Files considered harmful?!
In his rant about files, Liam has missed a fundamental difference between old desktop computers like a C64 and anything modern - or for that matter between a C64 and any commercial computer at the time. The reason you could just use line numbers like that is because your C64 could only run one program at a time. Multitasking of any form was impossible. Multi-user sessions of any form were impossible. As soon as you wanted to do anything more useful, you needed to abandon that idea - which is why AmigaBASIC and other later BASICs didn't use line numbers and did use files. It's also why every language developed on larger machines - C for a prime example - used files with human-readable text from day one.
Line numbers also directly encouraged spaghetti code and directly discouraged structured programming. Sure you could do structured programming if you knew those structures, but it wasn't anything like common.