title: sudo: pip: command not found in CentOS
body: <p>I use CentOS and I installed pip to <code>/usr/local/python-dir/bin/pip</code>. I made a link to <code>/usr/local/bin/pip</code>. Then I executed <code>sudo pip install xxx</code>, it reported an error like this:</p>
  
  <pre><code>sudo: pip: command not found
  </code></pre>
  
  <p>I see <code>$PATH</code> is all right:</p>
  
  <pre><code>/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin
  </code></pre>
  
  <p>However, I can only execute pip this way:</p>
  
  <pre><code>sudo /usr/local/bin/pip install xxx
  </code></pre>
  
  <p>How can I configure PATH or something else? Thanks a lot.</p>