programming-examples/perl/Hash/Keys function is used to get all keys in a hash.pl

#!/usr/bin/perl -w

use strict;

my %where = (
     G     => "Dallas",
     L     => "Exeter",
     I     => "Reading",
     S     => "Oregon"
);

foreach (keys %where) {
    print "$_ lives in $where{$_}\n";
}