PHPで空メール　実装メモ

#!/usr/bin/php -q
<?php

$source = file_get_contents("php://stdin");
if(!$source){
exit(0);
}

ereg('From: .+@[0-9a-zA-Z_\.\-]+',$source,$fromlist);
ereg('[0-9a-zA-Z_\.\-]+@[0-9a-zA-Z_\.\-]+',$fromlist[0],$from);
$to = $from[0];

参考
たぶんこの辺
http://blog.c-production.com/archives/src/mlreg.txt