gkrellmoon software package provides Gkrellm Moon Clock Plugin, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gkrellmoon
gkrellmoon is installed in your system.
Make ensure the gkrellmoon package were installed using the commands given below,
$ sudo dpkg-query -l | grep gkrellmoon *
You will get with gkrellmoon package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | X Window System software |
| Package | gkrellmoon |
| Version | 0.6-5 |
| Description | Gkrellm Moon Clock Plugin |
| Sub Section | X235 |