl -tag -width 2n
.It 0
All files were processed successfully.
.It 1
An error occured.
.El
.Pp
Whenever
.Nm 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
.Fl p
options 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
.Nm tar
cannot create a link to a file,
.Nm tar
will not create a second copy of the file.
.Pp
If the extraction of a file from an archive is prematurely terminated
by a signal or error,
.Nm 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.
.Pp
If the creation of an archive is prematurely terminated by a signal
or error,
.Nm tar
may have only partially created the archive which may violate the
specific archive format specification.