Specifies a file to record all input from a system session. This can be used to record a game session for later playback. This feature does not work reliably for all systems, but can be used to watch a previously recorded system session from start to finish. In order to make things consistent, you should only record and playback with all configuration (.cfg), NVRAM (.nv), and memory card files deleted.

The default is NULL (no recording).

mess -record <filename>