1. I'd check if you are exhausting your available RAM
  2. I'd use split
  3. I'd build a hash keyed by sorted pairs and skip regex/index entirely
  4. If not enough RAM, I'd process the first file $N lines at-a-time

- tye        

In reply to Re: how to speed up pattern match between two files (hash) by tye
in thread how to speed up pattern match between two files by Anonymous Monk

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