A PNACH file is a cheat code file used by PCSX2, a game emulator for PlayStation 2 games. it contains data that enables GameShark or Code Breaker codes, or other types of cheats. PNACH files include the game title, version of the game (e.g., SLUS), and the cheat code.

PNACH files are saved in a plain text format and can be edited with any text editor. However, you may need to rename the ".pnach" extension to ".txt" to open the file, then rename the extension back to ".pnach". The cheat code is a hexadecimal code that is used by the emulator to insert modified data into the emulated game at a particular data point. Here are the contents of an example PNACH file: gametitle=My Game [SLUS 12345] (U) comment=A comment patch=1,EE,0032C220,word,000000FF The PNACH filename prefix must use the CRC code given to the PlayStation game. It also must be stored in the \patches\ directory of the PCSX2 installation. PCSX2 automatically loads PNACH files that have a CRC code that matches the game CRC code. NOTE: The term "pnach" is pronounced "patch."