Update bash-9-scripting.md

docs/pages/bash/bash-9-scripting.md

@@ -138,4 +138,6 @@ echo $var2
     ```
 
 
+## Increment a variable
+
 !!! question "Write a bash script called `count5.sh` that does the same as previously, and also report the total number of characters contained in all files"
\ No newline at end of file