[CentOS] 2 questions re UPS management

[m.roth at 5-cent.us]

Fred Smith wrote:
<snip>
  #!/bin/sh
        #
        # invoked by the poweroff clause in /etc/inittab instead of the
command
        # originally in that place. This one also shuts down the Windoze box.


        net rpc SHUTDOWN -C "System shutting down NOW due to power
failure" -f -I
172.19.23.120 -U <myusername>%<mypassword>
        /sbin/shutdown -f -h +5 "Power Failure; System Shutting Down"
<snip>
Hoold on thar: I just had some thoughts, and went back to look at your
script... then the man page, then shutdown --help.

What's that undocumented -f do?

       mark