/ Root directory—the starting point of the directory tree.
/bin Essential binary files, such as commands that are needed by both the system administrator and normal users. Usually also contains the shells, such as Bash.
/boot Static files of the boot loader.
/dev Files needed to access host-specific devices.
/etc Host-specific system configuration files.
/home Holds the home directories of all users who have accounts on the system.
However, root’s home directory is not located in /home but in /root.
/lib Essential shared libraries and kernel modules.
/media Mount points for removable media.
/mnt Mount point for temporarily mounting a file system.
/opt Add-on application software packages.
/root Home directory for the superuser root.
/sbin Essential system binaries and commands that are needed by system administrator.
/tmp Temporary files.
/usr Secondary hierarchy with read-only data.
/var Variable data such as log files.