[chubot]

If the command is a daemon, that's basically retrying. But if you want to check the exit code, that's easy to do inside retry().

I totally agree with your second paragraph, that is why I'm working on fixing shell :)

http://www.oilshell.org/blog/

This entry in particular is relevant to your concerns:

http://www.oilshell.org/blog/2016/11/06.html