title: Enthought Canopy: Where do os.environ variables come from?
body: <p>I have the following problem. I wanted to use the matplotlib package animation to save an mp4 video file. The save function has a dependency for generating the mp4 file, the ffmpeg external library. So I installed ffmpeg on a Mac osx 10.8 via Macports, and it got installed in <code>/opt/local/bin</code> . </p>
  
  <p>But now, running the script in canopy, the interpreter (ipython shell) can not see ffmpeg. I added the path to my .bash_profile, and I can run the program at my terminal, but when I type <code>os.environ['PATH']</code> the actual <code>PATH</code> of my shell was not added, and <code>/opt/local/bin</code> is not there. 
  If I try to run the script, I get this error:</p>
  
  <pre><code>/Users/alejandrodelacallenegro/Library/Enthought/Canopy_64bit/User/lib/python2.7/site-      packages/matplotlib/animation.py:695: UserWarning: MovieWriter ffmpeg unavailable
  warnings.warn("MovieWriter %s unavailable" % writer)
  </code></pre>
  
  <p>Any ideas to fix the problem? What I have to do to change an environmental variable that python sees at startup? Did anyone have the same problem?<br>
  Thanks.  </p>