Dogcows Code - chaz/tar/blob - README

   1 Please glance through *all* sections of this
   2 `README' file before starting configuration.  Also make sure you read files
   3 `ABOUT-NLS' and `INSTALL' if you are not familiar with them already.
   4
   5 If you got the `tar' distribution in `shar' format, time stamps ought to be
   6 properly restored; do not ignore such complaints at `unshar' time.
   7
   8 GNU `tar' saves many files together into a single tape or disk
   9 archive, and can restore individual files from the archive.  It includes
  10 multivolume support, the ability to archive sparse files, automatic archive
  11 compression/decompression, remote archives and special features that allow
  12 `tar' to be used for incremental and full backups.  This distribution
  13 also includes `rmt', the remote tape server.  The `mt' tape drive control
  14 program is in the GNU `cpio' distribution.
  15
  16 GNU `tar' is derived from John Gilmore's public domain `tar'.
  17
  18 See file `ABOUT-NLS' for how to customize this program to your language.
  19 See file `COPYING' for copying conditions.
  20 See file `INSTALL' for compilation and installation instructions.
  21 See file `PORTS' for various ports of GNU tar to non-Unix systems.
  22 See file `NEWS' for a list of major changes in the current release.
  23 See file `THANKS' for a list of contributors.
  24
  25 Besides those configure options documented in files `INSTALL' and
  26 `ABOUT-NLS', an extra option may be accepted after `./configure':
  27
  28 * `--disable-largefile' omits support for large files, even if the
  29 operating system supports large files.  Typically, large files are
  30 those larger on 2 GB on a 32-bit host.
  31
  32 The default archive device is now `stdin' on read and `stdout' on write.
  33 The installer can still override this by presetting `DEFAULT_ARCHIVE'
  34 in the environment before configuring (the behavior of `-[0-7]' or
  35 `-[0-7]lmh' options in `tar' are then derived automatically).  Similarly,
  36 `DEFAULT_BLOCKING' can be preset to something else than 20.
  37
  38 For comprehensive modifications to GNU tar, you might need tools beyond
  39 those used in simple installations.  Fully install GNU m4 1.4 first,
  40 and only then, Autoconf 2.13 or later.  Install Perl, then Automake
  41 1.4 or later.  You might need Bison 1.28 or later, and GNU tar itself.
  42 All are available on GNU archive sites, like in
  43 ftp://ftp.gnu.org/pub/gnu/.
  44
  45 Send bug reports to `bug-tar@gnu.org'.  (Beware, old-timers: it is
  46 `@gnu', not `@prep'; and not `bug-gnu-utils' anymore.)  A bug report is
  47 an adequate description of the problem: your input, what you expected,
  48 what you got, and why this is wrong.  Diffs are welcome, but they only
  49 describe a solution, from which the problem might be uneasy to infer.
  50 If needed, submit actual data files with your report.  Small data files
  51 are preferred.  Big files may sometimes be necessary, but do not send them
  52 to the report address; rather take special arrangement with the maintainer.
  53
  54 Your feedback will help us to make a better and more portable package.
  55 Consider documentation errors as bugs, and report them as such.  If you
  56 develop anything pertaining to `tar' or have suggestions, let us know
  57 and share your findings by writing at `tar-forum@iro.umontreal.ca'.
  58
  59 .--------------------.
  60 | Installation hints |
  61 `--------------------'
  62
  63 Here are a few hints which might help installing `tar' on some systems.
  64
  65 * gzip and bzip2.
  66
  67 GNU tar uses the gzip and bzip2 programs to read and write compressed
  68 archives.  If you don't have these programs already, you need to
  69 install them.  Their sources can be found at:
  70
  71 ftp://ftp.gnu.org/gnu/gzip/
  72 http://sourceware.cygnus.com/bzip2/
  73
  74 If you see the following symptoms:
  75
  76    $ tar -xzf file.tar.gz
  77    gzip: stdin: decompression OK, trailing garbage ignored
  78    tar: Child returned status 2
  79
  80 then you have encountered a gzip incompatibility that should be fixed
  81 in gzip 1.3, which is not yet available as of this writing.  You can
  82 work around the incompatibility by using a shell command like
  83 `gzip -d <file.tar.gz | tar -xzf -'.
  84
  85 * Solaris issues.
  86
  87 If you are compiling with GCC, you may need to upgrade GCC to 2.95.2
  88 or later before compiling GNU tar, as GNU tar exercises many features
  89 that can cause problems with older GCC versions, mostly having to do
  90 with mutations to Solaris system include files.
  91
  92 Recent versions of Solaris tar sport a new -E option to generate
  93 extended headers in an undocumented format.  GNU tar does not
  94 understand these headers.
  95
  96 * Static linking.
  97
  98 Some platform will, by default, prepare a smaller `tar' executable
  99 which depends on shared libraries.  Since GNU `tar' may be used for
 100 system-level backups and disaster recovery, installers might prefer to
 101 force static linking, making a bigger `tar' executable maybe, but able to
 102 work standalone, in situations where shared libraries are not available.
 103 The way to achieve static linking varies between systems.  Set LDFLAGS
 104 to a value from the table below, before configuration (see `INSTALL').
 105
 106         Platform        Compiler        LDFLAGS
 107
 108         (any)           Gnu C           -static
 109         AIX             (vendor)        "-bnso -bI:/lib/syscalls.exp"
 110         HPUX            (vendor)        -Wl,-a,archive
 111         IRIX            (vendor)        -non_shared
 112         OSF             (vendor)        -non_shared
 113         SCO 3.2v5       (vendor)        -dn
 114         Solaris         (vendor)        -Bstatic
 115         SunOS           (vendor)        -Bstatic
 116
 117 * Failed `incremen.sh'.
 118
 119 In an NFS environment, lack of synchronization between machine clocks
 120 might create difficulties to any tool comparing dates and file time stamps,
 121 like `tar' in incremental dumps.  This has been a recurrent problem in
 122 GNU Makefiles for the last few years.  We would like a general solution.
 123
 124 * BSD compatibility matters.
 125
 126 Set LIBS to `-lbsd' before configuration (see `INSTALL') if the linker
 127 complains about `bsd_ioctl' (Slackware).  Also set CPPFLAGS to
 128 `-I/usr/include/bsd' if <sgtty.h> is not found (Slackware).
 129
 130 * OPENStep 4.2 swap files
 131
 132 Tar cannot read the file /private/vm/swapfile.front (even as root).
 133 This file is not a real file, but some kind of uncompressed view of
 134 the real compressed swap file; there is no reason to back it up, so
 135 the simplest workaround is to avoid tarring this file.
 136
 137 .------------------.
 138 | Special topics.  |
 139 `------------------'
 140
 141 Here are a few special matters about GNU `tar', not related to build
 142 matters.  See previous section for such.
 143
 144 * File attributes.
 145
 146 About *security*, it is probable that future releases of `tar' will have
 147 some behavior changed.  There are many pending suggestions to choose from.
 148 Today, extracting an archive not being `root', `tar' will restore suid/sgid
 149 bits on files but owned by the extracting user.  `root' automatically gets
 150 a lot of special privileges, `-p' might later become required to get them.
 151
 152 GNU `tar' does not properly restore symlink attributes.  Various systems
 153 implement flavors of symbolic links showing different behavior and
 154 properties.  We did not successfully sorted all these out yet.  Currently,
 155 the `lchown' call will be used if available, but that's all.
 156
 157 * POSIX compliance.
 158
 159 GNU `tar' implements an early draft of the POSIX 1003.1 `ustar' standard
 160 which is different from the final standard.  This will be progressively
 161 corrected over the incoming few years.  Don't be mislead by the mere
 162 existence of the --posix option.  Later releases will become able to
 163 read truly POSIX archives, and also to produce them under option.  (Also,
 164 if you look at the internals, don't take the GNU extensions you see for
 165 granted, as they are planned to change.)  GNU tar 2.0 will produce POSIX
 166 archives by default, but there is a long way before we get there.
 167
 168 * What's next?
 169
 170 In the future we will try to release tar-1.14 as soon as possible and
 171 start merging with paxutils afterwards.  We'll also try to rewrite
 172 some parts of the documentation after paxutils has been merged.