// http://nodejs.org/api.html#_child_processes
var sys = require('sys')
var exec = require('child_process').exec;
var child;
// executes `pwd`
child = exec("pwd", function (error, stdout, stderr) {
  sys.print('stdout: ' + stdout);
  sys.print('stderr: ' + stderr);
  if (error !== null) {
    console.log('exec error: ' + error);
  }
});
// or
var sys = require('sys')
var exec = require('child_process').exec;
function puts(error, stdout, stderr) { sys.puts(stdout) }
exec("composer network ping -c admin@sample", puts);