title: Running Hello World using Node js Express in cloud 9IDE
body: <p>I successfully ran hello world in cloud 9 IDE using node JS express framework by replacing</p>
  
  <pre><code>app.listen(3000);
  </code></pre>
  
  <p>to</p>
  
  <pre><code>app.listen(process.env.PORT);
  </code></pre>
  
  <p>cloud 9 is asking me to use process.env.IP as the host for the scripts. Which file do I open to replace the host name to process.env.IP?</p>