Dogcows Code - chaz/tar/blob - README

   1 README for GNU tar
   2
   3         Copyright (C) 1990, 1991, 1992, 1994, 1997, 1998, 1999, 2000,
   4         2001, 2003 Free Software Foundation, Inc.
   5
   6         This file is part of GNU tar.
   7
   8         GNU tar is free software; you can redistribute it and/or modify
   9         it under the terms of the GNU General Public License as published by
  10         the Free Software Foundation; either version 2, or (at your option)
  11         any later version.
  12
  13         GNU tar is distributed in the hope that it will be useful,
  14         but WITHOUT ANY WARRANTY; without even the implied warranty of
  15         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16         GNU General Public License for more details.
  17
  18         You should have received a copy of the GNU General Public License
  19         along with tar; see the file COPYING.  If not, write to
  20         the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21         Boston, MA 02111-1307, USA.
  22
  23
  24 Please glance through *all* sections of this
  25 `README' file before starting configuration.  Also make sure you read files
  26 `ABOUT-NLS' and `INSTALL' if you are not familiar with them already.
  27
  28 If you got the `tar' distribution in `shar' format, time stamps ought to be
  29 properly restored; do not ignore such complaints at `unshar' time.
  30
  31 GNU `tar' saves many files together into a single tape or disk
  32 archive, and can restore individual files from the archive.  It includes
  33 multivolume support, the ability to archive sparse files, automatic archive
  34 compression/decompression, remote archives and special features that allow
  35 `tar' to be used for incremental and full backups.  This distribution
  36 also includes `rmt', the remote tape server.  The `mt' tape drive control
  37 program is in the GNU `cpio' distribution.
  38
  39 GNU `tar' is derived from John Gilmore's public domain `tar'.
  40
  41 See file `ABOUT-NLS' for how to customize this program to your language.
  42 See file `COPYING' for copying conditions.
  43 See file `INSTALL' for compilation and installation instructions.
  44 See file `PORTS' for various ports of GNU tar to non-Unix systems.
  45 See file `NEWS' for a list of major changes in the current release.
  46 See file `THANKS' for a list of contributors.
  47
  48 Besides those configure options documented in files `INSTALL' and
  49 `ABOUT-NLS', an extra option may be accepted after `./configure':
  50
  51 * `--disable-largefile' omits support for large files, even if the
  52 operating system supports large files.  Typically, large files are
  53 those larger on 2 GB on a 32-bit host.
  54
  55 The default archive format is GNU, this can be overridden by
  56 presetting DEFAULT_ARCHIVE_FORMAT while configuring. The allowed
  57 values are GNU, V7, OLDGNU and POSIX.
  58
  59 The default archive device is now `stdin' on read and `stdout' on write.
  60 The installer can still override this by presetting `DEFAULT_ARCHIVE'
  61 in the environment before configuring (the behavior of `-[0-7]' or
  62 `-[0-7]lmh' options in `tar' are then derived automatically).  Similarly,
  63 `DEFAULT_BLOCKING' can be preset to something else than 20.
  64
  65 For comprehensive modifications to GNU tar, you might need tools beyond
  66 those used in simple installations.  Fully install GNU m4 1.4 first,
  67 and only then, Autoconf 2.57 or later.  Install Perl, then Automake
  68 1.7.5 or later.  Also, install gettext 0.12.1 or later.  You might
  69 need Bison 1.875 or later, and GNU tar itself.  All are available on
  70 GNU archive sites, like in ftp://ftp.gnu.org/pub/gnu/.
  71
  72 Send bug reports to <bug-tar@gnu.org>.  A bug report should contain
  73 an adequate description of the problem, your input, what you expected,
  74 what you got, and why this is wrong.  Diffs are welcome, but they only
  75 describe a solution, from which the problem might be uneasy to infer.
  76 If needed, submit actual data files with your report.  Small data files
  77 are preferred.  Big files may sometimes be necessary, but do not send them
  78 to the report address; rather take special arrangement with the maintainer.
  79
  80 Your feedback will help us to make a better and more portable package.
  81 Consider documentation errors as bugs, and report them as such.  If you
  82 develop anything pertaining to `tar' or have suggestions, let us know
  83 and share your findings by writing to <bug-tar@gnu.org>.
  84
  85
  86 Installation hints
  87 ------------------
  88
  89 Here are a few hints which might help installing `tar' on some systems.
  90
  91 * gzip and bzip2.
  92
  93 GNU tar uses the gzip and bzip2 programs to read and write compressed
  94 archives.  If you don't have these programs already, you need to
  95 install them.  Their sources can be found at:
  96
  97 ftp://ftp.gnu.org/gnu/gzip/
  98 http://sourceware.cygnus.com/bzip2/
  99
 100 If you see the following symptoms:
 101
 102    $ tar -xzf file.tar.gz
 103    gzip: stdin: decompression OK, trailing garbage ignored
 104    tar: Child returned status 2
 105
 106 then you have encountered a gzip incompatibility that should be fixed
 107 in gzip test version 1.3, which as of this writing is available at
 108 <ftp://alpha.gnu.org/gnu/gzip/>.  You can work around the
 109 incompatibility by using a shell command like
 110  `gzip -d <file.tar.gz | tar -xzf -'.
 111
 112 * Solaris issues.
 113
 114 GNU tar exercises many features that can cause problems with older GCC
 115 versions.  In particular, GCC 2.8.1 (sparc, -O1 or -O2) is known to
 116 miscompile GNU tar.  No compiler-related problems have been reported
 117 when using GCC 2.95.2 or later.
 118
 119 Recent versions of Solaris tar sport a new -E option to generate
 120 extended headers in an undocumented format.  GNU tar does not
 121 understand these headers.
 122
 123 * Static linking.
 124
 125 Some platform will, by default, prepare a smaller `tar' executable
 126 which depends on shared libraries.  Since GNU `tar' may be used for
 127 system-level backups and disaster recovery, installers might prefer to
 128 force static linking, making a bigger `tar' executable maybe, but able to
 129 work standalone, in situations where shared libraries are not available.
 130 The way to achieve static linking varies between systems.  Set LDFLAGS
 131 to a value from the table below, before configuration (see `INSTALL').
 132
 133         Platform        Compiler        LDFLAGS
 134
 135         (any)           Gnu C           -static
 136         AIX             (vendor)        -bnso -bI:/lib/syscalls.exp
 137         HPUX            (vendor)        -Wl,-a,archive
 138         IRIX            (vendor)        -non_shared
 139         OSF             (vendor)        -non_shared
 140         SCO 3.2v5       (vendor)        -dn
 141         Solaris         (vendor)        -Bstatic
 142         SunOS           (vendor)        -Bstatic
 143
 144 * Failed tests `ignfail.sh' or `incremen.sh'.
 145
 146 In an NFS environment, lack of synchronization between machine clocks
 147 might create difficulties to any tool comparing dates and file time stamps,
 148 like `tar' in incremental dumps.  This has been a recurrent problem with
 149 GNU Make for the last few years.  We would like a general solution.
 150
 151 * BSD compatibility matters.
 152
 153 Set LIBS to `-lbsd' before configuration (see `INSTALL') if the linker
 154 complains about `bsd_ioctl' (Slackware).  Also set CPPFLAGS to
 155 `-I/usr/include/bsd' if <sgtty.h> is not found (Slackware).
 156
 157 * OPENStep 4.2 swap files
 158
 159 Tar cannot read the file /private/vm/swapfile.front (even as root).
 160 This file is not a real file, but some kind of uncompressed view of
 161 the real compressed swap file; there is no reason to back it up, so
 162 the simplest workaround is to avoid tarring this file.
 163
 164
 165 Special topics
 166 --------------
 167
 168 Here are a few special matters about GNU `tar', not related to build
 169 matters.  See previous section for such.
 170
 171 * File attributes.
 172
 173 About *security*, it is probable that future releases of `tar' will have
 174 some behavior changed.  There are many pending suggestions to choose from.
 175 Today, extracting an archive not being `root', `tar' will restore suid/sgid
 176 bits on files but owned by the extracting user.  `root' automatically gets
 177 a lot of special privileges, `-p' might later become required to get them.
 178
 179 GNU `tar' does not properly restore symlink attributes.  Various systems
 180 implement flavors of symbolic links showing different behavior and
 181 properties.  We did not successfully sorted all these out yet.  Currently,
 182 the `lchown' call will be used if available, but that's all.
 183
 184 * POSIX compliance.
 185
 186 GNU `tar' implements an early draft of the POSIX 1003.1 `ustar' standard
 187 which is different from the final standard.  This will be progressively
 188 corrected over the incoming few years.  Don't be mislead by the mere
 189 existence of the --posix option.  Later releases will become able to
 190 read truly POSIX archives, and also to produce them under option.  (Also,
 191 if you look at the internals, don't take the GNU extensions you see for
 192 granted, as they are planned to change.)  GNU tar 2.0 will produce POSIX
 193 archives by default, but there is a long way before we get there.
 194
 195 * What's next?
 196
 197 In the future we will try to release tar-1.14 as soon as possible and
 198 start merging with paxutils afterwards.  We'll also try to rewrite
 199 some parts of the documentation after paxutils has been merged.