Editing Cron (section)

=== Nonstandard predefined scheduling definitions === 
Some cron implementations<ref name="freebsd">{{cite web|url=https://www.freebsd.org/cgi/man.cgi?crontab%285%29 | title= FreeBSD File Formats Manual for CRONTAB(5) |publisher=The FreeBSD Project }}</ref> support the following non-standard macros:

{| class="wikitable"
|-
!Entry
!Description
!Equivalent to
|-
|<code>@yearly</code> (or <code>@annually</code>)
|Run once a year at midnight of 1 January
|<code>0 0 1 1 *</code>
|-
|<code>@monthly</code>
|Run once a month at midnight of the first day of the month
|<code>0 0 1 * *</code>
|-
|<code>@weekly</code>
|Run once a week at midnight on Sunday
|<code>0 0 * * 0</code>
|-
|<code>@daily</code> (or <code>@midnight</code>)
|Run once a day at midnight
|<code>0 0 * * *</code>
|-
|<code>@hourly</code>
|Run once an hour at the beginning of the hour
|<code>0 * * * *</code>
|-
|<code>@reboot</code>
|Run at startup
|{{N/A}}
|}

<code>@reboot</code> configures a job to run once when the daemon is started. Since cron is typically never restarted, this typically corresponds to the machine being booted. This behavior is enforced in some variations of cron, such as that provided in [[Debian]],<ref name="debiancron">{{cite web|url=http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=77563#30 |title=#77563 - cron: crontab(5) lies, '@reboot' is whenever cron restarts, not the system |website=Debian bug tracking system |access-date=2013-11-06}}</ref> so that simply restarting the daemon does not re-run <code>@reboot</code> jobs.

<code>@reboot</code> can be useful if there is a need to start up a server or daemon under a particular user, and the user does not have access to configure [[init]] to start the program.