You can open the file without having all (however many) GB's read into memory. Opening the file just gives you access to it; what you do from that point is up to you. You can read in a file line by line this way: 
open FOO, "<my_hug_file.dat";
while (<FOO>) { # reads one line of the file into $_
   # do something
}
close FOO;

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In reply to Re: How to work on a large Data file line by line by Anonymous Monk
in thread How to work on a large Data file line by line by Anonymous Monk

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