While debugging some code that's printing "HASH(0x9999999)" to stdout

ikegami and LanX have given you some excellent answers. I am wondering why you don't just change the code you're debugging to use Data::Dumper or Data::Dump to show you the hashes? Even if you don't have full control over the code, Perl provides lots of ways to monkey-patch stuff in. If you could show some of the code that is generating this debug output, perhaps we could suggest a way to do that.