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

use Data::Dumper;

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

binmode STDERR, ':encoding(UTF-8)';
print STDERR Dumper(\%datatoshow);
print STDERR Dumper(\%datatoshow) =~ s/((\\+)x\{([0-9a-f]{2,})\})/
    (length($2) % 2) ? substr($2, 1) . chr hex $3 : $1/ger;

use Test::More tests => 3;

my $dumper_orig = Dumper(\%datatoshow);
my $dumper_leszekdubiel
    = $dumper_orig =~ s/\\x\{([0-9a-f]{2,})\}/chr(hex($1))/ger;
my $dumper_choroba
    = $dumper_orig =~ s/((\\+)x\{([0-9a-f]{2,})\})/
                        (length($2) % 2) ? substr($2, 1) . chr hex $3 : $1/ger;

my $VAR1;
eval $dumper_orig;
is_deeply $VAR1, \%datatoshow;

eval $dumper_leszekdubiel;
is_deeply $VAR1, \%datatoshow;

eval $dumper_choroba;
is_deeply $VAR1, \%datatoshow;