title: Commit changes only in one directory in Git
body: <p>I'm using Git 1.7.4.1 on Mac 10.6.6.  From the command line, how do I commit changes in only a single directory?  I added the directory by doing:</p>
  
  <pre><code>git add my-dir
  </code></pre>
  
  <p>but doing</p>
  
  <pre><code>git commit -a
  </code></pre>
  
  <p>brings up a list of all changes in my repo, and I only want to commit and push changes from <code>my-dir</code>.</p>