Pdlzip

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Introduction

Pdlzip is a permissively licensed implementation of the lzip data compressor, intended for those who can't distribute (or even use) GPL licensed Free Software. (The name of pdlzip comes from 'public domain lzip'). Pdlzip is written in C and is compatible with lzip 1.4 or newer.

Lzip is a lossless data compressor with a user interface similar to the one of gzip or bzip2. Lzip uses a simplified form of the 'Lempel-Ziv-Markov chain-Algorithm' (LZMA) stream format to maximize interoperability. The maximum dictionary size is 512 MiB so that any lzip file can be decompressed on 32-bit machines. Lzip provides accurate and robust 3-factor integrity checking. Lzip can compress about as fast as gzip (lzip -0) or compress most files more than bzip2 (lzip -9). Decompression speed is intermediate between gzip and bzip2. Lzip is better than gzip and bzip2 from a data recovery perspective. Lzip has been designed, written, and tested with great care to replace gzip and bzip2 as the standard general-purpose compressed format for Unix-like systems.

Pdlzip is also able to decompress legacy lzma-alone (.lzma) files. Lzma-alone is a very bad format; it is essentially a raw LZMA stream. If you keep any lzma-alone files, it is advisable to recompress them to lzip format. Lziprecover can convert some lzma-alone files to lzip format without recompressing.

Pdlzip includes public domain (de)compression code from the LZMA SDK (Software Development Kit) written by Igor Pavlov.

Documentation

Pdlzip only includes a man page and a README file. For information about the lzip file format see the online manual of lzip below.

The manual is available in the info system of the GNU Operating System. Use info to access the top level info page. Use info lzip to access the lzip section directly.

An online manual for lzip can be found at manual/lzip_manual.html.

Download

The latest released version of pdlzip can be found at http://download.savannah.gnu.org/releases/lzip/pdlzip/. You may also subscribe to lzip-bug and receive an email every time a new version is released.

You may compile and optionally install pdlzip by running the following commands:

tar -xf pdlzip[version].tar.gz
cd pdlzip[version] && ./configure && make check

then (as root) type:

make install

Once pdlzip is installed, the files from archive "foo.tar.lz" can be extracted using the command "pdlzip -cd foo.tar.lz | tar -xf -".

How to get help

For general discussion of bugs in pdlzip the mailing list lzip-bug@nongnu.org is the most appropriate forum. Please send messages as plain text. Please do not send messages encoded as HTML nor encoded as base64 MIME nor included as multiple formats. Please include a descriptive subject line. If all of the subject are "bug in pdlzip" it is impossible to differentiate them.

An archive of the bug report mailing list is available at http://lists.gnu.org/mailman/listinfo/lzip-bug.

How to help

To contact the author, either to report a bug or to contribute fixes or improvements, send mail to lzip-bug@nongnu.org. Please send messages as plain text. If posting patches they should be in unified diff format against the latest version. They should include a text description.

See also the lzip project page at Savannah.

Licensing

Pdlzip is free software. The (de)compression code is in the public domain. The rest is under a 2-clause BSD license.

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Copyright © 2023 Antonio Diaz Diaz
Lzip logo Copyright © 2013 Sonia Diaz Pacheco

You are free to copy, modify, and distribute all or part of this article without limitation.

Updated: 2023-12-28

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