A very old patch sitting in my tree..

When rc scripts are started from interactive shell, be nice and when user
tries to start an unconfigured service, point him to rc.conf(5) and tell
him about the one* keyword.  Also be more user friendly when an unknown
argument is entered.

Example:

# /etc/rc.d/cron start
$cron is not enabled - see rc.conf(5).
Use the following if you wish to perform the operation:
  /etc/rc.d/cron onestart

# /etc/rc.d/cron nonsense
/etc/rc.d/cron: unknown directive 'nonsense'.
Usage: /etc/rc.d/cron [fast|force|one](start stop restart rcvar  status poll)

Inspired by discussion on tech-userlevel:

http://mail-index.netbsd.org/tech-userlevel/2007/02/13/0010.html
http://mail-index.netbsd.org/tech-userlevel/2007/02/13/0011.html
http://mail-index.netbsd.org/tech-userlevel/2007/02/13/0012.html

Reminded about it and reviewed by <lukem>

(salo)