4BSD/usr/lib/lisp/step.ref

Stepper commands:

<return>	Continue stepping recursively.
b	cause a break
c	evaluate this expression without stepping, then resume stepping
d	call debug
g	turn off stepping mode and finish evaluation
h, ?	print this help
m	do a macro expansion
p	display current form in full (without &'s)
s	skip this one
q	quit (reset)

    ----> For more documentation see /usr/lisp/doc/step.doc