A catch-all text and data compression and decompression software for Windows. 7-zip is both a high-compression alternative to ZIP and a near-equal alternative to RAR. It is an open-source, Free Software program that offers a great range of compression options and no licensing issues. Allows the creation of ZIP and the new 7z file format. The program is currently only available for Windows, integrates with the Windows Shell, self-extracting file creation, and available for 40 languages.
A *NIX port called p7zip now exists. This is a port of the CLI version only. Although the best compression method to date for many types of files, large text files or groups of similar text files continue to compress better with RAR. However, it is far less restrictive than RAR's licensing issues which can mean fewer headaches for big institutions.
Considered a must-have for decompressing a wide variety of formats (at this writing - has probably increased): ZIP, CAB, RAR, ARJ, GZIP, BZIP2, TAR, CPIO, RPM and DEB. Negatively, the program lacks a clean, drag-and-drop interface.