Stdin, stdout and stderr of asynchronously created Node.js child process

What's the correct way in Node.js to create child process asynchronously so that it's stdin, stdout and stderr are same as parent's. Should I use child_process.exec() or child_process.spawn(). Node.js version is 6.10. Also, I kill the parent process soon after creating child process, so e.g. stdout cannot be printed with any callback function.

via Jirka Ylönen