gzip

Gzip is a compression program, as well as the appropriate file format gzip, is practically available for all computer operating systems ( under the terms of the GPL in the source code ).

General gzip is short for " GNU zip ", where " zip" was borrowed from the English word for the zipper. OpenBSD has made a BSD - licensed reimplementation called free zip, but which is completely compatible with the GNU tools.

Gzip provides a good degree of compression and is free from patented algorithms. It was originally developed by Jean -Loup Gailly to replace Unix compress the old program. Mark Adler wrote the decompression software gunzip.

Technology

Gzip is based on the Deflate algorithm, which is a combination of LZ77 and Huffman coding. Deflate was developed in response to the patents were LZW compression or other algorithms. Also the zip file format used mainly for Deflate compression, but should not be confused with gzip otherwise.

To simplify the development of software that uses data compression, the zlib library was written. It supports the gzip file format and Deflate compression. The library is widely used because it is small, efficient and versatile.

Example Views

Grab a file:

Gzip A packed file unzip:

Gzip-d or

Gunzip Issue a compressed text file:

Zcat A blown save compressed file to the error location / unpack:

Zcat > gzip - compressed files

Template: Infobox file format / Maintenance / MagischeZahlHex missing \ x1F \ X8b \ x08 ( ASCII C notation )

The usual file extension for gzip compressed files is today. Gz, earlier also. , For Since gzip compressed single files only, set of files are usually first with tar combined into a so-called tarball before they are compressed using gzip. Such collections bear then usually double the ending. Tar.gz or simply. Tgz. This method allows for overall better compression because such redundancies between the individual files can be exploited (progressive compression), but difficult to access the individual components.

Dissemination

On Unix, the compression is gzip standard today, because it allows a good compromise between high speed and good data reduction for many tasks. Where is less important than speed to minimum file sizes ( for example in the wide distribution of data over relatively slow networks), but are increasingly bzip2 and LZMA used ( as with gzip in combination with tar).

The zlib - compressed file format, the Deflate algorithm and the gzip file format were standardized in 1996 as a Request for Comments RFC 1950, RFC 1951 and RFC 1952.