title: Is there any difference between `git merge origin master` and `git merge origin/master`?
body: <p>Can any body explain the difference between <code>git merge origin master</code> and <code>git merge origin/master</code>?</p>
  
  <p>I did accidentally did <code>git merge origin master</code>.  If it is different, what is the command to reset that merge?</p>