How to Run a Cron Job Only on Sunday (or Any Other Day)

By Lowell Heddings on July 21st, 2017

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.