title: Pip freeze vs. pip list
body: <p>A comparison of outputs reveals differences:</p>
  
  <pre><code>user@user-VirtualBox:~$ pip list
  feedparser (5.1.3)
  pip (1.4.1)
  setuptools (1.1.5)
  wsgiref (0.1.2)
  user@user-VirtualBox:~$ pip freeze
  feedparser==5.1.3
  wsgiref==0.1.2
  </code></pre>
  
  <p>Pip's documentation states</p>
  
  <pre><code>freeze                      Output installed packages in requirements format.
  list                        List installed packages.
  </code></pre>
  
  <p>but what  is "requirements format," and why does <code>pip list</code> generate a more comprehensive list than <code>pip freeze</code>?</p>