You definitely can. For example I know x86. I can read it and understand it quite well. But if you asked me to write even a basic program in it, it would take

You definitely can. For example I know x86. I can read it and understand it quite well. But if you asked me to write even a basic program in it, it would take me a considerable amount of time. The same goes with shell scripting. But more importantly you don’t have to understand code to the same degree and depth. When I read code I understand what the code is doing and if it looks correct. I’m not going over other design decisions or implementation strategies (unless they’re obvious). If I did that then I’d agree. Id also stop doing code reviews and just write everything myself.