title: 'Brew unlink node' error
body: <p>I am going to downgrade the current node version to v6.13.0 on MacOS. So, I run this command first.</p>
  
  <pre><code>brew unlink node
  </code></pre>
  
  <p>But I am having this error.</p>
  
  <pre><code>Error: No such keg: /usr/local/Cellar/node
  </code></pre>
  
  <p>Let me know how I fix this error.</p>