#!/usr/bin/perl

use strict;
use warnings;
my $bytes;

open(FILE, "squid.log") or die $!;

while(<FILE>) {
   next unless m/\d+\s\d+\s\d+.\d+.\d+.\d+\s\w+\/\d+\s(\d+)\s\w+\s(.*?)\s(?!-)\w+\s\w+\/(?!172.\d+.\d+.\d+)/;
   #1257981327.964 212098 172.16.32.142 TCP_MISS/200 3037 CONNECT mail.google.com:443 rgabriel DIRECT/172.16.32.14 -
   $bytes += $1;
}

close(FILE);

print "$bytes\n";