Re^3: Annoying 'Use of uninitialized value in concatenation' warning

If you use diagnostics perl will tell you which category the warning belongs to. For example, printing an uninitialised variable yields (the category is in bold):

Use of uninitialized value $x in print at
/home/bri/foo.pl line 14 (#1)
(W uninitialized) An undefined value was used as if it were already
defined. It was interpreted as a "" or a 0, but maybe it was a mistake.
To suppress this warning assign a defined value to your variables.

Additionally, perldiag lists all of perl's warning and error messages.

Perl: perlintro    perlretut    perldoc    Basic debugging checklist    Yes, even you can use CPAN
PerlMonks: How do I post a question effectively?    Markup in the Monastery    How do I post a question effectively?    I know what I mean. Why don't you?
General: How To Ask Questions The Smart Way    What every computer scientist should know about floating-point arithmetic
To Be Continued...

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