#!/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);
__DATA__
Category ID Name Type Size
=======================================
WaterSports 8765 Drysuit r M-L
WaterSports 8365 Paddle t 45
WinterSports 5231 Snowboard j 85
WinterSports 5281 Gloves r S