How to show a file in Finder in LW?

My next obstacle is how to show a file in Finder in LW?

LW probably does not have the function, but does anybody know if 
there is OS X unix command that would do the work?

Then we could use it in this way:

(defun reveal-in-finder (pathname)
    (sys::call-system <unix command + pathname>))

Pekka