The awk's split() starts numbering array indices at 1 not 0.

src/etc/mklogin.conf

@@ -5,7 +5,7 @@
 #
 # Usage: mklogin.conf [overrides_file] < login.conf.in > login.conf.out
 #
-# $OpenBSD: mklogin.conf,v 1.4 2009/03/24 20:34:51 sturm Exp $
+# $OpenBSD: mklogin.conf,v 1.5 2010/12/02 20:41:13 millert Exp $
 
 BEGIN {
 	# Default substitutions
@@ -24,7 +24,7 @@ BEGIN {
 	if (ARGC > 1) {
 		while (getline override < ARGV[1]) {
 			split(override, ov)
-			values[ov[0] ""]=ov[1] ""
+			values[ov[1] ""]=ov[2] ""
 		}
 		ARGC--
 	}