This book is not about good scripting design techniques, but good reusable code. You do not have to make the script complicated when it can achieve the same results through solid understandable code. If I wrote a book that way, I might impress you, but it would take a lot longer for you to get to grips with the code. This is not my goal; my code works and it works using basic scripting techniques, which you will learn more quickly. You will then be able to impress your friends more quickly!
A script is not a compiled program: it is interpreted, line by line. The first line of the script should always start with
This lets the shell know where the Bourne shell interpreter is to be found on the system.