Let's look at a few simple examples of creating and using references so you can get a feel for the technique. Perl actually has a number of ways of working with references, but here we'll focus on the easiest and most popular mechanisms, and explore the others in a later section (“Other Ways of Using References”).
Start with something you've seen a gazillion times before in this book: A plain old scalar variable that contains a string.
$str = "This is a string."
This is an ordinary scalar variable, holding ordinary scalar data. There's some location in memory that stores that string, which you can get to through the $str variable name. If you assigned something else ...