sysrc(8) on FreeBSD
The text cced71027bd8, as FreeBSD 9.3-RELEASE shipped it.
safely edit system rc files
Flags it lists
-
--help -
--version -
-A -
-D -
-F -
-N -
-R -
-a -
-c -
-d -
-e -
-f -
-h -
-i -
-j -
-n -
-q -
-v -
-x