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@@ -0,0 +1,253 @@ +README for GNU tar +See the end of file for copying conditions. + +* Introduction + +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 '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': + +* Install + +** Selecting the default archive format. + +The default archive format is GNU, this can be overridden by +presetting DEFAULT_ARCHIVE_FORMAT while configuring. The allowed +values are GNU, V7, OLDGNU, USTAR and POSIX. + +** Selecting the default archive device + +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. + +** Selecting full pathname of the "rmt" binary. + +Previous versions of tar always looked for "rmt" binary in the +directory "/etc/rmt". However, the "rmt" program included +in the distribution was installed under "$prefix/libexec/rmt". +To fix this discrepancy, tar now looks for "$prefix/libexec/rmt". +If you do not want this behavior, specify full path name of +"rmt" binary using DEFAULT_RMT_DIR variable, e.g.: + +./configure DEFAULT_RMT_DIR=/etc + +If you already have a copy of "rmt" installed and wish to use it +instead of the version supplied with the distribution, use --with-rmt +option: + +./configure --with-rmt=/etc/rmt + +This will also disable building the included version of rmt. + +** Installing backup scripts. + +This version of tar is shipped with the shell scripts for producing +incremental backups (dumps) and restoring filesystems from them. +The name of the backup script is "backup". The name of the +restore script is "restore". They are installed in "$prefix/sbin" +directory. + +Use option --enable-backup-scripts to compile and install these +scripts. + +** '--disable-largefile' omits support for large files, even if the +operating system supports large files. Typically, large files are +those larger than 2 GB on a 32-bit host. + +* 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 +<ftp://alpha.gnu.org/gnu/gzip/>. You can work around the +incompatibility by using a shell command like + 'gzip -d <file.tar.gz | tar -xzf -'. + +** Solaris issues. + +GNU tar exercises many features that can cause problems with older GCC +versions. In particular, GCC 2.8.1 (sparc, -O1 or -O2) is known to +miscompile GNU tar. No compiler-related problems have been reported +when using GCC 2.95.2 or later. + +Recent versions of Solaris tar sport a new -E option to generate +extended headers in an undocumented format. GNU tar does not +understand these headers. + +** Static linking. + +Some platform will, by default, prepare a smaller 'tar' executable +which depends on shared libraries. Since GNU 'tar' may be used for +system-level backups and disaster recovery, installers might prefer to +force static linking, making a bigger 'tar' executable maybe, but able to +work standalone, in situations where shared libraries are not available. +The way to achieve static linking varies between systems. Set LDFLAGS +to a value from the table below, before configuration (see 'INSTALL'). + + Platform Compiler LDFLAGS + + (any) Gnu C -static + AIX (vendor) -bnso -bI:/lib/syscalls.exp + HPUX (vendor) -Wl,-a,archive + IRIX (vendor) -non_shared + OSF (vendor) -non_shared + SCO 3.2v5 (vendor) -dn + Solaris (vendor) -Bstatic + SunOS (vendor) -Bstatic + +** Failed tests 'ignfail.sh' or 'incremen.sh'. + +In an NFS environment, lack of synchronization between machine clocks +might create difficulties to any tool comparing dates and file time stamps, +like 'tar' in incremental dumps. This has been a recurrent problem with +GNU Make for the last few years. We would like a general solution. + +** BSD compatibility matters. + +Set LIBS to '-lbsd' before configuration (see 'INSTALL') if the linker +complains about 'bsd_ioctl' (Slackware). Also set CPPFLAGS to +'-I/usr/include/bsd' if <sgtty.h> 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' is able to create archive in the following formats: + + *** The format of UNIX version 7 + *** POSIX.1-1988 format, also known as "ustar format" + *** POSIX.1-2001 format, also known as "pax format" + *** Old GNU format (described below) + +In addition to those, GNU 'tar' is also able to read archives +produced by 'star' archiver. + +A so called 'Old GNU' format is based on an early draft of the +POSIX 1003.1 'ustar' standard which is different from the final +standard. It defines its extensions (such as incremental backups +and handling of the long file names) in a way incompatible with +any existing tar archive format, therefore the use of old GNU +format is strongly discouraged. + +Please read the file NEWS for more information about POSIX compliance +and new 'tar' features. + +* What's next? + +GNU tar will be merged into GNU paxutils: a project containing +several utilities related to creating and handling archives in +various formats. The project will include tar, cpio and pax +utilities. + +* Bug reporting. + +Send bug reports to <bug-tar@gnu.org>. A bug report should contain +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 <bug-tar@gnu.org>. + + +* Copying + +Copyright 1990-1992, 1994, 1997-2001, 2003-2004, 2007, 2012-2014, 2016 +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 3 of the License, 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 this program. If not, see <http://www.gnu.org/licenses/>. + +NOTE ON COPYRIGHT YEARS + +In copyright notices where the copyright holder is the Free Software +Foundation, then where a range of years appears, this is an inclusive +range that applies to every year in the range. For example: 2005-2008 +represents the years 2005, 2006, 2007, and 2008. + +Local Variables: +mode: outline +paragraph-separate: "[ ]*$" +version-control: never +End: |