Today when I was reading the man page of shutdown, it made me confused a lot. Take -H as example. I just could not understand the "after it has been brought down". What does it specify exactly? What is the meaning of "been brought down"?
OPTIONS
-r Requests that the system be rebooted after it has been brought down.
-h Requests that the system be either halted or powered off after it has been brought down, with the choice as to which left up to the system.
-H Requests that the system be halted after it has been brought down.
-P Requests that the system be powered off after it has been brought down.
-c Cancels a running shutdown. TIME is not specified with this option, the first argument is MESSAGE.
-k Only send out the warning messages and disable logins, do not actually bring the system down.