From SMTheming Wiki
Commands are how things get done in the theming world. Without them, you can't really do anything but change graphics, and a number of people have already done that with mixed results.
|StepMania 3.9 and 5.0|
|Differences between 3.9 and 5.0|
|StepMania 3.9 only|
|StepMania 5.0 only|
GameCommands affect gameplay and other aspects of the program, rather than graphics.
Overview: Other commands
Certain builds of StepMania 4 can export Lua information, which includes all of the commands at your disposal (both built into StepMania and augmented with Lua scripts). KKI Labs hosts an online copy of the SM Lua documentation for various versions:
These links are provided for reference only, as these versions of StepMania are no longer maintained.