I'm always amazed at how many Unix features I assume are GNUisms or bashisms that turn out to be in POSIX and be much more portable than I've expected!
Yeah, for anything that I want to be portable, I explicitly run it with bash, dash, mksh, and heirloom sh. I figure that if it works in all of those, then the result is either truly portable... or nobody will ever notice:)
It also should really help that Debian, IIRC, actually sets /bin/sh to dash by default?
