Unix-APT sources.list configuration

I recently encountered a situation when I took an ElasticSearch-7.x installation on my machine and later ran into some trouble and decided to move on ElasticSearch-6.x on my system. I uninstalled Elastic-7 from my system and later whenever tried to reinstall it, it was reinstalling Elastic-7.x in the system. Here is where I got to know about sources.list, so decided to take a deep dive in this.

The configuration for controlling the versions to be installed lies in /etc/apt/sources.list . Here, one can specify what version on what package one wants to download in the Unix system.

APT stands for Advanced Package Tool which works with core libraries of Ubuntu and other Debian based distributions and manages installations on your Linux based machine.

So, you here you can change the version of the artifact which you want to install on your system.

If you have made any changes into the configuration in sources.list. You need to run the below command to update package manager on the new repository.

sudo apt-get update

If you see this file the links have various other details as well.

Here is the meaning of them-

• Main — officially supported, open-source software. Whatever packages which are officially installed and are open-source are indicated here.
• Restricted — officially supported, non-open-source software ex: hardware drivers etc.
• Universe — Open source softwares which are configured
• Multiverse — unsupported, non-open-source and patented software.