As a Linux user, I'd ask how to learn the Linux's directories and files, since everything in Linux is a file descriptor.
I've worked with some distribution of Linux so I think I did understand commands enough.I don't know this is true or not,but I believe the kinds of commands which configure the system work with files,so understanding Linux's files may be a good point to make a firm understanding of it.
By the way,Would you mind guiding me ?