I can see both sides:
StackOverflow, because (1) programmers are much more likely to be able to relate to them and so be able to answer them, and (2) more often than not, the users who customize BASH are programmers, and (3) I've seen lots of BASH questions on StackOverflow.
SuperUser, because (1) it's just a computer program and has nothing to do specifically with programming, and (2) I've seen some BASH questions on SuperUser too.
I've gone with the first option, and it seems like there is agreement and disagreement on both sides.
Should there be something with regards to this on the FAQ or somewhere? Also, where should such a question go, and why?