Responsive Design is a new trend in Web Design. It was started by Ethan Marcotte. Responsive Design is the design of websites that work well when viewed on a wide range of devices. For example a responsive website will look good on Iphone, Ipad, Tablets, Laptops and Desktops.
The top command can be used in combination with bash tools to find CPU usage. The article: Finding CPU usage from top command describes how to find CPU usage using the top command.
The RAM on a server can be monitored using /proc/meminfo and awk commands. /proc/ is a special file system created by the Linux kernel which contains kernel related information such as CPU and memory usage. /proc/meminfo contains information about memory usage.
To allow Apache web server, to process files ending with .html as PHP files, we need to do two things. First we need to set the content-type http header for .html files to text/html. Secondly, we need to tell the Apache web server to process HTML files as PHP files.