How to disable a node in node editor? I have a texture node, I want to keep as it is and try another texture creating another texture node. I don't want to use the same texture node to try both.

How can disable node in node editor temporarily? In Nuke, it used to be d (for disable). Pressing d, of course, does not work in Blender. My intuition says there might be similar in Blender.
The concept of disabling in Blender is known as Muting. The shortcut is m. 

You can also right-click on a node (unlike Nuke) to pop up Node Context Menu.