TL;DR
The user (default) shell and default shell (what links from /bin/sh) is two entirely different things. Just don't use '&>', but use '>/dev/null 2>&1' and you'll be fine.
As for:
exec("php test3.php &");
please go read the exec function documentation.
But you should probably move this to askubuntu.com or any other user support site. This is not a bug in PHP and I am sorry I don't think we should provide user support in the bugreports.
It's not a php-cli bug.
TL;DR
The user (default) shell and default shell (what links from /bin/sh) is two entirely different things. Just don't use '&>', but use '>/dev/null 2>&1' and you'll be fine.
As for:
exec("php test3.php &");
please go read the exec function documentation.
But you should probably move this to askubuntu.com or any other user support site. This is not a bug in PHP and I am sorry I don't think we should provide user support in the bugreports.