Events.js: 72 error - Error running my first global app with express

Question

I did the global installation of express on Ubuntu (and on my Mac too) using

npm install -g express 

Then I created my app using the command:

express -se hello_express

I entered the application directory and typed:

npm install

When I try to run Node using the command

node app.js

he accuses the following error:

events.js:72
    throw er; // Unhandled 'error' event
          ^
Error: listen EADDRINUSE
  at errnoException (net.js:901:11)
  at Server._listen2 (net.js:1039:14)
  at listen (net.js:1061:10)
  at Server.listen (net.js:1135:5)
  at Object.<anonymous> (/caminho_da_aplicacao/hello_express/app.js:36:24)
  at Module._compile (module.js:456:26)
  at Object.Module._extensions..js (module.js:474:10)
  at Module.load (module.js:356:32)
  at Function.Module._load (module.js:312:12)
  at Function.Module.runMain (module.js:497:10)

I’m starting now with "Node + express," so I’d like to know if anyone’s been through this, if I’m doing something wrong, and how do I solve it.

Answer 1

Error: listen EADDRINUSE

The port the express will use is already being used, choose another: the port is defined by that line app.set('port', process.env.PORT || 3000); in the app.js, soon change the variable PORT.

As has been shown on this Stackoverflow issue you will also encounter this error when you close your app unexpectedly, which is without the chance of the application releasing the ports. If this is your case there are the answers.