I'd suggest checking perlfaq6, question five. I added a solution to it, which will appear in some future Perl: 
$_ = "this is a TEsT case";
s/(test)/preserve_case($1, "success")/egi;

  sub preserve_case {
    my ($from, $to) = @_;
    my ($lf, $lt) = map length, @_;

    if ($lt < $lf) { $from = substr $from, 0, $lt }
    else { $from .= substr $to, $lf }

    return uc $to | ($from ^ uc $from);
  }

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

In reply to Re: Case-preserving regexp search and replace? by japhy
in thread Case-preserving regexp search and replace? by rrwo

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