title: git diff among two different repositories in two different folder
body: <p>I would like to know how can I get the git diff from 9.3.1-STABLE and TN-9.3.1-STABLE, with following folder/git  structure</p>
  
  <pre><code>root@build3:/tank/home/stable-builds/FN # git branch
    9.3-STABLE
  * 9.3.1-STABLE
  
  root@build3:/tank/home/stable-builds/TN # git branch
  TN-9.3-STABLE
  * TN-9.3.1-STABLE
  master
  </code></pre>
  
  <p>Any answer will be much appreciated.</p>