PHP exec操作不运行我的电子邮件脚本的最新版本

I'm doing something really simple, and getting some unintended results. I'm running a simple exec operation in my php script (called emailsetup.php), and it's running a simple php script that writes an email (called email.php). It's sending the email, but when I modify my email php script, it always sends the original email text from yesterday.

I've tried a bunch of different iterations on the exec command, but all of them send the first version of my email. When I edit the subject string and save email.php, then run the emailsetup.php script in my browser, it always sends the original email. It's confounding, because I haven't used that version of the email strings in hours.

The codes are really simple: (emailsetup.php)

 <?php
 exec('echo "email 2>&1" | at now + 1 minute');

and (email.php)

<?php
    $to      = 'me@myemail.com';
    $subject = '[Testing 06]';
    $message = 'Message testing 06';
    $headers = 'From: my2@myemail.com' . "
" .
    'Reply-To: my2@myemail.com' . "
" .
    'X-Mailer: PHP/' . phpversion();
    if(mail($to, $subject, $message, $headers)) {
        echo 'Email successfully sent [test 6]';
    }
?> 

When I run the php file in my browser, it echoes the latest number (in this case 6), but when I check my emails, they always show the "test 1" subject and body. So the exec is finding the latest up-to-date email.php file. But the email is not sending properly. How can I get the operation to forget the older versions?