For many years I, and some other *NIX admins I know, have advocating writing shell scripts to Bourne standard if you think that there might ever be apossibility it could run on other systems. We are primarily SysAdmins so scripts aren't generally for use outside of the systems we admin. However, a good script has a way to getting out on it's own. If you absolutely need some bash or ksh extension, document it. One of the best things you can do for portability is to use comments in your script.