Add the following code toward the top of your script
#change this to what ever you want it to say when a user presses ctrl-c
echo "You cannot use that command"
This defines a function that you will need to prevent users from pressing ctrl-c
I'm assuming that your script contains some type of loop, to allow users to execute commands or something of that nature probably an until statement
Right under where this loop starts (whatever it may be) add the following
What this does is call the function named 'nobreak' every time the user presses ctrl-c
btw: Could you post the code so i can be more specific on where these entrys should go.