title: ubuntu: uninstall matplotlib with pip won't work
body: <p>I'm on Ubuntu and I neeed to <strong>uninstall</strong> <code>matplotlib</code>, which I installed as an ubuntu package and later upgraded with <code>pip</code>. 
  The usual command doesn't work:</p>
  
  <pre><code>$ sudo pip uninstall matplotlib
  Can't uninstall 'matplotlib'. No files were found to uninstall.
  </code></pre>
  
  <p>What should I do?</p>
  
  <p>Extra info:</p>
  
  <pre><code>~$ pip matplotlib --version
  ERROR: unknown command "matplotlib"
  me@me:~$ pip show matplotlib
  ---
  Name: matplotlib
  Version: 1.4.0
  Location: /usr/local/lib/python2.7/dist-packages
  Requires: numpy, six, python-dateutil, pyparsing, nose, mock, nose, mock
  
  $ pip --version
  pip 1.5.4 from /usr/lib/python2.7/dist-packages (python 2.7)
  </code></pre>