A few days ago I upgraded from the Centos 5 CR repository software including Apache. The Apache on my development server is: Apache/2.2.3 Aug 31 2011 20:18:21 httpd.x86_64 0:2.2.3-53.el5.centos.1 A previously working PHP Exec(...) command on a web page no longer works. After spending 7+ hours Googling, checking file and directory permissions, whether SELinux is on or off and doing numerous tests my once very nice routine will not work because the Shell processing by Apache seems to have altered. The consistent error message always includes: No such file or directory or command not found I have downgraded to httpd.x86_64 0:2.2.3-45.el5.centos.1 and restarted httpd but the problem persists. It appears to me, the PHP EXEC command is being executed in a 'black hole' with no access to the directory structure and that is why the weird error message occur. Helpful comments appreciated. Paul.