diff --git a/tools/asciidoclint.py b/tools/asciidoclint.py
index c1d30134..4d0774dd 100755
--- a/tools/asciidoclint.py
+++ b/tools/asciidoclint.py
@@ -273,7 +273,7 @@ def main():
             sys.exit(1)
         _, ext = os.path.splitext(f)
         if ext != ".adoc":
-            print("'{}' does not have an .mdk extension")
+            print("'{}' does not have an .adoc extension".format(f))
             sys.exit(1)
 
     conf_path = None