I was trying to figure out a good way to break the key search into ranges.
I decided to use columns, ie. 17 columns. And group them into 4.

group 1  2000 - 2fff
group 2  0000 - ffff
group 3  0000 - ffff
group 4  0000 - ffff
group 5  0123456789abcdef

output:    group 1 has 4096 lines
      group 2 has 65536 lines
      group 3 has 65536 lines
      group 4 has 65536 lines
      group 5 is 16 lines.
         
My idea is to create 2000 0000 0000 0000 0
But I'm still not sure how to bring them together in a string.