stty is a tool used to set the input and output settings for the terminal communication interface . It can also read the settings of the terminal communication interface .

The terminal communication interface settings that can be set and read by stty are divided in the following categories :

PGP stands for pretty good privacy . It is a software used for digitally signing data in order to make sure that it has not been tampered with . It is also used for data encryption and decryption .

PGP also provides keys management . Keys are used for singing and verification , and or , encrypting and decrypting of data . An example of key management is key creation or deletion .

Each distribution has a release file which contains indices of binary and source packages that can be installed from this distribution .

apt-key is used to add , delete , list , and export public keys used by apt to verify the signature of a release file .

Conformance as defined by the c standard is two parts : conformance of a program and conformance of an implementation .

Concerning the conformance of a program , a c program can either be : strictly conforming or conforming . As for the conformance of an implementation it can be either hosted or freestanding .

The /etc/apt/preferences file is used to control the priority of a source distribution in the /etc/apt/sources.list , and it is also used to control the priority of individual or multiple binary packages .

In this tutorial , we will explain what is a default priority and what is a target release . We will also explain the /etc/apt/preferences record formats and how a priority and a package are selected .

The /etc/apt/sources.list file contains a list of sources from which apt can download indexes of binary and source packages .

In this tutorial , we will explain the format of a source in sources.list . We will also explain what is an index file , what is a distribution , what is a distribution release file , what are a distribution components , and we will give an example of a sources.list file .