terminal/tools: hwatch

docs/terminal/tools.md

@@ -21,3 +21,9 @@ Output to `stdout` and only update when output changes:
 ```sh
 hwatch -b date
 ```
+
+Watch for changes on a website and play a sound on changes:
+
+```sh
+hwatch -A beep.sh -b "curl -I https://example.org | grep '^HTTP'"
+```