All programs in a Linux distribution such as Ubuntu are installed from special deb packages. It is such an extension that is commonly used. In different OSs, they may differ, for example, in Windows, which is familiar to all of us, special .exe files are used. Typically, on an Ubuntu system, to build a program from the repository, it automatically downloads and installation of deb packages begins. But sometimes you have to install the program manually, for example, if there is no Internet, or the installers are very large (in particular, games).
Windows users probably got used to the latter method. Those. just download the file with the desired extension, double-click and follow the instructions by clicking the "Next" button. The Linux system for this method has its own differences.
General recommendations
For the correct search and installation of programs , the following sequence of actions is recommended:
1) Go to the Application Center and try to find the required program there.
2) If you couldn’t find it in the standard source, you can go to the official website of the developers and see their repository for installation or a link to the PPA there.
3) In the case where the site only offers to install a deb package, then you need to download it and work with it further.
4) It also happens that you can find only the source code, in this case you have to build the program yourself.
The best solution is to install deb packages from the repository only for the reason that in the future it will be much easier to update the program. The service for organizing updates on your system will find the latest versions automatically.
It is also worth noting that in the official repositories of the program it is more reliable than in the sources of the developers, since the latter contains newer versions, although not as stable.
Installing deb-files is divided into 2 ways: in graphical mode and terminal.
Installation in graphical mode
First you need to find the package in the file manager, and then double-click on it. Next, the graphical shell of the program will appear on the screen, and if an older program is present in official sources, the user will be informed about this. You can close this popup . After that, you need to click "Install Package", after which you will be asked to enter the administrator password, because any such action should be carried out only with his permission. Then the installation process will begin. Upon completion of this, you can close all windows and go to the program itself from the Ubuntu menu.
Installation from the terminal
For the deb-package installation to be correct, you need to go to the appropriate folder in the terminal containing the desired file and type the command: "sudo dpkg -i package_name.deb".
Next, you need to follow all the instructions on the screen. If everything went well, a message appears stating that the program was installed successfully. In Ubuntu, deb packages may not contain the necessary dependencies for this program, all the required names of additional packages will be indicated, they need to be installed in the same terminal.
conclusions
Only the most necessary and brief description of the installation was presented. There are many special cases, each of which has a mass of its subtleties.