Dogcows Code - chaz/tar/blob - README

   1 README for GNU tar
   2 See the end of file for copying conditions.
   3
   4 * Introduction
   5
   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.
   9
  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.
  12
  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.
  20
  21 GNU 'tar' is derived from John Gilmore's public domain 'tar'.
  22
  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.
  28
  29 Besides those configure options documented in files 'INSTALL' and
  30 'ABOUT-NLS', an extra option may be accepted after './configure':
  31
  32 * Install
  33
  34 ** Selecting the default archive format.
  35
  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.
  39
  40 ** Selecting the default archive device
  41
  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.
  47
  48 ** Selecting full pathname of the "rmt" binary.
  49
  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.:
  56
  57 ./configure DEFAULT_RMT_DIR=/etc
  58
  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
  61 option:
  62
  63 ./configure --with-rmt=/etc/rmt
  64
  65 This will also disable building the included version of rmt.
  66
  67 ** Installing backup scripts.
  68
  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"
  73 directory.
  74
  75 Use option --enable-backup-scripts to compile and install these
  76 scripts.
  77
  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.
  81
  82 * Installation hints
  83
  84 Here are a few hints which might help installing 'tar' on some systems.
  85
  86 ** gzip and bzip2.
  87
  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:
  91
  92 ftp://ftp.gnu.org/gnu/gzip/
  93 http://sourceware.cygnus.com/bzip2/
  94
  95 If you see the following symptoms:
  96
  97    $ tar -xzf file.tar.gz
  98    gzip: stdin: decompression OK, trailing garbage ignored
  99    tar: Child returned status 2
 100
 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 -'.
 106
 107 ** Solaris issues.
 108
 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.
 113
 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.
 117
 118 ** Static linking.
 119
 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').
 127
 128         Platform        Compiler        LDFLAGS
 129
 130         (any)           Gnu C           -static
 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
 138
 139 ** Failed tests 'ignfail.sh' or 'incremen.sh'.
 140
 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.
 145
 146 ** BSD compatibility matters.
 147
 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).
 151
 152 ** OPENStep 4.2 swap files
 153
 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.
 158
 159 * Special topics
 160
 161 Here are a few special matters about GNU 'tar', not related to build
 162 matters.  See previous section for such.
 163
 164 ** File attributes.
 165
 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.
 171
 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.
 176
 177 ** POSIX compliance.
 178
 179 GNU 'tar' is able to create archive in the following formats:
 180
 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)
 185
 186 In addition to those, GNU 'tar' is also able to read archives
 187 produced by 'star' archiver.
 188
 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.
 195
 196 Please read the file NEWS for more information about POSIX compliance
 197 and new 'tar' features.
 198
 199 * What's next?
 200
 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
 204 utilities.
 205
 206 * Bug reporting.
 207
 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.
 215
 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>.
 220
 221 \f
 222 * Copying
 223
 224 Copyright 1990-1992, 1994, 1997-2001, 2003-2004, 2007, 2012-2014 Free
 225 Software Foundation, Inc.
 226
 227 This file is part of GNU tar.
 228
 229 GNU tar is free software; you can redistribute it and/or modify
 230 it under the terms of the GNU General Public License as published by
 231 the Free Software Foundation; either version 3 of the License, or
 232 (at your option) any later version.
 233
 234 GNU tar is distributed in the hope that it will be useful,
 235 but WITHOUT ANY WARRANTY; without even the implied warranty of
 236 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 237 GNU General Public License for more details.
 238
 239 You should have received a copy of the GNU General Public License
 240 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 241
 242 NOTE ON COPYRIGHT YEARS
 243
 244 In copyright notices where the copyright holder is the Free Software
 245 Foundation, then where a range of years appears, this is an inclusive
 246 range that applies to every year in the range.  For example: 2005-2008
 247 represents the years 2005, 2006, 2007, and 2008.
 248 \f
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 250 mode: outline
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