Вот цитата из man rc.subr:
argument may have one of the following prefixes which alters its operation:

fast   Skip the check for an existing running process, and sets rc_fast=YES.

force  Skip the checks for rcvar being set to ``YES'', and sets rc_force=YES.  This ignores argument_precmd returning non-zero, and ignores any of the required_* tests failing, and always returns a zero exit status.

one    Skip the checks for rcvar being set to ``YES'', but performs all the other prerequisite tests.