Gabriel gives you tab-completion for god commands, options, tasks, and groups in bash.
Run gabriel-install, follow the directions given, and you're good to go.
$ god st<TAB>
start status stop
$ god status
atest: up
btest: up
ctest: up
$ god start <TAB>
atest btest ctest
This is currently very alpha and honestly, I have little acquaintance with shell scripting.
If you can find a way to make Gabriel's completions even better, please do send a pull request.