title: Uninstalled IPython on Ubuntu but can still be used
body: <p>I tried to install rpy2 earlier today, to use IPython Notebooks in conjunction with R. I'm using Ubuntu 12.04. However, I had issues with using the magics extension, so went off down a rathole to resolve...</p>
  
  <p>I've tried to uninstall IPython via the command</p>
  
  <pre><code>sudo apt-get remove --auto-remove ipython
  </code></pre>
  
  <p>... which seemed to work correctly, and from looking in <code>/usr/lib/python2.7/dist-packages</code>, I manually can't see an IPython directory. I double checked the uninstallation method worked:</p>
  
  <pre><code>me@my_laptop:/usr/lib/python2.7/dist-packages$ sudo apt-get remove -auto-remove ipython
  Reading package lists... Done
  Building dependency tree       
  Reading state information... Done
  Package ipython is not installed, so not removed
  0 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade.
  </code></pre>
  
  <p>However, I can go into a terminal and type <code>ipython</code> I get the following -- note that I can import the package as well:</p>
  
  <pre><code>me@my_laptop:/usr/lib/python2.7/dist-packages$ pwd
  /usr/lib/python2.7/dist-packages
  me@my_laptop:/usr/lib/python2.7/dist-packages$ ipython
  Python 2.7.3 (default, Dec 18 2014, 19:10:20) 
  Type "copyright", "credits" or "license" for more information.
  
  IPython 3.0.0-b1 -- An enhanced Interactive Python.
  ?         -&gt; Introduction and overview of IPython's features.
  %quickref -&gt; Quick reference.
  help      -&gt; Python's own help system.
  object?   -&gt; Details about 'object', use 'object??' for extra details.
  
  In [1]: import IPython
  
  In [2]: IPython
  Out[2]: &lt;module 'IPython' from '/usr/local/lib/python2.7/dist-packages/IPython/__init__.pyc'&gt;
  </code></pre>
  
  <p>NB I tried to use the comment by kermit666 in, butthis did not seem to help: <a href="https://stackoverflow.com/questions/20454921/broken-ipython-notebook-install-ubuntu-13-10-how-to-force-reinstall">Broken IPython notebook install Ubuntu 13.10 how to force reinstall</a> </p>
  
  <p>Does Python cache its packages somehow, like in a database, that I need to 
  update somehow? I don't understand how it is loading something that in theory has been deleted?</p>