Shell scripts allow several commands that would be entered manually at a command-line interface to be executed automatically, and without having to wait for a user to trigger each stage of the sequence. Shell script is a program designed to be run by the Unix/ Linux shell
This course cover Unix command and shell scripts include file manipulation, program execution, and printing text. A script which sets up the environment, runs the program, and does any necessary cleanup, logging etc
term is also used more generally to mean the automated mode of running an operating system shell; in specific operating systems they are called other things such as batch files
A shell script can provide a convenient variation of a system command where special environment settings, command options, or post-processing apply automatically, but in a way that allows the new script to still act as a fully normal Unix command.