Suppress Installation Package Prompts Completely or Preconfigure Installation Question Answers

Automating the installation of software via bash scripting on Linux can be difficult.  However, in debian and its related distributions such as Ubuntu, you can simplify the installation of packages by using a few tools.  One of these tools is called debconf-utils.  If installation packages such as MySQL or PHPMyAdmin ask configuration questions, you can provide a default set of answers without being prompted.  This is excellent for testing scripts or automating installation for users who may not know how to appropriately answer these questions.

Basically, with debconf-utils you can pre-answer these questions so that no prompts show up!

To install, run this command:

sudo apt-get install debconf-utils

To get a list of questions an installer might ask, first install the package on a test machine where you're writing the script normally.  For example, let's install phpmyadmin:

sudo apt-get install phpmyadmin

Now, to retrieve a set of questions phpmyadmin may ask, you can run this command:

sudo debconf-get-selections | grep phpmyadmin

In your bash script, you can now pre-answer certain questions by including your preconfigured answer commands before installing the package.  For example, when phpmyadmin installs, it asks for the MySQL root user password.  You can skip this prompt and define what the MySQL root password should be by using this command in your script:

echo 'phpmyadmin phpmyadmin/mysql/admin-pass password 1234' | debconf-set-selections

password defines the type and 1234 sets the password to 1234.
You can also suppress questions entirely by using the following command in front of your install command:

DEBIAN_FRONTEND=noninteractive sudo apt-get install phpmyadmin

Default configuration will be used during the installation of the phpmyadmin package, which means it may not work after being installed because some configuration options should be answered.  So, use both combinations for various packages to fit your needs!