spawn-command 
Spawn commands like child_process.exec does but return a ChildProcess.
Installation
npm install spawn-command
Usage
var spawnCommand = require('spawn-command'),
child = spawnCommand('echo "Hello spawn" | base64');
child.stdout.on('data', function (data) {
console.log('data', data);
});
child.on('exit', function (exitCode) {
console.log('exit', exitCode);
});