Question: What are system commands, and how do you use them?
I'll be honest, my tags were about the firefox part, and not about system commands, because I assumed that part was more memetic (i mean, unless you're doing server stuff or computing thing in general, you are very unlikely to ever need to use them tbh).
System commands are basically little instructions that you give to the system, either to get the info of a system part, or to give an order to the system. Typically, this is something that you use on a server, but all Operating Systems (like Windows, Linux, Mac, etc.) have their own version that you can try right now. Go open the console (on windows, that's the Command Prompt), and you can start typing commands right away!
Like I said though, nowadays, this isn't something you're likely to come across unless you're dealing with some computing stuff (like servers, or coding, or networking, etc etc), and to be honest, I would need to know what you're trying to achieve for me to be able to help you anyway, but hopefully that answered your question!
Anyway in the meantime, here, just takes this Firefox link; no need to thank me, just spread it around, send it to all your friends and family.