Ubuntu – Starting a script in a Desktop icon

What will most probably solve your problem is to do the following:

1. Open the application

2. When it is running, open a terminal and type:

   xprop WM_CLASS
   

3. Then click on the open application window.

4. The output will look like (example gedit):

   WM_CLASS(STRING) = "gedit", "Gedit"
   

5. Use the first part (in this case would be gedit), to compose a line in your .desktop file:

   StartupWMClass=<string>
   

   (replace <string> with the actual (first part of the) output of xprop WM_CLASS, e.g. StartupWMClass=gedit)

Now try again (you might have to log out / in), most likely the application will appear in the launcher under its own icon.

Explanation

• When an application starts up correctly from a launcher (.desktop file), but another icon appears with only a generic icon (question mark), it is most likely that the application window and the launcher do not connect for some reason, and the launcher does not recognize the application's window as "his". This is often the case when a script or a non- standard application (-command) is used. In those cases the StartupWMClass= line is often the solution.

Ubuntu has something called a .desktop file, which acts as a shortcut to whichever app you want. You can specify an icon you want, the name of the shortcut, the description that appears when you hover over the shortcut, and a lot of other stuff. It's not the easiest setup, but it's not hard, either. Here's how to do it.

1. Open a terminal (Ctrl+Alt+T), and run gedit ~/Desktop/Arduino.desktop.

2. In the text editor window that opens, paste this:

    [Desktop Entry]
    Name=Arduino
    Comment=Arduino IDE
    Exec=/path/to/the/arduino/executable
    Path=/path/to/the/arduino_folder/
    Icon=/path/to/arduino/icon.png
    Terminal=false
    Type=Application
    Categories=Utility;Application;Development;
   

3. Edit the Exec,Path, and Icon fields to point to the appropriate locations.

4. Save the file and close Gedit.

5. Now, go to your Desktop folder and test the shortcut bu double-clicking it. If it works, you can drag the icon to your launcher to have it there, as well.

NOTES:

1. You may get a warning when you try to use the .desktop file, telling you it is not trusted, or something similar. If you see this, right click on the file, go to Properties >> Permissions and check the box that says something like Allow executing file as program. The warning will be gone.

2. Remember to use absolute paths in the desktop file. Don't use relative paths. An example of an absolute path is /home/username/arduino-1.6.7/. A relative path is something like ~/arduino-1.6.7 (the ~/ points to your user folder) or ./arduino-1.6.7 (./ means whatever folder you're currently in, which would be the Desktop in this case).

If you need any help, comment.