There is no straight forward way to schedule a cron job so that a certain command gets executed biweekly, let’s say every 2 sunday nights…
To be able to do this, you need to extend your cron command with a command that tests the day of the week.
In my case I needed to perform a ‘clone MySQL database’ on the 2nd and 4th sunday of each month to a sandbox environment.
This is how I’ve implemented this:
30 2 8-14,22-28 * * test $(date +%u) -eq 1 && sh /root/clone_to_sandbox.sh
You see that the cron job itselfs is scheduled to happen from:
The 8th until 14th of each month and from the 22nd until the 28th of each month.
When executing, I test if the day is the 1st of the week (Sunday = day 1 of the week). When this result is positive, the shell script will be executed.
If the cron time/date commands are unfamiliar, there is an interactive tutor at http://www.dataphyx.com – put in any combination of crontab timing parameters, get back a list of future run-times.
Very nice link! Tnx!
http://www.easycron.com/generator/cronjob can generate a correct crontab line, hope it helps.
really good, thats one step how enjoyed schedule cron
thank you