Editing Cron (section)

=== Modern versions ===
With the advent of the [[GNU Project]] and [[Linux]], new crons appeared. The most prevalent of these is the Vixie cron, originally coded by [[Paul Vixie]] in 1987. Version 3 of '''Vixie cron''' was released in late 1993. Version 4.1 was renamed to '''[[Internet Systems Consortium|ISC]] Cron''' and was released in January 2004. Version 3, with some minor bugfixes, is used in most distributions of Linux and BSDs.

In 2007, [[Red Hat]] forked vixie-cron 4.1 to the [[cronie]] project, adding features such as PAM and SELinux support.<ref>{{cite web |title=cronie-crond/cronie |url=https://github.com/cronie-crond/cronie?tab=readme-ov-file |publisher=cronie-crond |date=20 September 2024}}</ref> In 2009, [[anacron]] 2.3 was merged into cronie.<ref>{{cite web |title=Initial upload of anacron-2.3 which should be optimized for better · cronie-crond/cronie@55f4057 |url=https://github.com/cronie-crond/cronie/commit/55f40574a94185a73df8043c4f71f016703c1009 |website=GitHub |language=en}}</ref> Anacron is not an independent cron program however; another cron job must call it. 

[[DragonFly BSD|DragonFly]]'s dcron was made by its founder [[Matthew Dillon (computer scientist)|Matt Dillon]], and its maintainership was taken over by Jim Pryor in 2010.<ref>{{cite mailing list|url=https://mailman.archlinux.org/pipermail/arch-general/2010-January/009981.html |mailing-list=arch-general@archlinux.org |title=Cron  |date=2010-01-05 |access-date=2013-11-06 |first=Jim |last=Pryor}}</ref>

In 2003, Dale Mellor introduced mcron,<ref>{{cite web|url=https://www.gnu.org/software/mcron/design.html |title=Mcron - User Requirements and Analysis |first=Dale |last=Mellor |date=2003-06-01 |access-date=2019-06-11}}</ref> a cron variant written in [[GNU Guile#Guile Scheme|Guile]] which provides cross-compatibility with Vixie cron while also providing greater flexibility as it allows arbitrary [[Scheme (programming language)|scheme]] code to be used in scheduling calculations and job definitions. Since both the mcron daemon and the crontab files are usually written in scheme (though mcron also accepts traditional Vixie crontabs), the cumulative [[State (computer science)|state]] of a user's job queue is available to their job code, which may be scheduled to run [[iff]] the results of other jobs meet certain criteria. Mcron is deployed by default under the [[Guix]] package manager, which includes provisions ([[GNU_Guix#Init_system|services]]) for the package manager to [[Monad_(functional_programming)|monadically]] emit mcron crontabs while both ensuring that packages needed for job execution are installed and that the corresponding crontabs correctly refer to them.<ref>{{cite web|url=https://www.gnu.org/software/guix/manual/en/html_node/Scheduled-Job-Execution.html#Scheduled-Job-Execution |title=GNU Guix Reference Manual: 8.8.2 Scheduled Job Execution |publisher=GNU Guix |date=2019-05-19 |access-date=2019-06-11}}</ref>

A [[webcron|webcron solution]] schedules ring tasks to run on a regular basis wherever cron implementations are not available in a [[web hosting service|web hosting]] environment.