title: gatsby --version > -bash: gatsby: command not found
body: <p>I use mac and I installed gatsby-cli by:</p>
  
  <pre><code>npm install --global gatsby-cli
  </code></pre>
  
  <p>and 'npm root -g' command prints:</p>
  
  <pre><code>/usr/local/lib/node_modules/npm/lib/node_modules
  </code></pre>
  
  <p>npm successfully installed gatsby but,
  I cannot run gatsby command (gatsby --version, gatsby --help)
  Whenever I type and run "gatsby --version" it prints:</p>
  
  <pre><code>-bash: gatsby: command not found
  </code></pre>
  
  <p>Is there any way I can fix this problem??</p>