Command Line Broadcast/Admin Massage

I am trying to set up a task in windows 7 Pro, running Openfire3.9.1; that would execute a program/script that would send out a message to all users (preferably only users logged in) when the system is about to go down for maintenance. We do have the broadcast 1.9.0 plugin installed as well.

It is preferable to be Command Line driven, as we can’t have automated “point and click” software.

I also forgot to mention the messenger client currently being utilized is pidgin 2.10.9