title: How would I get a cron job to run every 30 minutes?
body: <p>I'm looking to add a <code>crontab</code> 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.</p>
  
  <pre><code>*/30 * * * *
  </code></pre>
  
  <p>What string do I need to use?</p>
  
  <p>The cron is running on OSX.</p>