For a tecnhique that achieves a pretty good "random" selection, with needing to read every line in the file, see Re: Approach to efficiently choose a random line from a large file.

And for a few thoughts about the randomness of such an approach see Re^2: Approach to efficiently choose a random line from a large file.

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In reply to Re: selecting N random lines from a file in one pass by BrowserUk
in thread selecting N random lines from a file in one pass by seuratt

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