How to Alert before SSL Certificate expire?

Tried create a .sh file as per above script in v11 LTM but no output as such.

1. Create and edit the script:

   vi certmonitor.sh

2. Copy the above code to the script and save it.

3. Chmod the script to make it executable:

   chmod 755 certmonitor.sh

4. Run it:

   ./certmonitor.sh

There are two versions of the script above. The first is for 11.x, and the second is for 10.x.