well if its someone using your irc script you can add support to it but if is an addon you are planing to post on a public website you would prob have to have DDE control
but in the case its for a script for say updates etc you can do this
crude but it will do what your asking then but id recommend some if parsing if this is the case
from mirc.hlp file
Returns the command line that was passed to mIRC when it was first run.