.\" Copyright (c) 1990 The Regents of the University of California.
.\" This module is believed to contain source code proprietary to AT&T.
.\" Use and redistribution is subject to the Berkeley Software License
.\" Agreement and your Software Agreement with AT&T (Western Electric).
.\" @(#)tar.1 6.14 (Berkeley) 7/27/92
saves and restores multiple files on a single file (usually a magnetic
tape, but it can be any file).
actions are controlled by the
is a string of characters containing at most one function letter and possibly
one or more function modifiers. Other arguments to
are file or directory names specifying which files to dump or restore.
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:
The named files are written on the end of the tape. The
The named files are extracted from the tape. If the named file
matches a directory whose contents had been written onto the tape, this
directory is (recursively) extracted. The owner, modification time, and mode
are restored (if possible). If no file argument is given, the entire content
of the tape is extracted. Note that if multiple entries specifying the same
file are on the tape, the last one overwrites all earlier.
The names of the specified files are listed each time they occur on
the tape. If no file argument is given, all of the names on the tape
The named files are added to the tape if either they are not
already there or have been modified since last put on the tape.
Create a new tape; writing begins on the beginning of the tape
instead of after the last file. This command implies
The following characters may be used in addition to the letter
which selects the function desired.
On output, tar normally places information specifying owner and modes
of directories in the archive. Former versions of tar, when encountering
this information will give error message of the form
.Dl <name>/: cannot create.
This modifier will suppress the directory information.
This modifier says to restore files to their original modes,
Setuid and sticky information
will also be restored to the super-user.
This modifier selects an alternate drive on which the tape is mounted.
The default is drive 0 at 1600 bpi, which is normally
does its work silently. The
print the name of each file it treats preceded by the function
function, the verbose option
gives more information about the tape entries than just their names.
prints the action to be taken followed by file name, then
wait for user confirmation. If a word beginning with
is given, the action is done. Any other input means don't do it.
uses the next argument as the name of the archive instead of
/dev/rmt?. If the name of the file is
tar writes to standard output or
reads from standard input, whichever is appropriate. Thus,
can be used as the head or tail of a filter chain.
can also be used to move hierarchies with the command
.Bd -literal -offset indent -compact
cd fromdir; tar cf - . | (cd todir; tar xf -)
uses the next argument as the blocking factor for tape records. The
default is 20 (the maximum). This option should only be used with raw magnetic
above). The block size is determined automatically
when reading tapes (key letters
to strip off any leading slashes from pathnames.
to complain if it cannot resolve all of the links to the
files dumped. If this is not specified, no error messages are printed.
not to restore the modification times. The modification time
will be the time of extraction.
to follow symbolic links as if they were normal files or
does not follow symbolic links.
to follow symbolic links on the command line only as if they were normal
files or directories. Normally,
does not follow symbolic links. Note that
Forces input and output blocking to 20 blocks per record. This option
can work across a communications channel where the blocking may not
If a file name is preceded by
to that file name. This allows multiple directories not
related by a close common parent to be archived using short
relative path names. For example, to archive files from /usr/include
and from /etc, one might use
.Bd -literal -offset indent -compact
tar c -C /usr include -C / etc
Previous restrictions dealing with
inability to properly handle blocked archives have been lifted.
.Bl -tag -width /dev/rmtxxx -compact
Complaints about bad key characters and tape read/write errors.
Complaints if enough memory is not available to hold the link tables.
There is no way to ask for the
Tape errors are handled ungracefully.
The current limit on file name length is 100 characters.
There is no way selectively to follow symbolic links.
When extracting tapes created with the
options, directory modification times may not be set correctly.