-t, --target-release, --default-release This option controls the default input to the policy engine. It creates a default pin at priority 990 using the specified release string. The preferences file may further override this setting. In short, this option lets you have simple control over which distribution packages will be retrieved from. Some common examples might be -t '2.1*' or -t unstable. Configuration Item: APT::Default-Release; see also the apt_preferences(5) manual page.
Apt's Default Priority Assignments If there is no preferences file or if there is no entry in the file that applies to a particular version then the priority assigned to that version is the priority of the distribution to which that version belongs. It is possible to single out a distribution, "the target release", which receives a higher priority than other distributions do by default. The target release can be set on the apt-get(8) command line or in the APT configuration file /etc/apt/apt.conf(5).
For example, apt-get install -t testing some-package
To configure the default release in the configuration file, use: APT::Default-Release "stable";
