use Data::Dumper;
my $complexVar = { a => 1, b => [2,3,4], c => 5 };
unless (open FH, ">$file")) {
  die "Error in opening '$file' for writing: $!\n";
}
print FH Dumper($complexVar);
close (FH);
undef($complexVar); # weg issi

my $complexVar2 = &ReadDump($file);
sub ReadDump {
  my $file = shift;
  local $/; # undef, alles auf einmal einlesen
  open (FH, $file) or die "Error in reading '$file': $!\n";
  my $string = <FH>;
  close (FH);
  my $var = eval $string;
  return $var;
} # ReadDump