Lunzip

Introduction

Lunzip is a decompressor for lzip files. It is written in C and its small size makes it well suited for embedded devices or software installers that need to decompress files but do not need compression capabilities.

Lunzip uses the same well-defined exit status values used by lzip and bzip2, which makes it safer when used in pipes or scripts than decompressors returning ambiguous warning values, like gunzip.

The 4 factor integrity checking of the lzip format guarantees that the decompressed version of the data is identical to the original. This guards against corruption of the compressed data, and against undetected bugs in lunzip (hopefully very unlikely). The chances of data corruption going undetected are microscopic. Be aware, though, that the check occurs upon decompression, so it can only tell you that something is wrong. It can't help you recover the original uncompressed data.

If you ever need to recover data from a damaged lzip file, try the lziprecover program.

Lunzip replaces every file given in the command line with a decompressed version of itself. Each decompressed file has the same modification date, permissions, and, when possible, ownership as the corresponding compressed file. Lunzip is able to read from some types of non regular files if the "--stdout" option is specified.

If no file names are specified, lunzip decompresses from standard input to standard output. In this case, lunzip will decline to read compressed input from a terminal.

Lunzip will correctly decompress a file which is the concatenation of two or more compressed files. The result is the concatenation of the corresponding uncompressed files. Integrity testing of concatenated compressed files is also supported.

The amount of memory required by lunzip to decompress a file is only a few tens of KiB larger than the dictionary size used to compress that file.

Learn more about lzip in the Lzip Home Page.

Documentation

Lunzip 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 here.

Download

The latest released version of lunzip can be found here. You may also subscribe to Freecode and receive an email every time a new version is released.

How to Get Help

For general discussion of bugs in lunzip 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 lunzip" it is impossible to differentiate them.

An archive of the bug report mailing list is available at http://lists.nongnu.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

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

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

Updated: 2013/05/23