diff --git a/src/org/rascalmpl/interpreter/Evaluator.java b/src/org/rascalmpl/interpreter/Evaluator.java
index 5183ce362d..f36939a9d5 100755
--- a/src/org/rascalmpl/interpreter/Evaluator.java
+++ b/src/org/rascalmpl/interpreter/Evaluator.java
@@ -1406,6 +1406,7 @@ public void printHelpMessage(PrintWriter out) {
         out.println("e.g. profiling    true/false");
         out.println("     tracing      true/false");
         out.println("     errors       true/false");
+        out.println("     debugging    true/false");
         out.println(":edit <modulename>         Opens an editor for that module");
         out.println(":test                      Runs all unit tests currently loaded");
         out.println();