A shell script is a text file that contains a sequence of commands for a UNIX-based operating system.
It is called a shell script because it combines a sequence of commands, that would otherwise have to be typed into the keyboard one at a time,
into a single script. The shell is the operating system's command-line interface (CLI) and interpreter for the set of commands that are used to
communicate with the system
chmod u+x <script-name>chmod 777 <script-name>