As far as starting things goes, you should look into the at command, or (more standard) cron. Try googling it, but to get you started:
http://www.webmasterworld.com/forum23/80.htm
http://www.redhat.com/support/resour...cron/cron.html
As far as closing it goes, you could do a killall 'name' , and then schedule that in the same way. skill also works by name as well, i think, and is more complicated... Anyway, for a better description than i can give, say man skill and man killall. I think killall is the one you want tho. Hope that helps anyway, i think if you do a little work to get the rest of the information it'll stick in your head better