#! perl -slw
use strict;
use Benchmark::Timer; my $T = new Benchmark::Timer;

$T->start('read');
open IN, '<', $ARGV[ 0 ] or die $!;
my $text;
sysread IN, $text, -s( $ARGV[ 0 ] ) or die $!;
$T->stop('read');
printf "file contains %d bytes\n", length $text;

my $count = 0;
$T->start('regex');
$count++ while $text =~ m[(12345)]g;
$T->stop('regex');
print "$count matches found";

$T->report;

__END__
C:\test>junk junk.dat
file contains 213909504 bytes
2016 matches found
1 trial of read (452.624ms total)

1 trial of regex (260.872ms total)