So i am using the guest account for a kiosk. So far it is great  because it locks the home directory down to a folder in /tmp. But it has some down sides. I can't seem to find a way to set the default shell to anything other then bash. I want a way to give that user a restricted shell in case the user finds a way to get access to a shell. Does anyone know where to modify the script that creates the guest user account is?