This looks like a neat program. (As someone who has never used ruby): how do I run it? This isn't obvious to me.

Leto is talking to Paul, and he is talking about either a region or a chemical process that is important for the production of film stock. then he sardonically says something like, (paraphrasing):

"Film stock is very important. we have the finest propaganda offices. The people must learn how well I govern them. How would they know if we didn't tell them?"

he means it sarcastically, but propaganda is important to keep useful people on the planet and to win the general populace over. Leto knows he's backed into a corner on Arrakis and he's focusing on what he can.

I also could only find the part i posted originally online, its not one of the more frequent quotes from the book.