.desktop files: Launcher icons on Linux
Heya! Just thought I'd write a quick reminder post for myself on the topic of .desktop files. In most Linux distributions, launcher icons for things are dictated by files with the file extension .desktop.
Of course, most programs these days come with a .desktop file automatically, but if you for example download an AppImage, then you might not get an auto-generated one. You might also be packaging something for your distro's package manager (go you!) - something I do semi-regularly when apt repos for software I need isn't updated (see my apt repository!).
They can live either locally to your user account (~/.local/share/applications) or globally (/usr/share/applications), and they follow the XDG desktop entry specification (see also the Arch Linux docs page, which is fabulous as usual ✨). It's basically a fancy .ini file:
[Desktop Entry]
Encoding=UTF-8
Type=Application
Name=Krita
Comment=Krita: Professional painting and digital art creation program
Version=1.0
Terminal=false
Exec=/usr/local/bin/krita
Icon=/usr/share/icons/krita.pngBasically, leave the first line, the Type, the Version, the Terminal, and the Encoding directives alone, but the others you'll want to customise:
Name: The name of the application to be displayed in the launcherComment: The short 1-line description. Some distros display this as the tooltip on hover, others display it in other ways.Exec: Path to the binary to execute. Prepend withenv Foo=baretc if you need to set some environment variables (e.g. running on a discrete card - 27K views? wow O.o)Icon: Path to the icon to display as the launcher icon. For global.desktopfiles, this should be located somewhere in/usr/share/icon.
This is just the basics. There are many other directives you can include - like the Category directive, which describes - if your launcher supports categories - what categories a given launch icon should appear under.
Troubleshooting: It took me waaay too long to realise this, but if you have put your .desktop file in the right place and it isn't appearing - even after a relog - then the desktop-file-validate command could come in handy:
desktop-file-validate path/to/file.desktopIt validates the content of a given .desktop file. If it contains any errors, then it will complain about them for you - unlike your desktop environment which just ignores .desktop files that are invalid.
If you found this useful, please do leave a comment below about what you're creating launcher icons for!