title: Why do I need the "master" in git merge origin/master?
body: <p>The convention when using git and you want to get changes from the server is:</p>
  
  <p><code>git fetch</code></p>
  
  <p><code>git merge origin/master</code></p>
  
  <p>I know there is also <code>git pull</code>, but my specific question is about the syntax <code>origin/master</code>. What does the <code>master</code> part do? If I just do <code>git merge origin</code> (without the <code>master</code>) it seems to work. I know <code>master</code> is a branch, but if I'm tracking more than one branch of a remote, would the normal use case be to merge all of them?</p>