How would I get a cron job to run every 30 minutes?

Question

I\'m looking to add a crontab entry to execute a script every 30 minutes, on the hour and 30 minutes past the hour or something close. I have the following, but

Answer 1

Try this:

0,30 * * * * your command goes here

According to the official Mac OS X crontab(5) manpage, the / syntax is supported. Thus, to figure out why it wasn't working for you, you'll need to look at the logs for cron. In those logs, you should find a clear failure message.

Note: Mac OS X appears to use Vixie Cron, the same as Linux and the BSDs.