Molly-Guard is a usefull and easy to use tool. It prevents you from accidentally shutting down your Linux.
This is very good when you are connected as root on ssh and by mistake you shutdown the remote server instead of your local computer. I think this happened to everyone (at least once).
Molly-Guard asks the hostname of the station you want to shut down, even if you are connected or not to ssh.
How to install Molly-Guard:
$ sudo apt-get install molly-guard
If you want to install Molly-guard on Fedora or OpenSuSE, you need to convert it into the .rpm format first.
$ sudo shutdown now
W: molly-guard: SSH session detected!
Please type in hostname of the machine to shutdown: naboo
If you type a wrong hostname, nothing will happen.