I needed to setup a cron job to perform some maintenance which I wanted to automatically run on Sunday night since that’s usually a low traffic period. After looking up the right syntax in the manual for the eleventy-hundredth time, I realized I hadn’t written anything in a while, and I should probably jot this one down for later.
The normal syntax for a cron job item is usually right there in the editor window in a nearly unreadable dark blue font, but after using vim’s set background=dark option, turns into a nice light blue.
Based on that last line, the syntax is…
<minute> <hour> <day of month> <month> <day of week> <command>
And that means a cron job line that runs every Monday at 1:05 AM would then be structured like this:
5 1 * * 1 /the/command/goes/here
That “dow” option stands for “day of week” and is a number from 0 to 7, with the week starting and ending on Sunday. So here’s the listing:
- 0 – Sunday
- 1 – Monday
- 2 – Tuesday
- 3 – Wednesday
- 4 – Thursday
- 5 – Friday
- 6 – Saturday
- 7 – Sunday
Bottom line, if you want something to run on Sunday you can either use 0 or 7 in the “dow” column.