What happens if the number has just 3 digits? 
my $test = 123;
while (length($test) < 5) {
  $test = '0' . $test;
}

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or 
my $test = 123;
$test = ('0' x (5-length($test))) . $test;

[download]
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In reply to Re: Regular Expression from Hell by Beechbone
in thread Regular Expression from Hell by Anonymous Monk

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