Is it possible to restrict a users access to only a few shell commands.

I need to restrict specific users access to only a few shell commands. Some users maybe only need commands like ls, cat, ping, sudo and su, and I like to make sure that NO other commands are avaliable to them. Is this possible ?. I have thought about using chroot, but if the user uses su, he need to be able to have access to all the commands the new user has. Is there a super simple and maybe more secure shell then bash ?. ------------------------------------------------- Med venlig hilsen Bo Jacobsen SystemHouse Vesterbrogade 149, 1620 København V Tlf: 70 21 18 70 Fax: 33 25 05 71 e-mail: Bo@SystemHouse.dk