program comand line - what is it?

ok, I'm almost sure that it soemthing to do with making a function into a code that you can use yourself in a game as if it was a command.

What I don't get is how to use it.

I'm sure as soon as I figure out what it is I feel a little stupid, but I guess it's a good idea to learn now instead of later.

Hope I gave you a simple task

Andrew =)