Editing Gzip (section)

==Implementations==
{{Infobox software
| name                 = NetBSD Gzip / FreeBSD Gzip
| developer            = The NetBSD Foundation
| genre                = [[Data compression]]
| programming language = [[C (programming language)|C]]
| license              = [[BSD licenses|Simplified BSD License]]
| website              = hide <!-- Don't display the GNU Gzip URL from Wikidata on the BSD Gzip infobox -->
| repo                 = {{URL|//cvsweb.netbsd.org/bsdweb.cgi/src/usr.bin/gzip/}}
}}
Various implementations of the program have been written. The most commonly known is the GNU Project's implementation using [[LZ77|Lempel-Ziv]] coding (LZ77). [[OpenBSD]]'s version of gzip is actually the [[compress]] program, to which support for the gzip format was added in OpenBSD 3.4. The "g" in this specific version stands for ''[[wikt:gratis|gratis]]''.<ref>{{cite web|url=https://man.openbsd.org/gzip.1#HISTORY|title=OpenBSD gzip(1) manual page|website=Openbsd.org|access-date=2018-02-04|publisher=OpenBSD}}</ref> [[FreeBSD]], [[DragonFly BSD]] and [[NetBSD]] use a BSD-licensed implementation instead of the GNU version; it is actually a [[command-line interface]] for [[zlib]] intended to be compatible with the GNU implementations' options.<ref>{{cite web|url=http://man.freebsd.org/gzip|title=gzip|publisher=Man.freebsd.org|date=2011-10-09|access-date=2014-03-01|archive-date=17 December 2019|archive-url=https://web.archive.org/web/20191217104949/https://www.freebsd.org/cgi/man.cgi?gzip|url-status=live}}</ref> These implementations originally come from [[NetBSD]], and support decompression of [[bzip2]] and the Unix [[pack (compression)|pack]] format.

An alternative compression program achieving 3-8% better compression is [[Zopfli]]. It achieves gzip-compatible compression using more exhaustive algorithms, at the expense of compression time required.  It does not affect decompression time.

<code>pigz</code>, written by Mark Adler, is compatible with gzip and speeds up compression by using all available CPU cores and threads.<ref>{{cite web|url=https://zlib.net/pigz/|author=Mark Adler|website=zlib.net|title=pigz: A parallel implementation of gzip for modern multi-processor, multi-core machines|date=2017|access-date=23 December 2018|archive-date=18 December 2018|archive-url=https://web.archive.org/web/20181218151754/http://zlib.net/pigz/|url-status=live}}</ref>

=== Damage recovery ===
Data in blocks prior to the first damaged part of the archive is usually fully readable. Data from blocks not demolished by damage that are located afterward ''may'' be [[Data recovery|recoverable]] through difficult workarounds.<ref>[https://web.archive.org/web/20180708075208/http://www.gzip.org/recover.txt Recovering a damaged .gz file – Jean-loup Gailly, GZip.org]</ref>