Hi,
I feel that your worry is about 25000 lines of data into hash or into perl's memory!.
If my guess is correct, you can use DBM::Deep. But since the data will be stored in a file, it will not be as quick as normal hash.

In reply to Re^3: comparing two files, with known variations by targetsmart
in thread comparing two files, with known variations by sathiya.sw

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