XZ Utils

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XZ Utils
Basic data

developer Tukaani Project ( Slackware )
Current  version 5.2.4
( April 29, 2018 )
operating system Unix-like ( BSD , Linux , Solaris )
programming language C.
category Data compression program
License mostly in the public domain
https://tukaani.org/xz/

The XZ Utils (formerly LZMA Utils ) are a collection of free packing programs for Unixoid systems that was created as part of the Tukaani Project of the Linux distribution Slackware .

The data compression algorithm is based on an adapted porting of the LZMA code of the LZMA SDK by Igor Pavlov to Linux and other Unix-like platforms.

The XZ Utils offer the usual handling of packed files from the established Linux packing programs gzip and bzip2 for the advanced Lempel-Ziv-Markow data compression algorithm (LZMA) as well as a basis for its easy integration into other programs. In addition, they have a very similar operation, they also do not archive several files themselves, but instead rely on the combination with pure archive formats such as tar and also introduce a new file format with comparable properties ( xz , see below).

Most of the source code is in the public domain , otherwise under various free software licenses .

The compression is more efficient, but usually considerably slower than the compression with gzip, bzip2 or rar , but leads to 30% or 15% smaller results than with gzip or bzip2. With LZMA-based compression, sufficient working memory results in largely independent, constant decompression times that are largely independent of the compression settings, which are usually well below the varying times of bzip2, but remain significantly behind compared to gzip.

The XZ Utils consist of several individual tools for handling xz files:

xz
is a command line program that works in the same way as gzip or bzip2 and has a modeled operating concept
liblzma
is a program library with a programming interface , attached to the extending zlib inspired
xzdec
- a pure decompression tool

There is also a collection of shell - scripts to facilitate the handling of xz files.
This are the commands xz, unxz, xzcatand xzgrep(or for backward compatibility with the older LZMA Utils also lzma, unlzma, lzcatand lzgrep) are available.

Data format

The XZ Utils (like the LZMA Utils ) can not handle the 7z data format of the LZMA reference implementation (s) (7-Zip, LZMA SDK). They generate files in their own xz format, which works in the same way as the gz and bz2 formats. Conversely, 7-Zip and the LZMA SDK have also been able to open xz files since the 9th version.

history

The project began under the name LZMA Utils as a Unix port of the LZMA code from the LZMA-SDK, which only generated raw LZMA streams without any header data . The XZ Utils can emulate the behavior of the command line programs of the LZMA Utils and open its files. The name was changed on December 31, 2008 with version 4.999.7beta. The file format (xz) has not been changed since then. Since it also has a suitable container format with xz , it is the second complete solution after lzip for using LZMA in Unix style and has meanwhile become more widespread than this.

When the LZMA SDK (from which the XZ Utils are derived) became public domain with version 4.61 beta on November 23, 2008, the license of the XZ Utils was changed accordingly.

Platforms

The XZ Utils are available for various Linux distributions. As a binary package, they are available as a .deb package and a .rpm package. This allows the software to be installed on most Linux distributions without any problems. Packages are available for Debian , Ubuntu , Gentoo , Mandriva , openSUSE and Red Hat , for example .

Binary packages also exist for BSD operating systems. Alternatively, users of BSD operating systems such as OpenBSD , NetBSD , FreeBSD , DragonFly BSD can also install the software through the port system.

From version 4.999.8beta there is also experimental support for Windows .

See also

  • lzip is a similar project
  • p7zip is the direct porting of the command line tools from 7-Zip to Unix-like operating systems

Web links

Individual evidence

  1. ↑ XZ Utils Release Notes . (accessed April 17, 2019).
  2. ↑ http://tukaani.org/lzma/benchmarks.html