Linux: Programatically shutdown or reboot computer from a user-level process

Question

How do I programatically trigger a system shutdown or reboot in Linux? Preferably without requiring elevated privileges.

On older releases (e.g. Ubuntu 10.04) I could ca

Answer 1

The shutdown command. However, that requires root privileges on most systems.

Shutdown now:

shutdown -h now

Restart now:

shutdown -r now

man shutdown for more info.