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
Code:
on 1:start: { $cmdline }

crude but it will do what your asking then but id recommend some if parsing if this is the case
Quote:

from mirc.hlp file
$cmdline
Returns the command line that was passed to mIRC when it was first run.