use IO::String;
my $io = IO::String->new;
# Serialize Key Value
foreach my $k( keys %ENV){
    my $v = $ENV{$k};
    $io->print( pack("NN", length $k, length $v).$k.$v );
}

# wiederherstellen
$io->seek(0,0);
my %env = ();
while( read($io, my $buffer, 8) ){
    my ($klen, $vlen) = unpack "NN", $buffer;
    read($io, my $key, $klen);
    read($io, my $val, $vlen);
    $env{$key} = $val;
}

print Dumper \%env;