In Ubuntu 16.04, the Application Manager is launched by default (aka "Ubuntu Software")
instead of the Application Center (also known as the "Ubuntu Software Center"), as it was in 14.04.

It turns out that they show the user different applications:
The application center knows gksu, and the application manager does not! evidence

Is this how it was conceived that the Application Manager (which is "Ubuntu Software" of 16.04) filters the applications?
Maybe you need to configure it somehow?

Upd: It suddenly dawned on me that the Application Manager gives access to the Программы и обновления in the menu. These are the same Программы и обновления that are available from the Параметры системы and from the Application Center -> Правка -> Источники приложений...

It turns out that both programs use the same repositories.
So why are the results different?

Upd2. Another picture: for Spyder3, the Application Manager gives a rating of 3 stars from 3 voters, despite the fact that according to his own data, 3 people gave him 5 stars. screenshot

1 answer 1

Application Center is an old GUI program for managing installed software that was used in Ubuntu until 16.04. Later it was decided to abandon its further development in favor of the Application Manager from the Gnome project. Ubuntu comes with a highly modified version, since the internal architecture of this program is designed for this. She herself is written in C and works quite quickly (unlike the previous application center in Python), has a developed system of plug-ins.

However, these programs are fundamentally different in their approach. The Gnome Application Manager (and Ubuntu) uses AppStream as a source of software information — a database with metadata about program components in the open source ecosystem. Apt regularly downloads it from the update mirror using the apt update command or automatically. Debian-based distributions use the DEP-11 format.

For some reason, currently, this database mainly contains information about programs that have a graphical user interface. And due to the fact that for the most part this database is built by an automated appstream-generator tool based on .desktop files, the implication is valid: "If a package with a program installs a .desktop file with an icon for a menu, this application can be found in the AppStream."

But in fact, in the application manager , a filter is still applied — it displays only programs with a GUI in the list, that is, those marked with type=desktop-application . It is assumed that if you need a console program, it is much easier to put it directly with Apt.

findings

The application manager uses AppStream - a distribution-independent list of applications in the world of Linux and open source software. However, the packages are installed from their usual repositories that Apt uses.

The application center uses the Debian or Ubuntu archive infrastructure directly, without resorting to an AppStream or DEP-11.

Utility

  1. You can access the AppStream database stored on your computer from the command line using the appstreamcli utility from the appstream package.

  2. The lists themselves in the DEP-11 format are stored in the /var/lib/app-info/yaml .

  3. However, user reviews you will not find there (there are only descriptions). Estimates of programs are downloaded from the server reviews.ubuntu.com once every three months, immediately all available, comments - when you open the page with the application. The plugin /usr/lib/gs-plugins-9/libgs_plugin_ubuntu-reviews.so is responsible for /usr/lib/gs-plugins-9/libgs_plugin_ubuntu-reviews.so .

As for gksu: I have the Debian unstable repository connected, and gksu.desktop is listed in yaml from there , so the Application Manager finds it in the search. However, it is worth refraining from using this utility - it is recognized as obsolete and will be removed in the future.

  • one
    1. I agree that the Application Center is slowing down, but still I’ll use it for now. Firstly, I do not like the fact that I am filtered information, and secondly, see the Upd2 question. - user244413
  • 2. How can I edit system files instead of gksudo? - user244413
  • Well, I already mentioned the ratings, but I’ll repeat: the stars at the top are loaded once every three months for all the programs at once, the histograms of ratings (and comments) for each specific application are loaded when you open the page with the program. Perhaps the situation has changed in the period between these downloads; although you shouldn’t rule out some unplanned mistake. - mymedia
  • About gksu and gksudo: it’s suggested to use the PolicyKit interface as a replacement, unfortunately, not all programs support it yet. One way or another, a transition to Wayland is planned in the near future, and there these tools do not work at all (as Jeremy Bicha claims). - mymedia