Shell is an interpreter which converts scripts or executables to machine action. Shell prompt is a Command-line interface as well as GUI (Graphical User Interface) that takes inputs from the user and executes selected program according to that. Shell Scripts can be combined in a package for automation and schedule background tasks. Shell Scripts will be saved using extension .sh and scheduled using corn jobs. Some majorly known shells as below: sh: sh is known as Bourne Shell (sh). This is the original UNIX shell which has limited functionality. Command path is located at /bin/sh and /sbin/sh. bash: Default shell in most Linux installations and compatible with the legacy sh shell. bash is the short name of Bourne Again Shell. Command path is /bin/bash. ksh: High-level programming language shell known as Korn Shell. Command path is /bin/ksh. Tcsh/csh: Tcsh or csh is also known as C Shell. This works on C language syntax. Command path is / bin/csh.