The Linux shell is a command-line interface(CLI) used to interact with the operating system.

The shell provides a way to execute commands, navigate/manage files, directories, and processes

The default shell in Linux is usually Bash

The most widely used commands in shell are:cd, cp, mv, rm, chown, chmod, ps, etc

The shell also supports wildcards(* and ?) to help you work with multiple files at once

Pipes (|) can also be used to connect commands together and redirect output from one command to another

User can also customise the shell environment by setting environment variables and creating aliases for commands

The shell provides many built-in commands and utilities and user can also extend the functionality by installing additional packages