use strict;

my $ident="aaa bbb ccc-ddd eee fff-ggg hhh iii-jjj kkk lll-";

my @id = split /-|\s/, $ident;
foreach my $i(0..$#id) {
    print $id[$i];
    if ((($i+1) % 3) == 0) {
        print "\n";
    } else {
        print ' ';
    }
}