When we login into our user account on Linux, we are placed into our home directory inside a shell. Our home directory is a subdirectory of the /home directory. At the very top level of Linux filesystem, there is the root directory, which is represented by the / symbol. You can relate this to C: in Windows. However on Windows we can have many drive letters that all have their own root levels, such as C:, D:, E:, and so on.

In Linux, there is only one root directory /. All other directories are subdirectories of the root directory. The following table gives a brief overview of files and the information contained in each directory.

Directory	Description
/	The root filesystem only contains other directories but no individual files.
/bin	The binaries directory contains executable files. Points to /usr/bin.
/dev	The device directory contains device files of users and services.
/etc	Contains system configuration files for users and services.
/home	User's home directories
/lib	System libraries files. Points to /usr/lib
/media	Directory for mounting media such such as USB drivers or DVD disks.
/mnt	The mount directory for mounting remote filesystems.
/opt	Directory in which third-party software is installed
/proc	A virtual filesystem that tracks system processes.
/root	The root user's home directory
/run	Variable and volatile run-time data.
/sbin	System binary (executable) files.
/srv	Might contain data from system services.
/sys	Contains kernel information.
/tmp	Temporary file directory for session information and temporary file storage.
/usr	Programs and libraries for users and user-related programs.
/var	Variable files such as logs, spools, and queues.

For the note, system files are protected from user modification. Only the root (administrative) user can modify system configuration files and settings. Users generally only have write access to their own home directories, the /tmp directory, and shared directories specifically created and modified by the administrator.