Banning normal user form doing shutdown at login prompt

[vickey_20]

Hello
I have noticed that once you are at the loging prompt (normal user or root) If one presses CTRL+ALT+DEL the machine boots up again. It seems stupid as to why would some one just logged in would reboot the machin ( unless dont know what's there on their mind). How to disable and force anyone to 1st login and after having sufficient permission perform the shutdwon.

[b2bwild]

Ctrl + Alt + Del is Important shortcut,
Some times its like fire exit, when you have to reboot system quickly at any stage safely, even while booting.

The default command used is shutdown -r

But you can edit the behaviour of Ctrl+Alt+Del in /etc/inittab file
If you are on Ubuntu or its variants
The /etc/inittab file is separeted in multiple files in /etc/event.d/ directory
The file is /etc/event.d/control-alt-delete

start on control-alt-delete

exec /sbin/shutdown -r now "Control-Alt-Delete pressed"

[devils casper]

There are a lot of ways to restrict Regular Users.
You can disable Shutdown option at Login Screen, disable Power button and remove shutdown option from Menu for Regular Users.

Check the contents of /etc/inittab file.

ca::ctrlaltdel:/sbin/shutdown -t3 -r now

Disable it :

ca::ctrlaltdel:/bin/echo

[vickey_20]

If you are on Ubuntu or its variants

Well I'm on ubuntu only for a short period of time as I have messed up my laptop. But are there lot of difference between variants of Linux.

ca::ctrlaltdel:/sbin/shutdown -t3 -r now

Disable it :

ca::ctrlaltdel:/bin/echo

But doing the above code like what b2wild said won't provide user the authority to quickly shutdown that system when he has not reached the login prompt ( Ya its a kind of paradox statement to my own question but that time I didn't think of rebooting before starting i.e reaching prompt). But can this be done , Allowing a user to do a reboot before reaching the prompt but once on the login screen forced to enter and manually do shutdown ( Totally like a dreamy situation).