I am trying borisz's solutions, but as well as the others it's taking too much time to execute, so I cancelled it.. but this time the PARTIAL output I am getting is OK, I am not sure it is repeating the whole thing over and over..

Borisz's script:
#!/usr/bin/perl
use Data::Dumper;
my %products;
while (defined( $_ = <DATA> )){
  next if $. <= 2 || /^\s*$/;
  my @d   = split ' ';
  my $cat = shift @d;
  my $id  = shift @d;
  push @{$products{$cat}}, [ $id, \@d ];
}
print Dumper(\%products);
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