XZ Utils
| Developer(s) | The Tukaani Project |
|---|---|
| Stable release | 5.0.3 / May 21, 2011 |
| Preview release | 5.1.1 / April 12, 2011 |
| Written in | C |
| Operating system | Cross-platform |
| Type | Data compression |
| License | Bulk system under GNU LGPL v2.1 and public domain; Build system under GNU GPL v2, GNU GPL v3, and public domain; source code in public domain |
| Website | tukaani.org/xz/ |
XZ Utils (previously LZMA Utils) is a set of free command-line lossless data compressors, including LZMA and xz, for Unix-like operating systems and (as of version 5.0) Microsoft Windows.
XZ Utils consists of three major components:
- xz and lzma, the command-line compressor; analogous to gzip
- xzdec and lzmadec, the command-line decompressor; analogous to zcat
- liblzma, a software library with an API similar to zlib
XZ Utils can compress and decompress both the xz and lzma file formats, but since the LZMA format is now legacy[1], XZ Utils compresses by default to xz.
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[edit] Implementation
Both the behavior of the software as well as the properties of the file format have been designed to work analogously to those of the popular Unix compressing tools gzip and bzip2. It consists of a Unix port of Igor Pavlov's LZMA-SDK that has been adapted to fit seamlessly into Unix environments and their usual structure and behavior.
Just like gzip and bzip, xz and lzma can only compress single files (or data streams) as input; they cannot bundle multiple files into a single archive; to do this an archiving program is used first, such as tar.
Compressing an archive:
xz my_archive.tar # results in my_archive.tar.xz lzma my_archive.tar # results in my_archive.tar.lzma
Decompressing the archive:
unxz my_archive.tar.xz # results in my_archive.tar unlzma my_archive.tar.lzma # results in my_archive.tar
Version 1.22 or greater of the GNU implementation of tar has transparent support for lzma- or xz-compressed tarballs, using the switches --xz or -J for xz compression, and --lzma for LZMA compression.
Creating an archive and compressing it:
tar -c --xz -f my_archive.tar.xz /some_directory # results in my_archive.tar.xz tar -c --lzma -f my_archive.tar.lzma /some_directory # results in my_archive.tar.lzma
Decompressing the archive and extracting its contents:
tar -x --xz -f my_archive.tar.xz # results in /some_directory tar -x --lzma -f my_archive.tar.lzma # results in /some_directory
[edit] Development and adoption
XZ Utils is being developed as part of The Tukaani Project (headed by Mike Kezner), a small group of developers who once had maintained a Linux distribution based on Slackware. Most of the source code for XZ Utils has been released into the public domain with the rest being subject to different free software licenses.
A number of Linux distributions, including Slackware and Arch linux[2], use xz for compressing their software packages. It is also used by the GNU FTP archive.
Binaries are available for GNU/Linux, Microsoft Windows, and FreeDOS.
[edit] See also
[edit] External links
[edit] References
- ^ LZMA Utils, http://tukaani.org/lzma/, retrieved 2011-01-25
- ^ Pierre Schmitz (2010-03-23). "News: Switching to xz compression for new packages". http://www.archlinux.org/news/switching-to-xz-compression-for-new-packages/.
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