This shows one of the username password combos I tried, and its result with warnings turned on:

~/bin/lowe_book/ch07 $ perl todo001.pl ellie plasma
Name "main::dummy" used only once: possible typo at todo001.pl line 36
+.
cannot validate user password
         at todo001.pl line 23.
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I have no trouble with using strict and warnings, but this is code as it appears in the text I'm studying.