what is linear stepper motor and rotary stepper motor? any details or description for these?

A stepper motoris a motor that uses two or more electromagnetic pole assemblies with teeth on them such the teeth are are off set so you can get very precise movements base on which poles are energized.

There are two both linear and rotary steppers. Linear stepper motors are laid out in a linear configuration. Rotary steppers are similar to a conventional motor.