diff --git a/content/AWS/04_intro_to_cli.ipynb b/content/AWS/04_intro_to_cli.ipynb
index 049e850..6ff3a4d 100644
--- a/content/AWS/04_intro_to_cli.ipynb
+++ b/content/AWS/04_intro_to_cli.ipynb
@@ -33,7 +33,9 @@
    "id": "c543528f",
    "metadata": {},
    "outputs": [],
-   "source": []
+   "source": [
+    "Test CLI"
+   ]
   }
  ],
  "metadata": {
diff --git a/preview-book.sh b/preview-book.sh
old mode 100644
new mode 100755