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Version 1.23.90

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* NEWS, configure.ac: Version 1.23.90
* doc/tar.texi: Document the use of lbzip2.
This commit is contained in:
Sergey Poznyakoff
2010-07-11 19:36:43 +03:00
parent 9c194c9942
commit b4bcb97e38
3 changed files with 134 additions and 74 deletions
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1
NEWS
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@@ -2,6 +2,7 @@ GNU tar NEWS - User visible changes. 2010-03-28
Please send GNU tar bug reports to <bug-tar@gnu.org>
version 1.23.90 - (Git)
* The --full-time option.

2
configure.ac
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@@ -19,7 +19,7 @@
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
AC_INIT([GNU tar], [1.23], [bug-tar@gnu.org])
AC_INIT([GNU tar], [1.23.90], [bug-tar@gnu.org])
AC_CONFIG_SRCDIR([src/tar.c])
AC_CONFIG_AUX_DIR([build-aux])
AC_CONFIG_HEADERS([config.h])

205
doc/tar.texi
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@@ -330,6 +330,10 @@ Using Less Space through Compression
* gzip:: Creating and Reading Compressed Archives
* sparse:: Archiving Sparse Files
Creating and Reading Compressed Archives
* lbzip2:: Using lbzip2 with @GNUTAR{}.
Making @command{tar} Archives More Portable
* Portable Names:: Portable Names
@@ -8701,7 +8705,7 @@ For example:
$ @kbd{tar cfz archive.tar.gz .}
@end smallexample
You can also let @GNUTAR{} select the compression program basing on
You can also let @GNUTAR{} select the compression program based on
the suffix of the archive file name. This is done using
@option{--auto-compress} (@option{-a}) command line option. For
example, the following invocation will use @command{bzip2} for
@@ -8766,7 +8770,94 @@ cannot append another @command{tar} archive to a compressed archive using
@option{--concatenate} (@option{-A}). Secondly, multi-volume
archives cannot be compressed.
The following table summarizes compression options used by @GNUTAR{}.
The following options allow to select a particular compressor program:
@table @option
@opindex gzip
@opindex ungzip
@item -z
@itemx --gzip
@itemx --ungzip
Filter the archive through @command{gzip}.
@opindex xz
@item -J
@itemx --xz
Filter the archive through @code{xz}.
@item -j
@itemx --bzip2
Filter the archive through @code{bzip2}.
@opindex lzip
@item --lzip
Filter the archive through @command{lzip}.
@opindex lzma
@item --lzma
Filter the archive through @command{lzma}.
@opindex lzop
@item --lzop
Filter the archive through @command{lzop}.
@opindex compress
@opindex uncompress
@item -Z
@itemx --compress
@itemx --uncompress
Filter the archive through @command{compress}.
@end table
When any of these options is given, @GNUTAR{} searches the compressor
binary in the current path and invokes it. The name of the compressor
program is specified at compilation time using a corresponding
@option{--with-@var{compname}} option to @command{configure}, e.g.
@option{--with-bzip2} to select a specific @command{bzip2} binary.
@xref{lbzip2}, for a detailed discussion.
The output produced by @command{tar --help} shows the actual
compressor names along with each of these options.
You can use any of these options on physical devices (tape drives,
etc.) and remote files as well as on normal files; data to or from
such devices or remote files is reblocked by another copy of the
@command{tar} program to enforce the specified (or default) record
size. The default compression parameters are used. Most compression
programs allow to override these by setting a program-specific
environment variable. For example, when using @command{gzip} you can
use @env{GZIP} as in the example below:
@smallexample
$ @kbd{GZIP=--best tar cfz archive.tar.gz subdir}
@end smallexample
@noindent
Another way would be to use the @option{-I} option instead (see
below), e.g.:
@smallexample
$ @kbd{tar -cf archive.tar.gz -I 'gzip --best' subdir}
@end smallexample
@noindent
Finally, the third, traditional, way to achieve the same result is to
use pipe:
@smallexample
$ @kbd{tar cf - subdir | gzip --best -c - > archive.tar.gz}
@end smallexample
@cindex corrupted archives
About corrupted compressed archives: compressed files have no
redundancy, for maximum compression. The adaptive nature of the
compression scheme means that the compression tables are implicitly
spread all over the archive. If you lose a few blocks, the dynamic
construction of the compression tables becomes unsynchronized, and there
is little chance that you could recover later in the archive.
Another compression options provide a better control over creating
compressed archives. These are:
@table @option
@anchor{auto-compress}
@@ -8794,77 +8885,6 @@ suffix. The following suffixes are recognized:
@item @samp{.xz} @tab @command{xz}
@end multitable
@opindex gzip
@opindex ungzip
@item -z
@itemx --gzip
@itemx --ungzip
Filter the archive through @command{gzip}.
You can use @option{--gzip} and @option{--gunzip} on physical devices
(tape drives, etc.) and remote files as well as on normal files; data
to or from such devices or remote files is reblocked by another copy
of the @command{tar} program to enforce the specified (or default) record
size. The default compression parameters are used; if you need to
override them, set @env{GZIP} environment variable, e.g.:
@smallexample
$ @kbd{GZIP=--best tar cfz archive.tar.gz subdir}
@end smallexample
@noindent
Another way would be to avoid the @option{--gzip} (@option{--gunzip}, @option{--ungzip}, @option{-z}) option and run
@command{gzip} explicitly:
@smallexample
$ @kbd{tar cf - subdir | gzip --best -c - > archive.tar.gz}
@end smallexample
@cindex corrupted archives
About corrupted compressed archives: @command{gzip}'ed files have no
redundancy, for maximum compression. The adaptive nature of the
compression scheme means that the compression tables are implicitly
spread all over the archive. If you lose a few blocks, the dynamic
construction of the compression tables becomes unsynchronized, and there
is little chance that you could recover later in the archive.
There are pending suggestions for having a per-volume or per-file
compression in @GNUTAR{}. This would allow for viewing the
contents without decompression, and for resynchronizing decompression at
every volume or file, in case of corrupted archives. Doing so, we might
lose some compressibility. But this would have make recovering easier.
So, there are pros and cons. We'll see!
@opindex bzip2
@item -J
@itemx --xz
Filter the archive through @code{xz}. Otherwise like
@option{--gzip}.
@item -j
@itemx --bzip2
Filter the archive through @code{bzip2}. Otherwise like @option{--gzip}.
@opindex lzip
@item --lzip
Filter the archive through @command{lzip}. Otherwise like @option{--gzip}.
@opindex lzma
@item --lzma
Filter the archive through @command{lzma}. Otherwise like @option{--gzip}.
@opindex lzop
@item --lzop
Filter the archive through @command{lzop}. Otherwise like
@option{--gzip}.
@opindex compress
@opindex uncompress
@item -Z
@itemx --compress
@itemx --uncompress
Filter the archive through @command{compress}. Otherwise like @option{--gzip}.
@opindex use-compress-program
@item --use-compress-program=@var{prog}
@itemx -I=@var{prog}
@@ -8957,6 +8977,45 @@ The above is based on the following discussion:
end up with less space on the tape.
@end ignore
@menu
* lbzip2:: Using lbzip2 with @GNUTAR{}.
@end menu
@node lbzip2
@subsubsection Using lbzip2 with @GNUTAR{}.
@cindex lbzip2
@cindex Laszlo Ersek
@command{Lbzip2} is a multithreaded utility for handling
@samp{bzip2} compression, written by Laszlo Ersek. It makes use of
multiple processors to speed up its operation and in general works
considerably faster than @command{bzip2}. For a detailed description
of @command{lbzip2} see @uref{http://freshmeat.net/@/projects/@/lbzip2} and
@uref{http://www.linuxinsight.com/@/lbzip2-parallel-bzip2-utility.html,
lbzip2: parallel bzip2 utility}.
Recent versions of @command{lbzip2} are mostly command line compatible
with @command{bzip2}, which makes it possible to automatically invoke
it via the @option{--bzip2} @GNUTAR{} command line option. To do so,
@GNUTAR{} must be configured with the @option{--with-bzip2} command
line option, like this:
@smallexample
$ @kbd{./configure --with-bzip2=lbzip2 [@var{other-options}]}
@end smallexample
Once configured and compiled this way, @command{tar --help} will show the
following:
@smallexample
@group
$ @kbd{tar --help | grep -- --bzip2}
-j, --bzip2 filter the archive through lbzip2
@end group
@end smallexample
@noindent
which means that running @command{tar --bzip2} will invoke @command{lbzip2}.
@node sparse
@subsection Archiving Sparse Files
@cindex Sparse Files