Start background processes from a background process

I have a PHP script say test.php in linux Ubuntu, in this PHP script I use shell_exec() to start several background processes.

When I execute php test.php, the background processes are started as expected, but when I run php test.php &, those several background processes are not started.

Is it not a supported way to start background processes from a background process, or is there a better to go about this?

Answer

Try php test.php < /dev/null & – some Unix distributions seem to expect some input and send the process idle to background. Tested on Fedora Linux (bash) you can start php test.php & but it isn’t executed. Check with jobs running background process – catch from background and execute with fg.