gistfile1.txt

I have a nested set of hashes like:

[A]
  [B]
  [C]
    [D]
    [E]
  [F]
[A']
  [B']
  [C']
    [D']
    [E']
  [F']
[A'']
  [B'']
  [C'']
    [D'']
    [E'']
  [F'']
  
I want to get an array like:

[A,A',A'']
[B,B',B'']
[C,C',C'']
[D,D',D'']