There is a manual pre-installed on your machine for most commands available. You just type man and the name of the thing you want the manual for. Many commands also have a --help option that will give you a list of basic options.
I should point out this isn’t Linux specific either. Many of these commands come from Unix or from other systems entirely. macOS has a similar command line system actually. It’s more that Linux users tend to use and recommend the command line more. Normally because it’s the way of doing things that works across the largest number of distributions and setups, but also because lots of technical users prefer command line anyway. Hence why people complain about Windows command lines being annoying. I say command lines because they actually have two of them for some odd reason. Anyway I hope this helped explain why things are the way they are.
In many cases that kind of answer is correct though. People ask for things that aren’t a good idea on a regular basis. Sometimes what they want is correct for their circumstances, but often not.