Where can i install RTLinux? Or how can i install RTLinux?
 

I installed RTLinux. Can anyone tell how the GUI of RTLinux looks like? Is it just like a command prompt? Then which command can be used to type d programs?

I think you are referring to the WindRiver RTOS that runs Linux over the top of a real-time core system. It can be downloaded from their website.

This is distinct from the Linux kernel with real-time patches.