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[Lzip-bug] Tarlz 0.7 released


From: Antonio Diaz Diaz
Subject: [Lzip-bug] Tarlz 0.7 released
Date: Sun, 25 Nov 2018 23:14:57 +0100
User-agent: Mozilla/5.0 (X11; U; Linux i586; en-US; rv:1.9.1.19) Gecko/20110420 SeaMonkey/2.0.14

I am pleased to announce the release of tarlz 0.7.

Tarlz is a small and simple implementation of the tar archiver. By default tarlz creates, lists and extracts archives in a simplified posix pax format compressed with lzip on a per file basis. Each tar member is compressed in its own lzip member, as well as the end-of-file blocks. This method is fully backward compatible with standard tar tools like GNU tar, which treat the resulting multimember tar.lz archive like any other tar.lz archive. Tarlz can append files to the end of such compressed archives.

Tarlz can create tar archives with four levels of compression granularity; per file, per directory, appendable solid, and solid.

Of course, compressing each file (or each directory) individually is less efficient than compressing the whole tar archive, but it has the following advantages:

   * The resulting multimember tar.lz archive can be decompressed in
     parallel with plzip, multiplying the decompression speed.

   * New members can be appended to the archive (by removing the EOF
     member) just like to an uncompressed tar archive.

   * It is a safe posix-style backup format. In case of corruption,
     tarlz can extract all the undamaged members from the tar.lz
     archive, skipping over the damaged members, just like the standard
     (uncompressed) tar. Moreover, the option '--keep-damaged' can be
     used to recover as much data as possible from each damaged member,
     and lziprecover can be used to recover some of the damaged members.

   * A multimember tar.lz archive is usually smaller than the
     corresponding solidly compressed tar.gz archive, except when
     individually compressing files smaller than about 32 KiB.

Note that the posix pax format has a serious flaw. The metadata stored in pax extended records are not protected by any kind of check sequence. Because of this, tarlz protects the extended records with a CRC in a way compatible with standard tar tools.

The homepage is at http://www.nongnu.org/lzip/tarlz.html

An online manual for tarlz can be found at http://www.nongnu.org/lzip/manual/tarlz_manual.html

The sources can be downloaded from
http://download.savannah.gnu.org/releases/lzip/tarlz/tarlz-0.7.tar.lz

The sha256sum is:
548f3b80596a5f84f1c652d504cd95b6fc19789de3a1a3b9a52f5146a42acff6 tarlz-0.7.tar.lz


Changes in version 0.7:

* The new option '--keep-damaged', which keeps the partial data when a decompression error happens while extracting a file, has been added. It requires lzlib 1.11-rc2 or newer in order to recover as much data as possible from each damaged member.

* The new option '--no-solid' has been added. It allows tarlz revert to default behavior if, for example, tarlz is invoked through an alias like tar='tarlz --solid'.

* '-c, --create' and '-r, --append' now minimize the dictionary size of the lzip members created.

* Tarlz now detects when the archive being created or enlarged is among the files to be dumped, appended or concatenated, and skips it.

  * The option '-V, --version' now shows the version of lzlib being used.


Please send bug reports and suggestions to address@hidden


Regards,
Antonio Diaz, tarlz author and maintainer.
Software and Catalan political prisoners just want to be free.
--
If you are distributing software in xz format, please consider using lzip instead. See http://www.nongnu.org/lzip/lzip_benchmark.html#xz1 and http://www.nongnu.org/lzip/xz_inadequate.html




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