Of course, you should also use strict; to alert you when you get undef values.
strict doesn't warn for undef values. warnings does, for many circumstances (except when using an undefined value is perfectly fine, for example, in boolean context: undef is a perfectly fine false value) — or simply use the -w command line switch, for example in the shebang line: 
   #!/usr/local/bin/perl -w

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In reply to strict and undefined values (was: Re: Re: MD5 Peculiarities) by bart
in thread MD5 Peculiarities by skazat

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