How to suppress a message from a program while installing it to use in a bash program?

**PROBLEM:** I have a program written in bash that does a lot of stuff like install new software on the system. One of the programs it installs has an extravagant message appear where you get some info about usage and the configuration file and what it does if you don't edit the config file. **And then waits for user input.** This message is a dialog kind of message in a GUI: The program that displays this message is portsentry and the system is Debian Stretch. **QUESTION:** How can I suppress this message so there is no communication between my program and the user?