Good table of differences below.
http://www.faqs.org/faqs/unix-faq/sh...l-differences/
There are some subtle differences. If you're a crusty KSH scripter (like me), you'll see some issues crop up. Have alot of kshell scripts that poll devices for portcounts and insert into perl DBI connector, biggest thing I've found have been syntax (set, export, for, array, etc.)
FYI, you can compile BASH for HPUX 11x, Solaris 8,9,10.
My peers give me a hard time quite a bit (i.e., "good to see you're using something out of the 90's!).....