cowsay-off software package provides configurable talking cow (offensive cows), you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install cowsay-off
cowsay-off is installed in your system.
Make ensure the cowsay-off package were installed using the commands given below,
$ sudo dpkg-query -l | grep cowsay-off *
You will get with cowsay-off package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Games |
| Package | cowsay-off |
| Version | 3.03+dfsg1-16 |
| Description | configurable talking cow (offensive cows) |
| Sub Section | Games |