This program:

#!/usr/bin/perl -w

my $a = 1;
my $b = 2;
my $c = 3;
my $d = 4;
my $e;

print "$a $b $c $d $e\n";
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Produces this output:

Use of uninitialized value in concatenation (.) or string at C:\testpe
+rl\undef.pl line 9.
1 2 3 4
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While the warning does point me in the right direction, on lines with many variables being used at once, it can take a bit of work to figure out exactly which one is undefined. Is there a way to get more explicit information from warnings like these?