use Data::Dumper;
my %h = (
    foo => 1,
    bar => {
        quux => 2,
        frob => 3,
    },
);
open my $fh, '>', 'hash.pl' or die "nope: $!";
print $fh Dumper(\%h);
close $fh or die "fasten seat belts. Last orders: $!";