title: Installing python2 modules if default python is python3
body: <p>I have installed Anaconda3 to get all the modules for python 3. However there are some codes which must be run in python 2. I don't have any installed python 2 module. I tried installing numpy via:</p>
  
  <pre><code>pip2.7 install numpy
  </code></pre>
  
  <p>But got an error:</p>
  
  <blockquote>
    <p>OSError: [Errno 13] Permission denied:
    '/usr/local/lib/python2.7/dist-packages/numpy'</p>
  </blockquote>
  
  <p>Whenever I want to install a module I get the same error, for instance, with the NLTK module I get</p>
  
  <blockquote>
    <p>OSError: [Errno 13] Permission denied:
    '/usr/local/lib/python2.7/dist-packages/nltk-3.2.1.dist-info'</p>
  </blockquote>
  
  <p>How can I fix this?</p>
  
  <p>Thanks!</p>