title: npm upgrade with homebrew
body: <p>When node (v.0.10.33) is installed with homebrew (v. 0.9.5), at one point it says: </p>
  
  <pre><code>==&gt; Caveats
  If you update npm itself do NOT use the npm upgrade command
  Instead execute:
  npm install -g npm@latest
  </code></pre>
  
  <p>So, what exactly is <code>npm upgrade</code> and what is the difference with <code>npm install -g npm@latest</code>? </p>
  
  <p><strong>-- edit 2015</strong></p>
  
  <p>the problem doesn't exist anymore with the current version of node. (but I never had an answer to what <code>npm upgrade</code> is?)</p>