When I run this code via ssh echo wget http://domain.com/send_me_email.php | at 12:54
it ran correctly and sent me an email at that time.
Not if I run a PHP script like this
exec("echo wget http://domain.com/send_me_email.php | at 12:54");
exec("atq",$arr);
print_r($arr);
Result of that code is something like this :
job 63 at 2011-11-27 12:54
As you can see the job created successfully but I didn't receive any Email at that time?!
I test this line in php exec("wget http://domain.com/send_me_email.php");
and it sent me an email, which means that I have permission to run exec and wget via php.
I can't understand what the problem is.