I would like to set an environment variable so that it is set when I launch a specific Flatpak application, and only set for this application. How do I go about doing this in a permanent manner?
You can do this via the
flatpak override command.
To set only one environment variable you can use this syntax:
flatpak override --env=VARIABLE_NAME=VARIABLE_VALUE full.application.Name
To set multiple environment variables you can use this syntax:
flatpak override --env=VARIABLE_NAME_ONE=VARIABLE_VALUE_ONE --env=VARIABLE_NAME_TWO=VARIABLE_VALUE_TWO full.application.Name
This will set it globally and therefore requires you to run the command as root. If you want to do this for your current user, you can add the
--user parameter to the command, like so:
flatpak override --user --env=VARIABLE_NAME=VARIABLE_VALUE full.application.Name
Source and further reading: http://docs.flatpak.org/en/latest/flatpak-command-reference.html#flatpak-override
The Flatseal application lets you set environment variables and other things relating to your installed flatpaks in a convenient fashion if you are GUI sort of person.