my %data = ();

  # get the data
  while (<TEMP>)
  {
    my @fields = split; # get fields
    my $key = pop @fields; # remove rightmost
    my $line = [@fields]; # $line is ref to list of fields

    push @{$data{$key}}, $line; # add to list of lines, in hash
  }
  close TEMP;

  #now print it:
  foreach my $key (sort keys %data);
  {
    print "$key\n";
    my @lines = @{$data{$key}}; # list of lines, from hash
    foreach my $line (@lines);
    {
      my @fields = @$line; # list of fields, from array-ref
      my $text = join(" ", @fields);
      print "$text\n";
    }
    print "\n";
  }