README for GNU tar Copyright 1990, 1991, 1992, 1994, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc. This file is part of GNU tar. GNU tar is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU tar is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with tar; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. Please glance through *all* sections of this `README' file before starting configuration. Also make sure you read files `ABOUT-NLS' and `INSTALL' if you are not familiar with them already. If you got the `tar' distribution in `shar' format, time stamps ought to be properly restored; do not ignore such complaints at `unshar' time. GNU `tar' saves many files together into a single tape or disk archive, and can restore individual files from the archive. It includes multivolume support, the ability to archive sparse files, automatic archive compression/decompression, remote archives and special features that allow `tar' to be used for incremental and full backups. This distribution also includes `rmt', the remote tape server. The `mt' tape drive control program is in the GNU `cpio' distribution. GNU `tar' is derived from John Gilmore's public domain `tar'. See file `ABOUT-NLS' for how to customize this program to your language. See file `COPYING' for copying conditions. See file `INSTALL' for compilation and installation instructions. See file `PORTS' for various ports of GNU tar to non-Unix systems. See file `NEWS' for a list of major changes in the current release. See file `THANKS' for a list of contributors. Besides those configure options documented in files `INSTALL' and `ABOUT-NLS', an extra option may be accepted after `./configure': * `--disable-largefile' omits support for large files, even if the operating system supports large files. Typically, large files are those larger on 2 GB on a 32-bit host. The default archive device is now `stdin' on read and `stdout' on write. The installer can still override this by presetting `DEFAULT_ARCHIVE' in the environment before configuring (the behavior of `-[0-7]' or `-[0-7]lmh' options in `tar' are then derived automatically). Similarly, `DEFAULT_BLOCKING' can be preset to something else than 20. For comprehensive modifications to GNU tar, you might need tools beyond those used in simple installations. Fully install GNU m4 1.4 first, and only then, Autoconf 2.13 or later. Install Perl, then Automake 1.4 or later. You might need Bison 1.28 or later, and GNU tar itself. All are available on GNU archive sites, like in ftp://ftp.gnu.org/pub/gnu/. Send bug reports to `bug-tar@gnu.org'. (Beware, old-timers: it is `@gnu', not `@prep'; and not `bug-gnu-utils' anymore.) A bug report is an adequate description of the problem: your input, what you expected, what you got, and why this is wrong. Diffs are welcome, but they only describe a solution, from which the problem might be uneasy to infer. If needed, submit actual data files with your report. Small data files are preferred. Big files may sometimes be necessary, but do not send them to the report address; rather take special arrangement with the maintainer. Your feedback will help us to make a better and more portable package. Consider documentation errors as bugs, and report them as such. If you develop anything pertaining to `tar' or have suggestions, let us know and share your findings by writing to . Installation hints ------------------ Here are a few hints which might help installing `tar' on some systems. * gzip and bzip2. GNU tar uses the gzip and bzip2 programs to read and write compressed archives. If you don't have these programs already, you need to install them. Their sources can be found at: ftp://ftp.gnu.org/gnu/gzip/ http://sourceware.cygnus.com/bzip2/ If you see the following symptoms: $ tar -xzf file.tar.gz gzip: stdin: decompression OK, trailing garbage ignored tar: Child returned status 2 then you have encountered a gzip incompatibility that should be fixed in gzip test version 1.3, which as of this writing is available at . You can work around the incompatibility by using a shell command like `gzip -d is not found (Slackware). * OPENStep 4.2 swap files Tar cannot read the file /private/vm/swapfile.front (even as root). This file is not a real file, but some kind of uncompressed view of the real compressed swap file; there is no reason to back it up, so the simplest workaround is to avoid tarring this file. Special topics -------------- Here are a few special matters about GNU `tar', not related to build matters. See previous section for such. * File attributes. About *security*, it is probable that future releases of `tar' will have some behavior changed. There are many pending suggestions to choose from. Today, extracting an archive not being `root', `tar' will restore suid/sgid bits on files but owned by the extracting user. `root' automatically gets a lot of special privileges, `-p' might later become required to get them. GNU `tar' does not properly restore symlink attributes. Various systems implement flavors of symbolic links showing different behavior and properties. We did not successfully sorted all these out yet. Currently, the `lchown' call will be used if available, but that's all. * POSIX compliance. GNU `tar' implements an early draft of the POSIX 1003.1 `ustar' standard which is different from the final standard. This will be progressively corrected over the incoming few years. Don't be mislead by the mere existence of the --posix option. Later releases will become able to read truly POSIX archives, and also to produce them under option. (Also, if you look at the internals, don't take the GNU extensions you see for granted, as they are planned to change.) GNU tar 2.0 will produce POSIX archives by default, but there is a long way before we get there. * What's next? In the future we will try to release tar-1.14 as soon as possible and start merging with paxutils afterwards. We'll also try to rewrite some parts of the documentation after paxutils has been merged.