Editing Init (section)

{{Short description|UNIX system component}}
{{About|the Unix process||INIT (disambiguation)}}
{{Primary sources|date=December 2020}}
{{Lowercase title}}
[[File:Version 7 UNIX SIMH PDP11 Etc.png|thumb|[[Version 7 Unix]]: {{mono|/etc}} listing, showing {{mono|init}} and {{mono|rc}}]]
[[File:Version 7 UNIX SIMH PDP11 Etc Rc.png|thumb|Version 7 Unix: contents of an {{mono|/etc/rc}} [[Bourne shell]] script]]

In [[Unix]]-based computer [[operating system]]s, '''init''' (short for ''initialization'') is the first [[process (computer science)|process]] started during [[booting]] of the operating system. Init is a [[daemon (computing)|daemon]] process that continues running until the system is shut down. It is the direct or indirect [[parent process|ancestor]] of all other processes and automatically adopts all [[orphan process|orphaned processes]]. Init is started by the [[kernel (operating system)|kernel]] during the [[booting]] process; a [[kernel panic]] will occur if the kernel is unable to start it, or it should die for any reason. Init is typically assigned [[process identifier]] 1.

In Unix systems such as [[UNIX System III|System III]] and [[UNIX System V|System V]], the design of init has diverged from the functionality provided by the init in [[Research Unix]] and its [[Berkeley Software Distribution|BSD]] derivatives. Up until the early 2010s,<ref>{{Cite web |date=2018-11-08 |title=Lennart Poettering on systemd's Tumultuous Ascendancy |website=The New Stack |url=https://thenewstack.io/unix-greatest-inspiration-behind-systemd/ |access-date=2024-01-30 |archive-url=https://web.archive.org/web/20181108025744/https://thenewstack.io/unix-greatest-inspiration-behind-systemd/ |archive-date=2018-11-08 |url-status=live}}</ref>{{failed verification|date=February 2024}} most [[Linux distribution]]s employed a traditional init that was somewhat compatible with System&nbsp;V, while some distributions such as [[Slackware Linux|Slackware]] use BSD-style startup scripts, and other distributions such as [[Gentoo Linux|Gentoo]] have their own customized versions.

Since then, several additional init implementations have been created, attempting to address design limitations in the traditional versions. These include [[launchd]], the [[Service Management Facility]], [[systemd]], [[Runit]] and [[OpenRC]].