7-Zip is a file archiver program that claims to compress files into smaller size compared to other programs such as WinRAR and WinZip. The program can pack and unpack various formats such as ZIP, GZIP, BZIP2, TAR, and of course, its own format, 7z. The 7z format itself is actually a container that supports few compression method such as LZMA, Deflate and BZIP2, and it defaults to LZMA.

The program is usually packaged in Linux as p7zip, and is installable in Ubuntu using apt-get as the following;

$ sudo apt-get install p7zip

Though there are many options available, extracting or unpacking a 7z archive is as easy as the following command;

$ 7z x archive.7z