var sys   = require('sys'),
    spawn = require('child_process').spawn,
    ls    = spawn('ls', ['-lh', '/usr']);

ls.stdout.addListener('data', function (data) {
  sys.print('stdout: ' + data);
});

ls.stderr.addListener('data', function (data) {
  sys.print('stderr: ' + data);
});

ls.addListener('exit', function (code) {
  sys.puts('child process exited with code ' + code);
});

//Question: Why doesn't the ls child process terminate before event listener for "exit" has been added?