Execute snippet of code when key is pressed

Question

I want to create a process in Linux which waits for some particular keys to be pressed and executes a snippet of code and goes back to sleep. How can I achieve this?

1. Initially a process will be in sleep mode
2. Wakes up when certain Keys are Pressed
3. Executes a piece of Code
4. Goes back to sleep

Additional questions

• I know I can create a daemon process for it but how can I get notification for those keystrokes?
• Do I need to create an interrupt routine for this?
• Is there a way to register a process for event notification(s) in Linux as in Android?