linux - 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 it doesn't seem to run on 0.

*/30 * * * *

What string do I need to use?

The cron is running on OSX.

Answer 1

Do:

0,30 * * * * your_command