title: Different version of npm when using sudo?
body: <p>when I tried to update npm, I found that command returns Permission deny:</p>
  
  <pre><code>npm install npm -g
  </code></pre>
  
  <p>Then I tried:</p>
  
  <pre><code>sudo npm install npm -g
  </code></pre>
  
  <p>Then npm has been updated, but when I tried npm -v and sudo npm -v, they show different version:</p>
  
  <pre><code>npm -v //3.10.10
  sudo npm -v //5.1.0
  </code></pre>
  
  <p>How can I make them always in the same version? It also happened on command 'node -v'. I am using fedora.</p>