Just a side note: tar is not really a compression utility and is not aimed at compressing data. The tar utility is for building an archive of several files (i.e. storing several files into a single file, with some way of extracting them afterwards), originally on a tape, today into a single file.. Now, having said that, there are often some options of tar that implicitly call the zip, gzip or compress utilities after having built the archive to reduce the size of the archive.