In response to webmaster at spectreanime dot com:
"For some obscur reasons, just after ur command, u need to make a sleep to be sure, that the command has reached the server and is running"
Actually what you must do is set the blocking of the string to true, so it waits until the server sends data to the STDOUT before echoing it.
So, instead of:
sleep(1);
Just do:
stream_set_blocking($stdio, true);
Best regards,