7-Zip
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7-Zip is an open source file archiver predominantly for the Microsoft Windows operating system. It operates either as a command line program or with a graphical user interface. It also features integration with the Windows shell environment. 7-Zip is free software, distributed under the GNU LGPL license. Several attempts over the last 2 years have been made to port this onto Linux and one such example is p7zip (http://p7zip.sourceforge.net/). The spring 2005 release of KDE will officially be the first Unix desktop environment to support 7-Zip. It is a competitor to the market-leading WinZip and WinRAR programs, both of which are closed source.
The latest version is 4.20, released on May 30th, 2005.
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Supported formats
7-Zip introduced the flexible 7z file format, but it also supports a number of other compressed and uncompressed archive file formats, including zip, Microsoft cabinet (cab) files, rar, arj, gzip, bzip2, tar, cpio, rpm, and Debian deb archives. Due to legal issues, the ace format is not supported anymore. 7-Zip is also able to create self-extracting archive files when used with the 7z format.
7-Zip compression algorithms
By default, the program creates files in the 7z archive format (with the file extension .7z) using the LZMA algorithm for compression. These defaults allow the program to achieve the highest compression ratio compared to other popular high compression formats such as ACE and RAR which are based on older, proprietary algorithms. Such files have the MIME-type application/x-7z-compressed.
For ZIP and gzip files, 7-Zip uses a modified implementation of the DEFLATE algorithm that is tuned for higher compression levels at the expense of speed. This implementation is also used in the AdvanceCOMP tools.
Supported features
7-Zip supports many features that are found in other compression software.
Encryption
For 7z format files, 7-Zip also supports 256-bit AES encryption of both files and the 7z directory structure, preventing users without the password from even seeing the archive contents. The native 7z file format is an open, modular architecture which allows it to contain files compressed using different algorithms. Filenames are stored as unicode.
Volumes
7-Zip supports volumes of varying sizes which is useful for backups on to removable media such as writable CDs and DVDs.
See also
External links
- 7-Zip Official Website (http://www.7-zip.org/)
- Project: 7-Zip (http://sourceforge.net/projects/sevenzip/) - 7-Zip's SourceForge project page.
- A quick port of 7z.exe and 7za.exe (command line version of 7zip) for Unix (http://p7zip.sourceforge.net/)
- Resolved KDE 7-Zip issues (http://bugs.kde.org/show_bug.cgi?id=48267) - Reasons for not including support within the KDE ARK package.de:7-Zip