If I had a question solely bash or bash-related, would AskDifferent be the right place to ask? Or is there another community more appropriate for that?
For OSX specific bash questions e.g. how to set environment variables for GUI and what files are read when a Terminal starts this is really the main site (SuperUser is also OK with these as any OSX question here is also on topic there)
Bash is also on topic on Superuser - Unix & Linux - Ubuntu and no doubt others as a user. Some question re programming bash could be on topic for Stack Overflow but I think that is not going to be the best site.