title: pip permission error in virtualenv
body: <p>I try to install bottle inside <code>virtualenv</code>:</p>
  
  <pre><code> pip install bottle  
  </code></pre>
  
  <p>I get this error:</p>
  
  <blockquote>
    <p>OSError: [Errno 13] Permission denied: '/var/www/myapp/env/build'</p>
  </blockquote>
  
  <p>It seems like permission error, when I create the folder is in root, how can I sudo pip in virtualenv?</p>