Linux - Shutdown halt server

If you want to shutdown a server from the box without it coming back up again you can issue the shutdown command with the -h flag as shown below:

$ shutdown -h now
Broadcast message from root (pts/1) (Fri Jul 8 15:11:33 2011):
The system is going down for system halt NOW!

This should only be issued by the root user and will terminate all sessions to the box. To restart the box you will need to manually switch it back on. The shutdown -r now command is preferred, as this will bring the box down and restart. Use the -h command with caution and only when necessary.