su command not working, eventhough I am rooted
My device is a rooted Motorola Razr HD smartphone (also known as XT925) currently running Android 4.4.2 (stock ROM) with the Terminal Emulator app installed. In my case, all I have to do is to start Terminal Emulator and then execute this command:

su -


This causes me to become root and thus be able to execute any other command I want.