#! /usr/bin/perl
use warnings;
use strict;

use Data::Dumper;

my %mydatatoshow = (
    "\N{GREEK SMALL LETTER ALPHA}" => "\\\N{GREEK SMALL LETTER BETA}",
    '\\x{3b1}' => '\\\\x{3b2}',
);

binmode STDERR, ':encoding(UTF-8)';
print STDERR Dumper(\%mydatatoshow);
print STDERR Dumper(\%mydatatoshow) =~ s/\\x\{([0-9a-f]{2,})\}/chr(hex($1))/ger;