title: can't install matplotlib using pip
body: <p>I'm on Ubuntu 14.04, and have been trying to install matplotlib using pip. I'm using Python 2.7.6. However, whenever I run "sudo pip install matplotlib", I get the following errors:</p>
  
  <pre><code>Downloading/unpacking matplotlib
  Downloading matplotlib-1.4.0.tar.gz (51.2MB): 51.2MB downloaded
  Running setup.py (path:/tmp/pip_build_root/matplotlib/setup.py) egg_info for package matplotlib
    ============================================================================
    Edit setup.cfg to change the build options
  
    BUILDING MATPLOTLIB
              matplotlib: yes [1.4.0]
                  python: yes [2.7.6 (default, Mar 22 2014, 22:59:56)  [GCC
                          4.8.2]]
                platform: yes [linux2]
  
  REQUIRED DEPENDENCIES AND EXTENSIONS
                   numpy: yes [version 1.8.1]
                     six: yes [using six version 1.5.2]
                dateutil: yes [using dateutil version 2.2]
                 tornado: yes [using tornado version 4.0.1]
               pyparsing: yes [using pyparsing version 2.0.2]
                   pycxx: yes [Couldn't import.  Using local copy.]
                  libagg: yes [pkg-config information for 'libagg' could not
                          be found. Using local copy.]
  Traceback (most recent call last):
    File "&lt;string&gt;", line 17, in &lt;module&gt;
    File "/tmp/pip_build_root/matplotlib/setup.py", line 154, in &lt;module&gt;
      result = package.check()
    File "setupext.py", line 940, in check
      if 'No such file or directory\ngrep:' in version:
  TypeError: argument of type 'NoneType' is not iterable
  Complete output from command python setup.py egg_info:
  ============================================================================
  
  Edit setup.cfg to change the build options
  </code></pre>
  
  <p>I've tried installing all the dependencies listed under "required dependencies and extensions", but I still get the same error.</p>