It would help to know what the error is on the open. Check for that, and print a message if it fails, like so: 

open(IN, "<$in_file")
    or die "Can't open $in_file: $!\n";

[download]
Clearly the file isn't open by the time you try to read it, so start by figuring that one out first.

In reply to Re: Parsing a 3 - 4 gig text file by VSarkiss
in thread Parsing a 3 - 4 gig text file by Anonymous Monk

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