title: Can no longer use npm command after trying to update
body: <p>I was trying to install yeoman but it threw an error regarding self signed certificates.</p>
  
  <p>I looked this up and I found out I had to upgrade node.</p>
  
  <p>Upgrading node however threw this: (forgot to use sudo with it...)</p>
  
  <pre><code>npm ERR! error rolling back Error: EACCES, unlink '/usr/local/lib/node_modules/npm'
  npm ERR! error rolling back  npm@1.4.4 { [Error: EACCES, unlink '/usr/local/lib/node_modules/npm']
  </code></pre>
  
  <p>After this I couldn't use npm anymore. It couldn't be found:</p>
  
  <pre><code>/usr/local/bin/npm: No such file or directory
  </code></pre>
  
  <p>Trying to reinstall with brew:</p>
  
  <pre><code>It appears you already have npm installed at /usr/local/lib/node_modules/npm
  </code></pre>
  
  <p>Tells me to npm uninstall but I can't use npm anymore.</p>
  
  <p>The error message is more detailed but I think the part about "unlinking" is the main thing. How do I go about linking it back up and also why was such a weird error thrown?</p>
  
  <p>EDIT: also ran <code>npm config set ca ""</code> before trying to update node.</p>