I am attempting to parse a large file (~10 GB) but having issues with running out of system memory to do so. I start out with about 3.5 GB used and end up using all 16 GB before Linux kills the process.

Here is the code that is failing for me:

#!/usr/bin/perl

use strict;
use warnings;
$| = 1;

open(my $readHandle, '<', "File.txt") or die "Failed\n";

print "Start Read\n";

foreach my $line (<$readHandle>) {

    print "Read Line\n";
    print "Found!\n" if ($line =~ /MatchingText/);
}
        
close $readHandle;
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When I run this program, "Start Read" is printed to the screen, but I never see "Read Line".

I've done a bunch of Googling on this, and found a bunch of hits, but everything I read says to just read the file one line at a time to get around the size. But isn't that what I'm already doing??? All the specific examples I see for fixing the issue focus on other things the user is also doing which are also taking up memory.