Debian Linux, by default, uses the deb packages, the aptitude package manager and the apt-get command-line tool, which enables users and admins to administer the installation, removal and updating of all the software on their systems (those which are installed and managed by apt). In this tutorial I’ll show you how to update your software on Debian Linux without upgrading the Operating System version by running one command on your bash shell terminal. For this to work, you need to be part of the “sudo” group on your system. You will also need to know your user password.
apt-get, the APT-based command-line tool for handling packages, provides a simple, safe way to install and upgrade packages – The Debian GNU/Linux FAQ
Chapter 9 – Keeping your Debian system up-to-date
Update package list and update the software packages to the newest version supported by your system:
Run the following command on your terminal emulator, with a bash shell.
sudo apt-get update && sudo apt-get upgrade
The “&&” bash command tells your system to run one apt-get command after the other as long as the first command completed successfully. “apt-get update” updates the package lists on your system, and “apt-get upgrade” update your software to the newest stable versions supported by your current OS version. After entering these commands, your system will ask you to confirm changes to the software. You may also add the “-y” argument to “apt-get upgrade” command to confirm almost all changes without further interactions.