It definitely can run two steppers or 4 DC Motors maybe this link will explain more
Thanks for your help much appreciated
Also i just seen in the link above this command sounds like it can follow another motor I'm wondering if I can map encoder to run a fake motor on Arduino and copy that action too motor shield maybe a long shot .
uint8_t onestep(uint8_t dir, uint8_t style);
The oneStep() function is a low-level internal function called by step(). But it can be useful to call on its own to implement more advanced functions such as acceleration or coordinating simultaneous movement of multiple stepper motors. The direction and style parameters are the same as for step(), but onestep() steps exactly once.