The tar (Tape ARchiver) command is one of the oldest commands in UNIX systems and is designed to work with tape drives. The command combines files into a single file to be written to magnetic tape. Although the tar command was created to work with tape devices, nowadays it is more often necessary to work with files located on disks; if you use -f option, the archive is stored into specified file. By itself, tar is an archiver with very limited capabilities, e.g., it cannot compress files on its own. The Gnu version of the tar command on Linux systems can invoke the gzip, bzip2, or any other archivers to create compressed archives. The use of external archivers is reflected in the names of the archives, which usually have the extensions.tar.gz (.tgz) or .tar.bz2 (.tbz2), depending on which archive was used to compress the files.