That's broken, due to the use of the string comparison operators (like lt) in the place of numerical comparison operators (like <). Also, a while loop can be replaced with math:

$string = ('0' x ($wanted - $current)) . $string;
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But honestly, this is a job for sprintf():

sprintf "%0${len}d", $number;
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That is, sprintf("%05d", 123) returns 00123.

_____________________________________________________
Jeff[japhy]Pinyan: Perl, regex, and perl hacker.
s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;