The Data::Dumper module on CPAN (or the 5.005 release of Perl) is great for printing out data structures. The Storable module, found on CPAN, provides a function called dclone that recursively copies its argument.
use Storable qw(dclone);
$r2 = dclone($r1);Where $r1 can be a reference to any kind of data structure you'd like.
It will be deeply copied. Because dclone takes and returns references,
you'd have to add extra punctuation if you had a hash of arrays that
you wanted to copy.
%newhash = %{ dclone(\%oldhash) };