The
shutdown(8) command logs you out, drops into single user mode (shutting down all running processes except
init(8)), then halts the system.
If requested by the -p operand, it will also power down the system, if the hardware supports automatic power down, but that is dependent upon the system's BIOS and the method it uses for software power down control. Issuing:
# shutdown now
Will drop from multiuser to single user mode. It will not halt the system nor power down the system unless the -h or -p operands are used or the variable
powerdown is set to YES in /etc/rc.shutdown.
A system which is halted can be rebooted just by pressing any key on the keyboard.