path: root/bin/pax/tar.1

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.\" Copyright (c) 1996 SigmaSoft, Th. Lockert
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.\"      This product includes software developed by SigmaSoft, Th. Lockert.
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.\"	$OpenBSD: tar.1,v 1.5 1997/03/26 01:14:14 millert 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
.\" XXX how to do this right?
.No [-C
.Ar directory
.No ]
.No [-s
.Ar replstr
.No ]
.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 "blocking factor"
Set blocking factor to use for archive,
.Nm tar
uses 512 byte blocks.  The blocking factor may not be larger
than 63 (32256 bytes).
.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 s Ar replstr
Modify the file or archive member names specified by the
.Ar pattern
or
.Ar file
operands according to the substitution expression
.Ar replstr ,
using the syntax of the
.Xr ed 1
utility regular expressions.
The format of these regular expressions are:
.Dl /old/new/[gp]
As in
.Xr ed 1 ,
.Cm old
is a basic regular expression and
.Cm new
can contain an ampersand (&), \\n (where n is a digit) back-references,
or subexpression matching.
The
.Cm old
string may also contain
.Dv <newline>
characters.
Any non-null character can be used as a delimiter (/ is shown here).
Multiple
.Fl 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
.Cm 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
.Cm g
option.
The optional trailing
.Cm p
will cause the final result of a successful substitution to be written to
.Dv standard error
in the following format:
.Dl <original pathname> >> <new pathname>
File or archive member names that substitute to the empty string
are not selected and will be skipped.
.It Fl v
Verbose operation mode.
.It Fl w
Interactively rename files.
.It Fl z
Compress archive using gzip.
.It Fl C Ar 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.
.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.