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 device is now `stdin' on read and `stdout' on write.
  56 The installer can still override this by presetting `DEFAULT_ARCHIVE'
  57 in the environment before configuring (the behavior of `-[0-7]' or
  58 `-[0-7]lmh' options in `tar' are then derived automatically).  Similarly,
  59 `DEFAULT_BLOCKING' can be preset to something else than 20.
  60
  61 For comprehensive modifications to GNU tar, you might need tools beyond
  62 those used in simple installations.  Fully install GNU m4 1.4 first,
  63 and only then, Autoconf 2.57 or later.  Install Perl, then Automake
  64 1.7.5 or later.  Also, install gettext 0.12.1 or later.  You might
  65 need Bison 1.875 or later, and GNU tar itself.  All are available on
  66 GNU archive sites, like in ftp://ftp.gnu.org/pub/gnu/.
  67
  68 Send bug reports to <bug-tar@gnu.org>.  A bug report should contain
  69 an adequate description of the problem, your input, what you expected,
  70 what you got, and why this is wrong.  Diffs are welcome, but they only
  71 describe a solution, from which the problem might be uneasy to infer.
  72 If needed, submit actual data files with your report.  Small data files
  73 are preferred.  Big files may sometimes be necessary, but do not send them
  74 to the report address; rather take special arrangement with the maintainer.
  75
  76 Your feedback will help us to make a better and more portable package.
  77 Consider documentation errors as bugs, and report them as such.  If you
  78 develop anything pertaining to `tar' or have suggestions, let us know
  79 and share your findings by writing to <bug-tar@gnu.org>.
  80
  81
  82 Installation hints
  83 ------------------
  84
  85 Here are a few hints which might help installing `tar' on some systems.
  86
  87 * gzip and bzip2.
  88
  89 GNU tar uses the gzip and bzip2 programs to read and write compressed
  90 archives.  If you don't have these programs already, you need to
  91 install them.  Their sources can be found at:
  92
  93 ftp://ftp.gnu.org/gnu/gzip/
  94 http://sourceware.cygnus.com/bzip2/
  95
  96 If you see the following symptoms:
  97
  98    $ tar -xzf file.tar.gz
  99    gzip: stdin: decompression OK, trailing garbage ignored
 100    tar: Child returned status 2
 101
 102 then you have encountered a gzip incompatibility that should be fixed
 103 in gzip test version 1.3, which as of this writing is available at
 104 <ftp://alpha.gnu.org/gnu/gzip/>.  You can work around the
 105 incompatibility by using a shell command like
 106  `gzip -d <file.tar.gz | tar -xzf -'.
 107
 108 * Solaris issues.
 109
 110 GNU tar exercises many features that can cause problems with older GCC
 111 versions.  In particular, GCC 2.8.1 (sparc, -O1 or -O2) is known to
 112 miscompile GNU tar.  No compiler-related problems have been reported
 113 when using GCC 2.95.2 or later.
 114
 115 Recent versions of Solaris tar sport a new -E option to generate
 116 extended headers in an undocumented format.  GNU tar does not
 117 understand these headers.
 118
 119 * Static linking.
 120
 121 Some platform will, by default, prepare a smaller `tar' executable
 122 which depends on shared libraries.  Since GNU `tar' may be used for
 123 system-level backups and disaster recovery, installers might prefer to
 124 force static linking, making a bigger `tar' executable maybe, but able to
 125 work standalone, in situations where shared libraries are not available.
 126 The way to achieve static linking varies between systems.  Set LDFLAGS
 127 to a value from the table below, before configuration (see `INSTALL').
 128
 129         Platform        Compiler        LDFLAGS
 130
 131         (any)           Gnu C           -static
 132         AIX             (vendor)        -bnso -bI:/lib/syscalls.exp
 133         HPUX            (vendor)        -Wl,-a,archive
 134         IRIX            (vendor)        -non_shared
 135         OSF             (vendor)        -non_shared
 136         SCO 3.2v5       (vendor)        -dn
 137         Solaris         (vendor)        -Bstatic
 138         SunOS           (vendor)        -Bstatic
 139
 140 * Failed tests `ignfail.sh' or `incremen.sh'.
 141
 142 In an NFS environment, lack of synchronization between machine clocks
 143 might create difficulties to any tool comparing dates and file time stamps,
 144 like `tar' in incremental dumps.  This has been a recurrent problem with
 145 GNU Make for the last few years.  We would like a general solution.
 146
 147 * BSD compatibility matters.
 148
 149 Set LIBS to `-lbsd' before configuration (see `INSTALL') if the linker
 150 complains about `bsd_ioctl' (Slackware).  Also set CPPFLAGS to
 151 `-I/usr/include/bsd' if <sgtty.h> is not found (Slackware).
 152
 153 * OPENStep 4.2 swap files
 154
 155 Tar cannot read the file /private/vm/swapfile.front (even as root).
 156 This file is not a real file, but some kind of uncompressed view of
 157 the real compressed swap file; there is no reason to back it up, so
 158 the simplest workaround is to avoid tarring this file.
 159
 160
 161 Special topics
 162 --------------
 163
 164 Here are a few special matters about GNU `tar', not related to build
 165 matters.  See previous section for such.
 166
 167 * File attributes.
 168
 169 About *security*, it is probable that future releases of `tar' will have
 170 some behavior changed.  There are many pending suggestions to choose from.
 171 Today, extracting an archive not being `root', `tar' will restore suid/sgid
 172 bits on files but owned by the extracting user.  `root' automatically gets
 173 a lot of special privileges, `-p' might later become required to get them.
 174
 175 GNU `tar' does not properly restore symlink attributes.  Various systems
 176 implement flavors of symbolic links showing different behavior and
 177 properties.  We did not successfully sorted all these out yet.  Currently,
 178 the `lchown' call will be used if available, but that's all.
 179
 180 * POSIX compliance.
 181
 182 GNU `tar' implements an early draft of the POSIX 1003.1 `ustar' standard
 183 which is different from the final standard.  This will be progressively
 184 corrected over the incoming few years.  Don't be mislead by the mere
 185 existence of the --posix option.  Later releases will become able to
 186 read truly POSIX archives, and also to produce them under option.  (Also,
 187 if you look at the internals, don't take the GNU extensions you see for
 188 granted, as they are planned to change.)  GNU tar 2.0 will produce POSIX
 189 archives by default, but there is a long way before we get there.
 190
 191 * What's next?
 192
 193 In the future we will try to release tar-1.14 as soon as possible and
 194 start merging with paxutils afterwards.  We'll also try to rewrite
 195 some parts of the documentation after paxutils has been merged.