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See also: File Formats | Compression | Gzip

File extension: .tar

Compressed TAR: .tar.gz (see Gzip)

A typically curt UNIX abbreviation for Tape ARchive, tar is a tool that was originally used to back up numerous files onto one continuous strip of tape. tar can also be used to string numerous files together into one large file, which is how it is most frequently used today.

Tar files may have any extension, but it has become standard to use ".tar" and treat it as a file format in and of itself. tar is not a form of compression but is often used in combination with the compression program gzip. Files in this format then have the ".tar.gz" extension. Older UNIX compressed archives may have a "tar.Z" extension, indicating that the older "compress" tool was used in place of gzip.

The seperation of archival and compression systems point to a typical UNIX design philosophy - giving users full control over how their data is handled, or "a program should do one thing well". Unfortunately because the source files are first archived, then compressed, the entire archive must be decompressed before extracting a single file, which can be very time-consuming. On the positive side, file sizes are often smaller than with combined compression/archival tools like ARJ that compress each file individually, because the compression sample size is much larger.