- /usr/X11R6 - The files managing your X Window Server (this is the base on which all the different Linux desktops are built. If you use a graphical desktop of any kind in Linux, this is what it runs on).
- /usr/bin - Commands that aren't essential for users, but are useful.
- /usr/games - Pretty self-explanatory! Games you install on your system, except for those you put in /opt.
- /usr/include - The files that the C programming language (used to write the Linux kernel and most of the programs it needs to run) needs to work.
- /usr/lib - Shared code used by many programs in the /usr directory.
- /usr/local - Programs and other items you want to keep locally.
- /usr/sbin - Commands that aren't essential for administrators but are useful.
- /usr/share - Information you can use on any Linux machine (even if it's running completely different hardware from what his one is running)
- /usr/src - Source code used to build software on your system
So that brings to an end our tour of the Linux filesystem. Don't worry too much if little of it makes sense, you just need a general idea of what's kept where. With practice, you'll soon learn where everything is!