Would be nice to be able to just double click AppImage, answer a few questions (device, iso file location, mode) and… done! 😃

Might be useful to add two new arguments to force corresponding mode (e.g. --cli and --gui).

if [[ $DISPLAY ]] could be used to select default mode (or maybe build separate AppImage defaulting to GUI mode).

App can make sure it's ok to output to stdout with if [ -t 1 ], and use log file if not (e.g. app is launched via double click or cron instead of terminal).

I might come up with a PR when I have some time. Would it be better to do GUI as a separate script (kind of wrapper) or part of the main script?