I'm always looking for sources like these, but I can never find a place that let's me just look at file 1 and move on from there. If anyone's got any resources

I'm always looking for sources like these, but I can never find a place that let's me just look at file 1 and move on from there. If anyone's got any resources that might give me an idea of the file progression – from OS to OS with teeth – I'd be extremely obliged. I'd like to grok *nix.