title: How to use changed_when with ansible shell module?
body: <p>I have a complex shell script that is run by ansible and I do want to communicate from it to ansible when changes were made on the system, so Ansible will know that the host was modified.</p>
  
  <p>This is achieve by using <code>changed_when: condition</code> but the problem is that I cannot really rely on a specific exit code to be used for success_with_change instead of success_without_change.</p>
  
  <p>What other options are available? Can I use <code>register:</code> and use the registered variable inside <code>changed_when:</code> in order to check for a placeholder string in the output?</p>