title: Is it safe to delete ~/.cache/pip directory
body: <p>I have limited space on my server, and I am thinking to delete the cache of the PIP. I am not sure if its safe to delete or not.</p>
  
  <pre><code>ls  ~/.cache/pip/
  </code></pre>
  
  <p>Contains following dir/files.</p>
  
  <pre><code>http  selfcheck.json  wheels
  </code></pre>
  
  <h2>Version</h2>
  
  <pre><code>$ pip -V
  pip 7.1.2 from /usr/local/lib/python2.7/dist-packages/pip-7.1.2-py2.7.egg (python 2.7)
  </code></pre>
  
  <p>Please advise. </p>