screensaver or APM control via commandline?

[Charles Jones]

I have a linux laptop connected to a large screen display that shows 
informational items (what it is doesn't matter) that are only viewed 
from 7am-6pm. To conserve energy and reduce screen wear I would like for 
the display to go to sleep after the PC has been idle for X hours.

The GUI screensaver and Power Management controls do not allow you to 
select any times greater than 2 hours of idle time.  If I could set it 
for 12 hours, I could just move the mouse when I walk by it first thing 
in the morning, and 12 hours later it would automatically go to sleep 
until the next day.

I would prefer to have APM blank the screen via a cron job, then I could 
just "set it and forget it".

I remember there was a command-line way to set screenblanking time of 
consoles, but how does one do it in runlevel 5?