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[Lzip-bug] Tarlz 0.15 released
Antonio Diaz Diaz
[Lzip-bug] Tarlz 0.15 released
Sat, 13 Apr 2019 17:40:34 +0200
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I am pleased to announce the release of tarlz 0.15.
Tarlz is a massively parallel (multi-threaded) combined implementation
of the tar archiver and the lzip compressor. Tarlz creates archives in a
simplified posix pax format compressed with lzip, keeping the alignment
between tar members and lzip members. This method adds an indexed lzip
layer on top of the tar archive, making it possible to decode the
archive safely in parallel. The resulting multimember tar.lz archive is
fully backward compatible with standard tar tools like GNU tar, which
treat it like any other tar.lz archive. Tarlz can append files to the
end of such compressed archives.
Tarlz can create tar archives with five levels of compression
granularity; per file, per block (default), per directory, appendable
solid, and solid. It can also create uncompressed tar archives.
Of course, compressing each file (or each directory) individually can't
achieve a compression ratio as high as compressing solidly the whole tar
archive, but it has the following advantages:
* The resulting multimember tar.lz archive can be decompressed in
parallel, multiplying the decompression speed.
* New members can be appended to the archive (by removing the EOF
member), and unwanted members can be deleted from the archive.
Just like 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
The sources can be downloaded from
The sha256sum is:
Changes in version 0.15:
* The new option '--delete', which deletes files and directories from
an archive in place, has been added. It currently can delete only from
uncompressed archives and from archives with individually compressed
files ('--no-solid' archives).
* Multi-threaded listing of compressed archives with format
violations (for example, an extended header without the corresponding
ustar header) has been fixed.
Please send bug reports and suggestions to address@hidden
Antonio Diaz, tarlz author and maintainer.
Self-determination is a right, not a crime. Free Catalan political
If you care about long-term archiving, please help me replace xz with
lzip. See http://www.nongnu.org/lzip/lzip_benchmark.html#xz1
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