title: Show only history of one branch in a Git log
body: <p>I am using Git for my project and trying to follow best practice:</p>
  
  <ol>
  <li>I work on a <em>topic branch</em></li>
  <li>When ready, I merge the <em>topic branch</em> into my <em>dev</em> branch using <code>git merge --squash</code>. This keeps my <em>dev</em> branch clean.</li>
  <li>Whenever the <em>dev</em> branch is stable and the team decides it's time for a release, we merge the <em>dev</em> branch into the <em>master</em> branch, <strong>without</strong> using squash, and tag that commit as a version release.</li>
  </ol>
  
  <p>This should keep our history, and using gitk, we can see where all of the commits come in. However, I want to be able to see <strong>only</strong> the commits applied to the <em>master</em> branch. I have tried:</p>
  
  <pre><code>git log master
  git show-branch
  </code></pre>
  
  <p>None of these show <strong>just</strong> the history of the <em>master</em> branch. Is there a way to easily do this?</p>