Finding/changing config files though Ubuntu

Hi There,

I have to change "/etc/php.ini" in my Ubuntu 14.0.4. to "extension_dir = /etc/php.d.

Tried to do it, but I get an error saying no such a file...

and also need to activate MySQL extension via /etc/php.d/mysql.ini

";Enable my sql extension module
extension=mysql.so"

But I don't find this directory in my Ubuntu install except for "apache2, cgi, cli , mods-available"

I would appreciate your help.

Thanks, Pipa.