In this short article I would like to remind you few useful keywords which you can use to describe your cron jobs in simple way.
Their names sufficiently describes how specified keyword works, but I prepared a short table with description where you can also find equivalent for keyword in regular “cron language” and how it acts.
Keyword | Equivalent | Description |
@yearly | 0 0 1 1 * | Run job every year |
@daily | 0 0 * * * | Run job every day |
@hourly | 0 * * * * | Run job every full hour |
@reboot | Run job at system startup |
To edit your crontab, you use:
crontab -e
To see actual crontab for your current user:
crontab -l
Here is a real-life example of keywords usage in crontab:
@daily /usr/sbin/cron-apt
@reboot /usr/sbin/cron-apt
It runs cron-apt (auto update tool for your aptitude) command every day and after every reboot.
You can read more about cron-apt here.
DD