7-Zip – a free file archiver that uses many compressed file formats

7-Zip is a free open source software that can be used to compress or uncompress files in many commonly used file formats. The default compressed file format is 7z but other common formats such as ZIP, TAR, etc. can be used.   7-Zip download files are currently available for Windows and Linux.  This FAQ lists more information on how to use 7-Zip.