The Filesystem Hierarchy Standard defines the structure of file systems on Linux operating systems. 

/ – The Root Directory :: Everything on your Linux system is located under the / directory, known as the root directory.

/bin – Essential User Binaries :: The /bin directory contains the essential user binaries (programs) that must be present when the system is mounted 

in single-user mode.

/boot – Static Boot Files :: it contains the files needed to boot the system – for example, the GRUB boot loader’s files and your Linux kernels are 

stored here.

/dev – Device Files :: Linux exposes devices as files, and the /dev directory contains a number of special files that represent devices. 

/etc – Configuration Files :: The /etc directory contains configuration files, which can generally be edited by hand in a text editor. Note that the /etc/ 

directory contains system-wide configuration files – user-specific configuration files are located in each user’s home directory

/home – Home Folders :: it contains a home folder for each user.

/lib – Essential Shared Libraries :: it contains libraries needed by the essential binaries in the /bin and /sbin folder. Libraries needed by the binaries 

in the /usr/bin folder are located in /usr/lib.

/lost+found – Recovered Files :: Each Linux file system has a lost+found directory. If the file system crashes, a file system check will be performed at 

next boot. Any corrupted files found will be placed in the lost+found directory, so you can attempt to recover as much data as possible.

/media – Removable Media :: it contains subdirectories where removable media devices inserted into the computer are mounted. For example, when 

you insert a CD into your Linux system, a directory will automatically be created inside the /media directory.

/mnt – Temporary Mount Points :: it is where system administrators mounted temporary file systems while using them.

/opt – Optional Packages :: directory contains subdirectories for optional software packages. 

/proc – Kernel & Process Files :: it is similar to the /dev directory because it doesn’t contain standard files. It contains special files that represent 

system and process information.

/root – Root Home Directory :: it is the home directory of the root user. Instead of being located at /home/root, it’s located at /root. This is distinct 

from /, which is the system root directory.

/run – Application State Files :: it is fairly new, and gives applications a standard place to store transient files they require like sockets and process 

IDs. These files can’t be stored in /tmp because files in /tmp may be deleted.

/sbin – System Administration Binaries :: it contains essential binaries that are generally intended to be run by the root user for system 

administration.

/srv – Service Data :: it contains data for services provided by the system.

/tmp – Temporary Files :: Applications store temporary files in the /tmp directory. These files are generally deleted whenever your system is restarted 

and may be deleted at any time by utilities such as tmpwatch.

/usr – User Binaries & Read-Only Data :: it contains applications and files used by users, as opposed to applications and files used by the system. 

/var – Variable Data Files :: it is the writable counterpart to the /usr directory, which must be read-only in normal operation. Log files and everything 

else that would normally be written to /usr during normal operation are written to the /var directory. For example, you’ll find log files in /var/log