A Cheat code (also called debug code or backdoor) is a code that can be entered into a computer program to alter the run-time behavior or configuration of that program.

The code may consist of an alphanumeric string entered via a keyboard, a series of pre-defined movements of a game controller, or any of various other special input sequences initiated by the user. Cheat codes are commonly associated with video games and Live CD installation media, and are sometimes undocumented or otherwise discoverable only through easter eggs.

During Live CD initialization, a user typically may resort to using one or more cheat codes to change the booting behavior. These vary from distribution to distribution but can most often be accessed upon first boot screen by one of the function keys.

In contrast to the usage associated with video games, Live CD cheat codes are not typically associated with the concept of gaining unfair advantage or thwarting standard rules. Instead such codes are usually intended to simplify installation for different scenarios including unusual hardware configurations or special-use scenarios.