apt-config is an internal program used by various portions of the APT suite to provide consistent configurability. It accesses the main configura-tion file /etc/apt/apt.conf in a manner that is easy to use by scripted applications.
apt-config Syntax
apt-config [options] command
If you run directly from command line you should see the following screen
# apt-config
apt 0.6.45 for linux [...]