PHP exec() not working - Clues?

[transparencia]

Hi guys!

I have a php script that works and outputs info:

<?php
echo exec("uptime");
?>

and another that doesn't output anything:

<?php
echo exec("MP4Box");
?>

Why?

[ramin.honary]

Maybe because "MP4Box" refuses to output anything when it is executed by a non-command-line program?

Try executing this on the command line:

echo | MP4Box 2>&1 | cat

Did you get any output on the command line? The output you see from that command should be exactly the output that will be returned to the PHP script.

Otherwise, there may be some other problem, perhaps with permission -- the PHP server does not have permission to execute MP4Box, so it fails and returns no error.

But I am only guessing.