Creating a Bash Script
Let’s start by creating a new file with a .sh extension. As an example, we could create a file called devdojo.sh.
To create that file, you can use the touch command: touch devdojo.sh
Or you can use your text editor instead: nano devdojo.sh
In order to execute/run a bash script file with the bash shell interpreter, the first line of a script file must indicate the absolute path to the bash executable: #!/bin/bash
This is also called a Shebang.
All that the shebang does is to instruct the operating system to run the script with the /bin/bash executable.
Derived from: https://github.com/bobbyiliev/introduction-to-bash-scripting