Index: etc/rc.d/dhclient
===================================================================
--- etc/rc.d/dhclient	(revision 226879)
+++ etc/rc.d/dhclient	(working copy)
@@ -22,7 +22,14 @@
 dhclient_pre_check()
 {
 	if [ -z "${rc_force}" ] && ! dhcpif $ifn; then
-		err 1 "'$ifn' is not a DHCP-enabled interface"
+		local msg
+		msg="'$ifn' is not a DHCP-enabled interface"
+		if [ -z "${rc_quiet}" ]; then
+			err 1 "$msg"
+		else
+			debug "$msg"
+			exit 1
+		fi
 	fi
 }
 
Index: etc/rc.subr
===================================================================
--- etc/rc.subr	(revision 226878)
+++ etc/rc.subr	(working copy)
@@ -1117,7 +1117,7 @@
 #
 rc_usage()
 {
-	echo -n 1>&2 "Usage: $0 [fast|force|one]("
+	echo -n 1>&2 "Usage: $0 [fast|force|one|quiet]("
 
 	_sep=
 	for _elem; do
Index: share/man/man8/rc.subr.8
===================================================================
--- share/man/man8/rc.subr.8	(revision 226878)
+++ share/man/man8/rc.subr.8	(working copy)
@@ -339,7 +339,7 @@
 being the list of valid arguments
 prefixed by
 .Sm off
-.Dq Bq Li fast | force | one .
+.Dq Bq Li fast | force | one | quiet .
 .Sm on
 .It Ic reverse_list Ar item ...
 Print the list of
@@ -427,6 +427,22 @@
 being set to
 .Dq Li YES ,
 but performs all the other prerequisite tests.
+.It Li quiet
+Inhibits some verbose diagnostics.
+Currently, this includes messages
+.Qq Starting ${name}
+(as checked by
+.Ic check_startmsgs
+inside
+.Nm )
+and errors about usage of services that are not enabled in
+.Xr rc.conf 5 .
+This prefix also sets
+.Va rc_quiet Ns = Ns Li YES .
+.Em Please, note:
+.Va rc_quiet
+is not intended to completely mask all debug and warning messages,
+but only certain small classes of them.
 .El
 .Pp
 .Ic run_rc_command