sub mac2long {
  my @mac = unpack("A4"x3,shift);
  my $long = 0;
  foreach my $octet (@mac) {
    $long <<= 16;
    $long |= hex($octet);
  }
  $long;
}

sub long2mac {
  my $long = shift;
  my @octets;
  for (my $i = 2; $i >= 0; $i--) {
    $octets[$i] = sprintf("%04x",($long & 0xFFFF));
    $long >>= 16;
  }
  join('.',@octets);
}
chomp(my $inmac = shift @ARGV);
my $long = mac2long($inmac);
print "$inmac converted to long: $long\n";
my $outmac = long2mac($long);
print "$long converted to mac: $outmac\n";

##</code><code>##

001095123456 converted to long: 2500998230
2500998230 converted to mac: 0000.9512.3456