/usr/share/icons
system icon folder
/usr/share/applications
system menu folder, to add an item to the application menu in the upper left corner, you can add a .desktop file here
~/.local/share/applications
user menu folder, menu items added here will only be displayed in the current user's application menu.
But there is a strange problem: if you use the "Edit menu" function of the right button of the application menu to add menu items, the menu items that appear will appear in this folder, but there is no . You can see it in Nautilus, but you can't see it with ls -a. Double-click this file to start the program directly. Double-clicking other .desktop files does not work. What a puzzling question...
~/.local/share/icons
user icons folder
The settings.menu and application.menu in ~/.config/menus seem to be used to define menu categories. If some programs are uninstalled but the menu is still there (such as WINE), you can try to delete the contents of the applications-merged directory.
By the way, record the corresponding relationship of the .desktop file application classification:
- Internet Network
- Office Office
- Image Graphics
- Sound and Video AudioVideo
- System ToolsSystem
- Programming Development
- Auxiliary optionsUtility
- Preferences Settings