Every directory on a Unix system (and probably every other system too) contains at least two directory entries. These are . (current directory) and .. (parent directory). In the case of the root directory, these point to the same place, but with any other directory, they are different. You can see this for yourself using the stat, pwd and cd commands (on Linux): $ cd / $ stat . .. bin sbin ...
directory - What are ./ and ../ directories? - Unix & Linux Stack Exchange
windows - What are "." and ".." in a directory? - Super User
Check "The folder metaphor" section at Wikipedia. It states: There is a difference between a directory, which is a file system concept, and the graphical user interface metaphor that is used to represent it (a folder). For example, Microsoft Windows uses the concept of special folders to help present the contents of the computer to the user in a fairly consistent way that frees the user from ...
In Unix, a directory just contains names and references to filesystem objects (inodes, which can refer to directories, files, or some other exotic things). A file can appear under several names in the same directory, or be listed in several directories. So "space used by the directory and the files inside" really makes no sense, as the files aren't "inside". That said, the command du(1) lists ...
What is the location of the $HOME directory in Windows (WSL v2)? i.e. What address can I type in Windows Explorer to get to the $HOME directory in my WSL installation. ...