2 See the end of file for copying conditions.
6 Please glance through *all* sections of this
7 'README' file before starting configuration. Also make sure you read files
8 'ABOUT-NLS' and 'INSTALL' if you are not familiar with them already.
10 If you got the 'tar' distribution in 'shar' format, time stamps ought to be
11 properly restored; do not ignore such complaints at 'unshar' time.
13 GNU 'tar' saves many files together into a single tape or disk
14 archive, and can restore individual files from the archive. It includes
15 multivolume support, the ability to archive sparse files, automatic archive
16 compression/decompression, remote archives and special features that allow
17 'tar' to be used for incremental and full backups. This distribution
18 also includes 'rmt', the remote tape server. The 'mt' tape drive control
19 program is in the GNU 'cpio' distribution.
21 GNU 'tar' is derived from John Gilmore's public domain 'tar'.
23 See file 'ABOUT-NLS' for how to customize this program to your language.
24 See file 'COPYING' for copying conditions.
25 See file 'INSTALL' for compilation and installation instructions.
26 See file 'NEWS' for a list of major changes in the current release.
27 See file 'THANKS' for a list of contributors.
29 Besides those configure options documented in files 'INSTALL' and
30 'ABOUT-NLS', an extra option may be accepted after './configure':
34 ** Selecting the default archive format.
36 The default archive format is GNU, this can be overridden by
37 presetting DEFAULT_ARCHIVE_FORMAT while configuring. The allowed
38 values are GNU, V7, OLDGNU, USTAR and POSIX.
40 ** Selecting the default archive device
42 The default archive device is now 'stdin' on read and 'stdout' on write.
43 The installer can still override this by presetting 'DEFAULT_ARCHIVE'
44 in the environment before configuring (the behavior of '-[0-7]' or
45 '-[0-7]lmh' options in 'tar' are then derived automatically). Similarly,
46 'DEFAULT_BLOCKING' can be preset to something else than 20.
48 ** Selecting full pathname of the "rmt" binary.
50 Previous versions of tar always looked for "rmt" binary in the
51 directory "/etc/rmt". However, the "rmt" program included
52 in the distribution was installed under "$prefix/libexec/rmt".
53 To fix this discrepancy, tar now looks for "$prefix/libexec/rmt".
54 If you do not want this behavior, specify full path name of
55 "rmt" binary using DEFAULT_RMT_DIR variable, e.g.:
57 ./configure DEFAULT_RMT_DIR=/etc
59 If you already have a copy of "rmt" installed and wish to use it
60 instead of the version supplied with the distribution, use --with-rmt
63 ./configure --with-rmt=/etc/rmt
65 This will also disable building the included version of rmt.
67 ** Installing backup scripts.
69 This version of tar is shipped with the shell scripts for producing
70 incremental backups (dumps) and restoring filesystems from them.
71 The name of the backup script is "backup". The name of the
72 restore script is "restore". They are installed in "$prefix/sbin"
75 Use option --enable-backup-scripts to compile and install these
78 ** '--disable-largefile' omits support for large files, even if the
79 operating system supports large files. Typically, large files are
80 those larger than 2 GB on a 32-bit host.
84 Here are a few hints which might help installing 'tar' on some systems.
88 GNU tar uses the gzip and bzip2 programs to read and write compressed
89 archives. If you don't have these programs already, you need to
90 install them. Their sources can be found at:
92 ftp://ftp.gnu.org/gnu/gzip/
93 http://sourceware.cygnus.com/bzip2/
95 If you see the following symptoms:
97 $ tar -xzf file.tar.gz
98 gzip: stdin: decompression OK, trailing garbage ignored
99 tar: Child returned status 2
101 then you have encountered a gzip incompatibility that should be fixed
102 in gzip test version 1.3, which as of this writing is available at
103 <ftp://alpha.gnu.org/gnu/gzip/>. You can work around the
104 incompatibility by using a shell command like
105 'gzip -d <file.tar.gz | tar -xzf -'.
109 GNU tar exercises many features that can cause problems with older GCC
110 versions. In particular, GCC 2.8.1 (sparc, -O1 or -O2) is known to
111 miscompile GNU tar. No compiler-related problems have been reported
112 when using GCC 2.95.2 or later.
114 Recent versions of Solaris tar sport a new -E option to generate
115 extended headers in an undocumented format. GNU tar does not
116 understand these headers.
120 Some platform will, by default, prepare a smaller 'tar' executable
121 which depends on shared libraries. Since GNU 'tar' may be used for
122 system-level backups and disaster recovery, installers might prefer to
123 force static linking, making a bigger 'tar' executable maybe, but able to
124 work standalone, in situations where shared libraries are not available.
125 The way to achieve static linking varies between systems. Set LDFLAGS
126 to a value from the table below, before configuration (see 'INSTALL').
128 Platform Compiler LDFLAGS
131 AIX (vendor) -bnso -bI:/lib/syscalls.exp
132 HPUX (vendor) -Wl,-a,archive
133 IRIX (vendor) -non_shared
134 OSF (vendor) -non_shared
135 SCO 3.2v5 (vendor) -dn
136 Solaris (vendor) -Bstatic
137 SunOS (vendor) -Bstatic
139 ** Failed tests 'ignfail.sh' or 'incremen.sh'.
141 In an NFS environment, lack of synchronization between machine clocks
142 might create difficulties to any tool comparing dates and file time stamps,
143 like 'tar' in incremental dumps. This has been a recurrent problem with
144 GNU Make for the last few years. We would like a general solution.
146 ** BSD compatibility matters.
148 Set LIBS to '-lbsd' before configuration (see 'INSTALL') if the linker
149 complains about 'bsd_ioctl' (Slackware). Also set CPPFLAGS to
150 '-I/usr/include/bsd' if <sgtty.h> is not found (Slackware).
152 ** OPENStep 4.2 swap files
154 Tar cannot read the file /private/vm/swapfile.front (even as root).
155 This file is not a real file, but some kind of uncompressed view of
156 the real compressed swap file; there is no reason to back it up, so
157 the simplest workaround is to avoid tarring this file.
161 Here are a few special matters about GNU 'tar', not related to build
162 matters. See previous section for such.
166 About *security*, it is probable that future releases of 'tar' will have
167 some behavior changed. There are many pending suggestions to choose from.
168 Today, extracting an archive not being 'root', 'tar' will restore suid/sgid
169 bits on files but owned by the extracting user. 'root' automatically gets
170 a lot of special privileges, '-p' might later become required to get them.
172 GNU 'tar' does not properly restore symlink attributes. Various systems
173 implement flavors of symbolic links showing different behavior and
174 properties. We did not successfully sorted all these out yet. Currently,
175 the 'lchown' call will be used if available, but that's all.
179 GNU 'tar' is able to create archive in the following formats:
181 *** The format of UNIX version 7
182 *** POSIX.1-1988 format, also known as "ustar format"
183 *** POSIX.1-2001 format, also known as "pax format"
184 *** Old GNU format (described below)
186 In addition to those, GNU 'tar' is also able to read archives
187 produced by 'star' archiver.
189 A so called 'Old GNU' format is based on an early draft of the
190 POSIX 1003.1 'ustar' standard which is different from the final
191 standard. It defines its extensions (such as incremental backups
192 and handling of the long file names) in a way incompatible with
193 any existing tar archive format, therefore the use of old GNU
194 format is strongly discouraged.
196 Please read the file NEWS for more information about POSIX compliance
197 and new 'tar' features.
201 GNU tar will be merged into GNU paxutils: a project containing
202 several utilities related to creating and handling archives in
203 various formats. The project will include tar, cpio and pax
208 Send bug reports to <bug-tar@gnu.org>. A bug report should contain
209 an adequate description of the problem, your input, what you expected,
210 what you got, and why this is wrong. Diffs are welcome, but they only
211 describe a solution, from which the problem might be uneasy to infer.
212 If needed, submit actual data files with your report. Small data files
213 are preferred. Big files may sometimes be necessary, but do not send them
214 to the report address; rather take special arrangement with the maintainer.
216 Your feedback will help us to make a better and more portable package.
217 Consider documentation errors as bugs, and report them as such. If you
218 develop anything pertaining to 'tar' or have suggestions, let us know
219 and share your findings by writing to <bug-tar@gnu.org>.
224 Copyright 1990-2020 Free Software Foundation, Inc.
226 This file is part of GNU tar.
228 GNU tar is free software; you can redistribute it and/or modify
229 it under the terms of the GNU General Public License as published by
230 the Free Software Foundation; either version 3 of the License, or
231 (at your option) any later version.
233 GNU tar is distributed in the hope that it will be useful,
234 but WITHOUT ANY WARRANTY; without even the implied warranty of
235 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
236 GNU General Public License for more details.
238 You should have received a copy of the GNU General Public License
239 along with this program. If not, see <http://www.gnu.org/licenses/>.
241 NOTE ON COPYRIGHT YEARS
243 In copyright notices where the copyright holder is the Free Software
244 Foundation, then where a range of years appears, this is an inclusive
245 range that applies to every year in the range. For example: 2005-2008
246 represents the years 2005, 2006, 2007, and 2008.
250 paragraph-separate: "[
\f]*$"
251 version-control: never