To follow the trail of.
To follow the history of.
To draw or sketch lightly or with care.
He carefully traced the outlines of the old building before him.
To copy onto a sheet of paper superimposed over the original, by drawing over its lines.
To copy; to imitate.
To walk; to go; to travel.
To walk over; to pass through; to traverse.
To follow the execution of the program by making it to stop after every instruction, or by making it print a message after every step.