I second Abigail's suggestion. To reiterate -- first sort, then do the comparison.

A while back I was twiddling around during some "downtime" and I cooked up the following little Perl exercise. Remove duplicate email addresses from a file where each line was an address. So, I applied the usual, build an array, sort, take out the unique addresses, write them to a new file. Took just under 2 mins on my fast Windows box at work, and about 3.5 mins on my relatively pokey iBook at home. Both machines had half Gb ram.

The file was 300+ Mb in size and had about 145 million rows in it.

;-)

In reply to Re: Re: How to process two files of over a million lines for changes by punkish
in thread How to process two files of over a million lines for changes by richard5mith

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