my $v = "FD02:3539:700B:1::FE";
 
 #way 1
 if ( $v =~ /^([0-9A-F]{4}):([0-9A-F]{4}):([0-9A-F]{4}):([0-9A-F]{1})::([0-9A-F]{2})/ )
 {
    print "$1 - $2 - $3 - $4 - $5\n";
 }
 
 #way 2
 my @v = split /::?/, $v;
 print join (" + ", @v), "\n";