#!/usr/bin/perl 
use POSIX qw(strftime);
my $mon = strftime("%b",localtime(time()-86400));
my $day = strftime("%d",localtime(time()-86400));
my $yesterday  = strftime("%Y%m%d",localtime(time()-86400));
my %success;
my %all;
my $dom  = shift || "";
my @f = </var/log/maillog*>;
my $last_file = (map { $_->[1] } sort { $b->[0] <=> $a->[0] } map  { [ (stat($_))[9], $_ ] } @f)[0];
my $pat_one = qr/$mon/s+$day.*?to=<(.*?/@(?:[^.]+/.)*$dom[^>]*)>.*?status=sent/x;
my $pat_two = qr{$mon/s+$day.*?to=<(.*?/@(?:[^.]+/.)*$dom[^>]*)>.*?}x;

open LOG,$last_file;
while(<LOG>) {
  if (/$pat_one/) {
    $success{$1}++;
  }
  if (/$pat_two/) {
    $all{$1}++;
  }
}
close LOG;

最后对 %success,%all操作，可以写到文本，可以记录到数据库等等

运行： xxx.pl domain_name   
例如：a.pl sohu.com