he says the return text for the knife as well as for any additional item(s) that are returned? if so, it's because that's what it is supposed to do.
sprintf info found here:
http://perldoc.perl.org/functions/sprintf.html
%itemcount is a hash that is populated by the server when you hand in items. the keys are item numbers, and the values are the count of that item that was turned in. things may end up changing when the inventory system is reworked.