gzip is a compression program, which, along with the appropriate file format gzip is available virtually in all computer OS. gzip is short name of GNU Zip. Zip came from the word Zipper. OpenBSD has a BSD-license and free reimplementation is done with gzip, which is compatible with the GNU tools.
The Technology of gzip
gzip provides a good degree of compression and is free. gzip is based on the deflate algorithm, a combination of algorithm. The usual file extension for gzip compressed files today are .gz . Since gzip only compresses a single file, multiple files are collections of tar are usually first combined into a so-called tarballs, before it is compressed with gzip. Such collections will usually carry the double extension .tar.gz or even simply .tgz . This method allows for better overall compression, since so redundancies between the individual files can be exploited ( progressive compression ), but difficult to access the individual components.
Usage of gzip
Previously we wrote how to speed up WordPress by gzip compression from .htaccess. Content-Encoding/Accept-Encoding and Transfer-Encoding headers in HTTP allow clients to optionally receive compressed HTTP responses. gzip utility on UNIX systems has some alternative names like gunzip, zcat etc. gnuwin32 is for Windows OS. Browsers normally deflate the received components served as gzipped.
We use gzip today mainly for optimizing web page speed, like in the CMS WordPress. The funny fact is, sometimes due to wrong configuration of the WordPress plugins or .htaccess, the whole page, instead of becoming of a human readable format when opened on a browser, starts to get downloaded to the user. That is the reason, WordPress Administrators must check the webpages manually from various browsers.