The shutdown command is such run-of-the-mill command that most of us don\’t even realize that there are several options that you can pass to it to make it more useful. Aside from the well known -h to halt and -r to reboot, here are some other interesting options:

-c: cancel an already running shutdown process
-f: skip running fsck upon reboot
-F: force running fsck upon reboot
-k: don\’t really shutdown, just send the broadcast message (can be used as a warning).