Learn Linux Shell Scripting - Fundamentals of Bash 4.4

Checking arguments

As we noted in the previous chapter, when you're dealing with positional arguments passed to your script, a few things are very important. One of them is whitespace, which signifies the boundary between arguments. If we need to pass an argument to our script that contains whitespace, we need to wrap that argument in single or double quotes, otherwise it will be interpreted as multiple arguments. Another important aspect of positional arguments is getting exactly the right number of arguments: not too few, but definitely not too many either.

By starting our scripts (that use positional arguments) with a check on the number of arguments passed, we can validate if the user called the script correctly. Otherwise, we can instruct ...