#!/usr/bin/env perl 
use strict;
use warnings;
use Test::More;

my $instr = "a\xe9b\xe9";
my $outstr = replace ($instr, "\xe9", "\x65");
is ($outstr, 'aebe');
done_testing;

sub replace {
    my ($in, $find, $replace) = @_;
    $in =~ s/$find/$replace/g;
    return $in;
}