exiting, line() output, and returning from laravel 5.x artisan handle() command

I am writing artisan commands successfully but I am uncertain about the proper way to end the command, or specifically the handle() method.

What is the proper way to end the command? Should I normally return something, or exit with a value?

I want to write the command in such a way as it can be piped to an argument on another command etc. but also handle exiting with error codes. Thanks.

via Chebli Mohamed