#/usr/bin/perl
use strct;
use warnings;

my $chuncksize=10*1024*1024; # 10MB je größer je schneller
my $file='C:\myfile.txt';
my $regexp=qx/CP_NG/o;

open(TRACEFILE, '<',  $file ) or die "cannot open $file $!\n";

my $found=0;
my $chunk;

while (read(TRACEFILE, $chunk, $chuncksize))
{
  $found += $chunk =~ m/$regexp/g;
}
print "anzahl treffer: $found\n";