Hi, mz043.
As far as I know, you have two options:

- One is to create a chroot jail for your users (As you've been told). This involves several tasks: create a dummy "root filesystem", copy libs, binaries, etc... The use of sudo, and some shell scripting among others. There are lots of info on the Net, depending on your OS.

- The other is the use of a restricted shell. I don't know what OS you are using but perhaps a "man -k restricted" would give you some clues

Regards.