title: On GitLab, how to compare a file of two different commits
body: <p>On GitLab, how to compare a file of two different commits? I know that that on command line git, the command is:</p>
  <pre><code>git diff commit1 commit12 -- file_name
  </code></pre>
  <p>What is the link format to do this on GitLab?</p>
  <p>See my related <a href="https://stackoverflow.com/questions/48525235/on-gitlab-how-to-view-a-file-as-of-commit-ref">question</a></p>