Linux Root Directories

/usr

contains application files; most of the application files used on your system are stored in a subdirectory of /usr.

/sys

contains information about the hardware in your system

/etc

contains text-based configuration files used by the system as well as services running on the system. We can edit these files with a text editor and then customize how linux behaves in different manners.

/lib

directory contains code libraries used by programs that live in /bin and /sbin

/tmp

directory contains temporary files created by you or by the system

/media

directory is used by some linux distros like OpenSUSE and Fedora to mount internal devices, including optical drives and USB drives

/home

directory that contains the subdirectories that serve as home directories for our user accounts that live on our linux system

/proc

his directory is different than the others in this list. The /proc doesn'tactually exist in the file system... instead, it's a pseudo-file system that is dynamically created whenever it is accessed. It's used to access process and other system information from the linux kernel. Within the /proc, there are several subdirectories and each of these subdirectories is identified with a number and not a name. These numbers actually correspond to Process ID numbers or (PID) number of the associated software process

/root

the /root directory is the root user's home directory - the root's home dir always lives outside the rest of the OS's user account's home dirs

/opt

this directory contains files for some programs you install on the system

/sbin

this directory contains important system management and administration files, such as fdisk, fsch, ifconfig, ifconfig, init, mkfs, shutdown, and halt.

/var

this directory contains our linux variable data, and linux log files

/srv

this directory contains subdirectories where services running on the system (like httpd for apache or even ftpd) actually save their files