TAR file format
In computing, tar is a type of packing file format: the Tape ARchive format. It is used widely in the Unix-like world (including Linux) and more recently in Microsoft Windows. tar does not support compression, but is used to accumulate a large collection of files into a single archive file (packer), while preserving filesystem information such as user/group, permissions, date, and directory structure.tar was originally developed for use with linear-access devices such as tape drives. Somewhere along the line the -f argument was added and tar is now more frequently used as a general archive utility. tar's linear roots can be seen in its slow partial-extraction performance (whereby it has to be read through the whole archive to extract only the final file).
tar is most commonly used in tandem with an external compression format such as gzip, bzip2 or, formerly, compress. These are compression utilities and generally only compress a single file, hence the pairing with tar
- A tar file (tarball) that is subsequently compressed using gzip usually has an extention of .tar.gz (.tar being the tar file, .gz being added by gzip). Due to the limitations on file extensionss on DOS, these are also sometimes called TGZ files.
- A tar file that is subsequently compressed using bzip2 has an extension of .tar.bz2 or, sometimes, a .TBZ
