title: jupyter notebook not working Mac despite being installed
body: <p>I have jupyter notebook installed but when I try and open it I get this error. Any idea why? </p>
  
  <pre><code>Traceback (most recent call last):
    File "/usr/local/bin/jupyter", line 8, in &lt;module&gt;
      sys.exit(main())
    File "/Library/Python/2.7/site-packages/jupyter_core/command.py", line 247, in main
      command = _jupyter_abspath(subcommand)
    File "/Library/Python/2.7/site-packages/jupyter_core/command.py", line 134, in _jupyter_abspath
      'Jupyter command `{}` not found.'.format(jupyter_subcommand)
  Exception: Jupyter command `jupyter-notebook` not found.
  </code></pre>