#!/usr/bin/perl -w

use strict;

my @files = `find . -name "*.pl"`;
foreach my $file (@files) {

    local*FH;
    open(FH, ">$file");
    my @contents = <FH>;
    $contents[0]="#!/usr/local/bin/perl -w";
    print FH $_ foreach (@contents);
    close FH;

}