This is offtopic so i'll reply to it first :-)

I don't have access to a FreeBSD system, and I'd be interested to learn how different it could be from linux & solaris

Because bourne shell is so important, the behavior should be identical (POSIX), but I can't swear to it. I've encountered /bin/sh scripts containing some bash-specific syntax (i.e., poorly written shell scripts). These worked on linux but not FreeBSD because FreeBSD's /bin/sh was more anal about POSIX correctness.