If key and have fixed length (for example both 32 bit integers), you could write it into a binary and do a binary search.

I think there is also a small unix tool that does line based binary search in files, but I can't remember the name. Update: It seems look (1) (in Debian shipped with in the bsdmainutils package) does the trick, but I'm not sure if it works with numerically sorted lines.

In reply to Re: fast lookups in files by moritz
in thread fast lookups in files by citromatik

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