Rather than read $LARGEFILE once for each line in $REFFILELIST, wouldn't it be more efficient to read it once and check each line against each line of $REFFILELIST?

Something like:

open (FILE, $ReferenceFilePath) or die "Can't open file";
chomp (@REFFILELIST = (<FILE>));
close(FILE);

open OUTFILE, ">$OUTPUTFILE" or die $!;

open (LARGEFILE, $LARGESIZEDFILE) or die "Can't open File";
while (<LARGEFILE>) { 
    foreach my $line (@REFFILELIST)   {        
          print OUTFILE $_ if (index($_, $line);
     }
}
close(LARGEFILE);
close(OUTFILE);

[download]

N.B. untested since the original is incomplete and doesn't provide any data.

In reply to Re: Out of Memory Error : V-Lookup on Large Sized TEXT File by thargas
in thread Out of Memory Error : V-Lookup on Large Sized TEXT File by TheFarsicle

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