title: how to checkout a specific commit from git
body: <p>My code isn't working and it seems I have merged a wrong piece of code in my <code>master</code> branch. I am unable to pin point the issue and thus I want to pull specific commits one by one to find out which version was working just before the wrong commit.</p>
  
  <p>How could I pull a specific commit? Eg, On Bitbucket, I see a merge with id <code>9ce920d</code> on branch <code>test</code> but I don't know how to pull this merge.</p>