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init
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<p>In <a href="/facts/Unix/0pNL2seI">Unix</a>-based computer <a href="/facts/Operating_system/8XTuvMh2">operating systems</a>, init (short for <i>initialization</i>) is the first <a href="/facts/Process_(computer_science)/Vcq7EnUV">process</a> started during <a href="/facts/Booting/j6N1kRpc">booting</a> of the operating system. Init is a <a href="/facts/Daemon_(computing)/bzuEVGGX">daemon</a> process that continues running until the system is shut down. It is the direct or indirect <a href="/facts/Parent_process/SGkeTvEu">ancestor</a> of all other processes and automatically adopts all <a href="/facts/Orphan_process/7fodYdF5">orphaned processes</a>. Init is started by the <a href="/facts/Kernel_(operating_system)/uEj4U3Rz">kernel</a> during the <a href="/facts/Booting/j6N1kRpc">booting</a> process; a <a href="/facts/Kernel_panic/aSp4ojw2">kernel panic</a> will occur if the kernel is unable to start it, or it should die for any reason. Init is typically assigned <a href="/facts/Process_identifier/q9TlqHEP">process identifier</a> 1. </p><p>In Unix systems such as <a href="/facts/UNIX_System_III/nkoNsbM6">System III</a> and <a href="/facts/UNIX_System_V/Epm6GEY4">System V</a>, the design of init has diverged from the functionality provided by the init in <a href="/facts/Research_Unix/5oWmUdwo">Research Unix</a> and its <a href="/facts/Berkeley_Software_Distribution/XQKcURrh">BSD</a> derivatives. Up until the early 2010s, most <a href="/facts/Linux_distribution/0vVl4N4f">Linux distributions</a> employed a traditional init that was somewhat compatible with System V, while some distributions such as <a href="/facts/Slackware_Linux/eGJIIHgW">Slackware</a> use BSD-style startup scripts, and other distributions such as <a href="/facts/Gentoo_Linux/zX81Cqs8">Gentoo</a> have their own customized versions. </p><p>Since then, several additional init implementations have been created, attempting to address design limitations in the traditional versions. These include <a href="/facts/Launchd/baJP73zv">launchd</a>, the <a href="/facts/Service_Management_Facility/P6NpgQrN">Service Management Facility</a>, <a href="/facts/Systemd/zls5HoVh">systemd</a>, <a href="/facts/Runit/DYb7YdTM">Runit</a> and <a href="/facts/OpenRC/fPka0TGp">OpenRC</a>. </p>