How to implement a Linux daemon in bash that can be start/stop by `sudo service`?

[Ralf Mardorf]

On Sun, 18 Feb 2018 11:33:15 -0600, Peng Yu wrote:
>Can anybody provide a minimal working example so that I learn about
>it? [snip] a man page is not what I am looking for.

Much likely most subscribers to this list understand that manpages
don't help for several purposes. However, all your requests I read back
to 2016, I might not have read all of them, suffer from not explaining
what you want to accomplish.

To start or stop something when using upstart or systemd isn't an
issue, yes, I'm willing to give you an example, if you are willing to
post your "daemon in bash", and most important:

  Are you using upstart or systemd?