Full description
sdl-jstest and sdl2-jstest are simple programs that lets you find
out how many joysticks SDL or SDL2 detected on your system, how many
axes, buttons, hats and balls they have each. They also lets you test
the joysticks by displaying the events they send or by displaying
their current button, axis, hat or ball state. sdl-jstest is
especially useful if you want to test your SDL_LINUX_JOYSTICK
configuration.