Definitive website or pdf that explains about linux?

like what is X windows,Cygwin,file system

From stackoverflow

• I think this is a great way to start

• Well, first you have to choose which Linux distribution you wish to use/learn, then you just use that distro's documentation, which normally has allot info.

  You can find here some linux beginner lessons: http://www.linux.org/lessons/beginner/toc.html

  Finally the best way to learn, besides reading is "getting your hands dirty". Install a distro of your choice and mess with it :)

  Rich : Getting my hands dirty is definitely how I learned - you install it, fiddle, wonder how to do something, search, and learn :)