I have been looking the shader files using normal notepad already. But the main problem is that I have verry litle knowledge about shaders.

The main reason why I'm looking for ready shader editor program is becouse I would like to try converting some Level 4 pixel and vertex shaders into Level 3 pixel/vertex shaders. Why would I like to do this? I have recently bought alpha version of game Maia (http://maiagame.com/) which uses Level 4 shaders but my hardware only supports Level 3 shaders.
So I would hate to see that I threw 18€ for a game I can't play.
Yes I could ask developers to also write Level 3 shaders for their game but that won't happen soon as they have more work on other aspects of their game.