[kibwen]

I confess I don't really get this. Fish and Bash are different languages in the same way that Ruby and Perl are different languages. And if I want to run a Perl script, I don't try to run it in a Ruby interpreter, and I don't get grumpy at Ruby for not being source-compatible with Perl.

Which is to say, if you need to run a Bash script, run it via `bash foo.sh` rather than `./foo.sh`. There's no need to limit yourself to a worse shell just because there exist some scripts out there written in that shell's language.

[E39M5S62]

There's nothing even preventing the second form from working either. Just put the right shebang at the top of the script and it'll run through that interpreter. I've been on fish for a decade, but still write all my shell scripts in Bash. It's never been an issue.