[js2]

I use Node.js a lot for scripting like this. It's much easier and a more powerful alternative to bash scripts.

I'll use node for Unix scripting when you pry every other alternative from my cold dead hands:

  awk '{a[$2] += $3};END{for(x in a){print x, a[x]}}' sample.txt 
  A 2
  B 14
  C 6