diff --git a/aircon.sh b/aircon.sh
index f428bf8..05fe471 100755
--- a/aircon.sh
+++ b/aircon.sh
@@ -66,7 +66,8 @@ function usage() {
     echo "    -m          Generate a config file based on current aircon setup."
     echo "    -p          Profiler mode."
     echo "    -s          Validate config file then exit."
-    echo "    -S          Show configured rules in human-readable format."
+    echo "    -S[H]       Show configured rules in human-readable format"
+    echo "                (HTML if -H given, otherwise ANSI)."
     echo "    -w          List which zone owners' devices are available then exit."
     echo "    -t num      Specify degrees below min temperature before taking action."
     echo "    -T num      Specify degrees above max temperature before taking action."