title: How to compare files from two different branches
body: <p>I have a script that works fine in one branch and is broken in another. I want to look at the two versions side-by-side and see what's different. Is there a way to do this?</p>
  <p><strong>To be clear</strong> I'm not looking for a compare tool (I use <a href="https://en.wikipedia.org/wiki/Beyond_Compare" rel="noreferrer">Beyond Compare</a>). I'm looking for a Git diff command that will allow me to compare the master version to my current branch version to see what has changed. I'm not in the middle of a merge or anything. I just want to say something like</p>
  <pre><code>git diff mybranch/myfile.cs master/myfile.cs
  </code></pre>