Yes, we have a backup of your data.
Yes, we have a backup of your data.
Usually you don't have to backup the apps themselves, just their configurations. I keep my home folder safe with rsync (leaving out certain temporary folders). Be sure to add hidden spots like .local, .mozilla, .thunderbird—they hold personal app settings. Once I reinstall Linux and re-add these programs, restoring the home directory should recover most of my in-app preferences (such as bookmarks and Firefox settings)
Settings are saved in your home folder under ".config" and ".local" folders, with some unusual paths. For packages, you can't directly manage them in a GUI, but via terminal commands you can list installed apps, filter by distribution, and save the results to a text file. To reinstall using that list, run the package manager with the file as an argument.
You can safeguard your configuration files using rsync. With NixOS, it's simple to restore previous versions of your applications. (reproducible setup)