diff --git a/src/ex_cmds.h b/src/ex_cmds.h
index 3ebbf23..8da0da1 100644
--- a/src/ex_cmds.h
+++ b/src/ex_cmds.h
@@ -707,6 +707,9 @@
 EXCMD(CMD_history,	"history",	ex_history,
 	EX_EXTRA|EX_TRLBAR|EX_CMDWIN|EX_LOCK_OK,
 	ADDR_NONE),
+EXCMD(CMD_horizontal,	"horizontal",	ex_wrongmodifier,
+	EX_NEEDARG|EX_EXTRA|EX_NOTRLCOM,
+	ADDR_NONE),
 EXCMD(CMD_insert,	"insert",	ex_append,
 	EX_BANG|EX_RANGE|EX_TRLBAR|EX_CMDWIN|EX_LOCK_OK|EX_MODIFY,
 	ADDR_LINES),