For Arch you run pacman -Qe which lists all installed packages that were not installed as a dependency. I output that to a location via golang script which is monitored by the pCloud client for automatic backup along with a lot of other configs from $HOME/.config. I then have a systemd service that fires the script and a timer to kick off that service periodically.

NixOS has a config file, you backup that file, you can duplicate your system with it.

OpenSUSE has an AutoYast system where you can build a config for the next install.

OpenSUSE microOS has ignition and combustion files to replicate a system from scratch. For those that don't like hand typing a config file there is this web based tool to write out a file based on selections https://opensuse.github.io/fuel-ignition/

You can install all apps through the command line. Just write a shellscript with all the commands and run it when you're doing your reinstall.

Surprised nobody said this yet, but I use ansible. I also use it to have the same install on multiple machines independently (something that doesn't work by just having a dedicated home partition).

But it's a bit of maintenance to keep modifying my dotfiles, certainly not as easy as your old apps aisle.

use your distros method of listing every installed package and modify it to be a install command

For me that's the main benefit of using home-manager on nixos and other distros. You basically just make a list of packages, and install/update them through home-manager.

I think a sync method or a way to dump settings and apps would be cool.

If you can't remember what to reinstall, was it really that important? Packages are so quick and easy to install that I just install them the first time I try to use them and find them missing.

Assuming you are using an apt/dpkg distro:

Save the list of packages on your reference system:

dpkg --get-selections > packages.lst

Then install packages based on that list on your target system, after updating the list of available packages:

dpkg --merge-avail <(apt-cache dumpavail)
dpkg --clear-selections
dpkg --set-selections < packages.lst
apt-get dselect-upgrade

In APK based systems (Alpine, Chimera, Adelie) there is /etc/apk/world

It is a list of all the packages you have explicitly installed. When you add and remove from this list (all apk does), the system solves for dependencies and makes sure you have the right packages installed.

You could bring up a new system by updating this file.

I'm not advocating for anything, but if I remember correctly, flatpaks are typically installed in user home directory. If that's the case, then it's just a matter of copying a directory and installing flatpak. I might be wrong though.

instead of searching and installing all your apps one-by-one

And... that takes what, a good all 5 minutes?

Honestly unless you either re-install an OS frequently (which is a weird thing to do on a day-to-day system) or plan to go offline for a long period of time I bet you'd spend more time finding a "solution" then not doing so manually.

I'm not you but when I install a fresh OS (maybe once every couple of years, at most!) on my desktop (not counting other devices, handheld, servers, etc) I install

• Firefox (if it's not already by default, if it's ESR then I might get a different update mechanism)

...well honestly that's it!

Then yes as I start to work I add KDEnlive, OBS, Blender, Cura, OpenSCAD, etc.

My point being that I can't imagine a moment when, as you start the OS you actually need all the other software at the same time. You usually need one, then another, e.g. Inkscape to edit a PDF document you just received, then you pass the extract image to e.g. LibreOffice Writer.

So... not having everything from the start is IMHO a good moment to consider what you actually need, keep things lean.

TL;DR: there are technical solutions but on a desktop connected to the Internet it's not worth it.

PS: I do personally keep my bash history or my ~/bin/ and ~/Apps/~ directories across installations (because I do keep ~` on a dedicated partition) with some AppImages in but honestly I don't rely on these.

Just use appimages. Works for a lot of things that don't require full integration.