title: How can the default node version be set using NVM?
body: <p>I have installed nvm (ubuntu with zsh shell) with two node version: <code>v6.11.5</code> and <code>v9.0.0</code> and the default version in nvm is the <code>v9.0.0</code></p>
  <p>Every time I need to change the node version</p>
  <pre><code>$ nvm list
           v6.11.5
  -&gt;       v9.0.0
           system
  default -&gt; node (-&gt; v9.0.0)
  node -&gt; stable (-&gt; v9.0.0) (default)
  stable -&gt; 9.0 (-&gt; v9.0.0) (default)
  
  
  $ nvm v6
  </code></pre>
  <p>How could I change the nvm version default to define <code>v6.11.5</code>?</p>