title: NodeJS. Express 4. How to define environment
body: <p>How can i define enviroment at NodeJS, Express4?</p>
  
  <p>Don't work. Output error in console.</p>
  
  <pre><code>NODE_ENV=production node app.js
  </code></pre>
  
  <p>EDIT:</p>
  
  <p><a href="http://rghost.net/57634264/image.png" rel="nofollow">http://rghost.net/57634264/image.png</a></p>
  
  <p>"NODE_ENV" is unknown command.</p>