The example key you give ('GMF') to show what you want to key on is perhaps too simple? What do you want to use for one of your more complicated lines like: (some spaces removed)
Iron and steel products G3311A2 3311,2
What would you be wanting to use as the key? I might imagine at least three possibilities:
- everything in those fixed columns, thus 'G3311A2 3311,2' including the spaces between the strings,
- just one part of all that, such as just 'G3311A2',
- both parts individually as alternate keys 'G3311A2' and '3311,2'
dragonchild uses $other_thingy to capture the '3311,2' separately. But what really should be done with that part?