system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What’s the practical difference between an open source and a proprietary operating system?

Like I know something like Linux is an open-source and I know that windows is proprietary but what does that mean? Also what is Ubuntu and how does it relate to Linux?
gpt
Software is like a cake. Proprietary software is made according to a recipe that's kept secret by the baker. It may taste great, but if you're allergic to hazelnut, you'd have to ask (and trust) the baker about it, or do a chemical analysis, or just try and hope for the best.

Open source software gives you a copy of the recipe along with the cake, so you can check the ingredients, or you can make your own cake.

Linux is just the naked cake. There's also a variety of sugarcoating and sprinkles and candles for it (most of them themselves open source), but not all of them work together well. A distribution like Ubuntu offers you ready-made package deals that are (somewhat) tested to go together.