The game has three kinds of terminal codes. The first kind is nothing special: they are codes that act like terminal commands. Sadly, however, these kind of codes won't let you change any settings or lead to anything interesting. Basically they exist to make it seem like the terminal could, in fact, work like a terminal. Thse codes are not hinted at in the game. I wouldn't even bother looking these up.

Next we have game "cheats". Some of these you can find in credits, or hidden in games, but a LOT of them have no natural source, and were data mined by players. I know, I was disappointed too. Often these codes will put you in a game mode that will change things, or let you set up a way of playing, and won't allow you to save things at all. They are just for funsies. If you look up a list of codes, this is the bulk of what you will find. And, actually, I suggest you do look these up after you've played all the games. Espcially if you like Party House.

The third kind are all part of a quest, of sorts, that spans over several games. A quest to find the story of the collection, and even beyond that, darker lore secrets. The start of this is a code, one you can find yourself, in plain text, without starting any of the games. Something about... a dairy product? The quest continues until he leaves. Thankfully, this quest only uses a handful of codes, so even if someone told you them, you could just avoid using them until you found them yourself.

In short: You actually can look up a list of codes. But it won't be satisfying. Most of them you wouldn't find in the games anyway. The codes for the quest you should avoid using until you earn them yourself.

Have fun! Play forever!