title: How to symlink file using homebrew and how to delete a file
body: <p>I installed PIL and then I installed libjpeg and I get the following errors:</p>
  
  <pre><code>    jpeg8-d is already installed, it's just not linked
      Could not symlink file: /usr/local/Cellar/jpeg/8d/bin/wrjpgcom
      Target /usr/local/bin/wrjpgcom already exists. You may need to delete it.
      To force the link and delete this file, do:
      brew link --overwrite formula_name
  </code></pre>