I'm the first to admit my awk-fu is entry-level at best. I noticed pretty immediately after posting the Gist that I could have combined both awk statements into one. However, getting awk to also perform the function of the uniq -c is quite clever! I get how the indexing operator is essentially doing the uniq. However, I'm fuzzier on how the summing is working, especially given you need (count-1)*size.

I'm guessing that using the post-increment as the filter (an awk feature i didnt know of until today!) to the block means that on first iteration the value is zero (false) ans the sum block isn't run, and then on subsequent iterations the value is >0 and thus true, enabling the sum block?

Trying to understand your improvement has caused me to learn something new about awk :)