what is shell in linux

In Linux, the shell is a program that provides an interface between the user and the kernel and executes programs called commands. It is a command language interpreter that executes commands read from input devices such as the keyboard and converts them into something which the kernel can understand. The shell is both an interactive command language and a scripting language, and is used by the operating system to control the execution of the system using shell scripts. There are different flavors of a shell, just as there are different flavors of operating systems. The most commonly used shell program in Linux is bash, which stands for Bourne Again SHell, an enhanced version of the original Unix shell program, sh, written by Steve Bourne.