simple answer.
only root/admin should have permission to change these files.
if you need other users to have access to the shell, you need to change that users shell interface (for security reasons, e-smith has the shell interface switched off by default for 'non-superusers'). to do this, log in to the shell as root and execute the command 'chsh' as follows:
chsh -s /bin/bash username
where username is the users login. warning - non privledged users may not have access to the php/mysql files; this is a file permissions issue. general rule of thumb is that if they don't have access, they probably shouldn't.
if you've got your heart set on giving users access, and this hasn't helped, look yourself up some info regarding php, mysql, linux security, etc... a good place to start is
www.linuxdoc.orghoping this has helped,
zac