Sorry about that. The answer is this:
The dif_file contains two lists.
1. paths to be looked in file path_n
2. paths to be looed in file path_p
I know how to map from the list to the file and vice-veras
By reading the path data, from one huge file at a time (a few lines for each path) I can go and look it's respective list. if it is there, I should do X, continue
My idea was to convert these two lists into hashes, and to keep deleting from the hashes paths found, as It is relatively easy to genrate the key, so using exists($hash{$key}) shouldn't be that much of a problem.
That way, when the two hashes are empty, I can simply write my final output and exit, and not read the two huge files for paths that aren't needed.
Is it more easily understood now?

In reply to Re^2: huge file->hash by ISAI student
in thread huge file->hash by ISAI student

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