Bash Shell

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.

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Lowell is the founder and CEO of How-To Geek. He’s been running the show since creating the site back in 2006. Over the last decade, Lowell has personally written more than 1000 articles which have been viewed by over 250 million people. Prior to starting How-To Geek, Lowell spent 15 years working in IT doing consulting, cybersecurity, database management, and programming work.
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