Team,

I have two large files, about 16 million records each.
The files are sorted.
The first 13 characters are used as a key.
We get an updated file every week.
We also keep the previous week file.

I need to compare the keys from the new file to the keys on the file from
last week. If the rest of the records are the same, then I do nothing. If
the keys matches but the rest of the records are different, I then have an
update and I will output that record to a new file.
I was wondering if there is an efficient way to do this in Ruby. Either any
built-in method or an efficient algorithm which I can implement.

Thank you


-- 
Ruby Student