In this chapter, we will see one of Perl's features that makes Perl one of the world's truly great programming languages hashes.[1] Although hashes are a powerful and useful feature, you may have used other powerful languages for years without ever hearing of hashes. But you'll use hashes in nearly every Perl program you'll write from now on; they're that important.
[1] In the olden days, we called these "associative arrays." But the Perl community decided in about 1995 this was too many letters to type and too many syllables to say, so we changed the name to "hashes."