Objective: Understand how files are organized in Unix
> On a UNIX system, everything is a file ; if something is not a file, it is a process.
>
> Machtelt Garrels
The followings are files:
- a text file
- an executable file
- a folder
- a keyboard
- a disk
- an usb key
- ...
This mean that your keyboard is represented as a file within the OS.
This file system is organized as a tree. As you have seen every folder has a parent folder exept the `/` folder whose parent is itself.
Every file can be accessed by an **absolute path** starting at the root. Your user home folder can be accessed with the path `/home/etudiant/`. Go to your user home folder.
We can also access file with a **relative path**, using the special folder "**..**". From your home folder, go to the *ubuntu* user home folder without passing by the root (we will see use of the "**.**" folder later).
