Create PDF on Windows without opening it?

[Chris Morris]

I'm looking into creating .ly lead sheets for many of the songs on one
of my sites, I've got custom automation that rips mp3s and oggs from
master wav files, so I'd like to throw the lilypond rendering step
into the mix, but currently running Lilypond 2.2 on Windows (cygwin)
automatically tries to open the pdf. I don't want it to automatically
open -- is there a way to control this? The command-line switches
don't seem to offer an option for this

-- 
Chris
http://clabs.org