OStatic

In computing, Tar (derived from Tape ARchive) is both a file format (in the form of a type of archive bitstream) and the name of the program used to handle such files. The format was standardized by POSIX.1-1988 and later POSIX.1-2001. Initially developed as a raw format, used for tape backup and other sequential access devices for backup purposes, it is now commonly used to collate collections of files into one larger file, for distribution or archiving, while preserving file system information such as user and group permissions, dates, and directory structures.Tar's linear roots can still be seen in its ability to work on any data stream and its slow partial extraction performance, as it has to read through the whole archive to extract only the final file. A Tar file (somefile.tar), when subsequently compressed using a compression utility such as gzip, bzip2, or (formerly) compress, produces a compressed Tar file with a filename extension indicating the type of compression (e.g.: somefile.tar.gz). A .tar file is commonly referred to as a Tarball, which is usually compressed to save disk space.As is common with Unix utilities, Tar is a single specialist program. It follows the Unix philosophy in that it can do only one thing (archive), but do it well. Tar is most commonly used in tandem with an external compression utility, since it has no built-in data compression facilities. These compression utilities generally only compress a single file, hence the pairing with Tar, which can produce a single file from many files. To ease this common usage, the BSD and GNU versions of Tar support the command line options -z (gzip), and -j (bzip2) which will compress or decompress the archive file it is currently working with, although even in this case the (de)compression is still actually performed by an external program.    [edit]