#pragma section-numbers off

This page describes the basic use of cron on HCoop systems.

[[TableOfContents]]

= Prerequisites =

It is very important that you read the [:MemberManual/RunningUnattendedCommands:Running Unattended Commands page] to understand the general idea of how to run unattended commands on Mire.

= Requesting cron permissions =

Use [https://members2.hcoop.net/portal/sec the security settings page] of the portal to request permission to use cron.  You won't be able to create a crontab before submitting a request and having it approved.

= Making a cron configuration file =

Cron needs a special configuration file to tell it how to operate.  It is suggested that this file be called {{{~/.crontab}}}, though it can have any name.

For an explanation of the format of this file, run:

{{{
man 5 crontab
}}}

= Activating your cron configuration =

Once you are satisfied with your setup, run the following command to activate your changes, assuming that your configuration file is called {{{~/.crontab}}}:

{{{
crontab ~/.crontab
}}}

= Examples =

One convention for making scripts to run commands in their own PAG, as specified by the [:MemberManual/RunningUnattendedCommands:Running Unattended Commands page], is to create the {{{~/scripts}}} directory, and place your scripts there.  Then, make a cron configuration file that looks something like this.

{{{
PATH=/afs/hcoop.net/common/bin:/usr/local/bin:/usr/bin:/bin

09 0 * * 0   run-in-pagsh --fg ~/scripts/clean-mail
11 0 * * 0   run-in-pagsh --fg ~/scripts/remove-tmp
12 0 * * 0   run-in-pagsh --fg ~/scripts/weekly-comment-check
*/10 * * * * run-in-pagsh --fg ~/scripts/make-git-projects
}}}

The PATH line is needed so that you have access to {{{run-in-pagsh}}}.  Make sure you don't try to reference any other environment variables like {{{$HOME}}}, because cron will not expand them properly.

The first cron command runs something 9 minutes after midnight (aka the "0th" hour), every day of the month, every month, provided that it is Sunday (aka the "0th" day of the week).  In short: run something at 12:09 every Sunday.

The second and third commands are similar.

The fourth command runs something every 10 minutes.