The log file is large, it sometimes gets up to 3GB

A large file seeking technique is described here and it works very well.. the discussion was about replacing characters with  tr, you can adapt it to your IP matching needs easily I think. HTH

In reply to Re: Efficient Way to Parse a Large Log File with a Large Regex by hsinclai
in thread Efficient Way to Parse a Large Log File with a Large Regex by Dru

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