Welp, I just apt purge'd damn near everything except the kernel. How's your Friday going?

the truest form of Linux, without all the GNU bloat, well done! :)

Couple days ago I accidentally removed a package, not fully understanding what would happen. Ended up logging out thinking nothing of it. Couldn't log back in as there were zero sessions available. Also, for some reason a huge on-screen keyboard kept popping up a lot when I'd click on the login panels things.
I am very grateful my distro came with Timeshift by default and that I had a backup from the day before to fix everything. Also glad Rescuezilla allowed me to install Timeshift and restore.
Doesn't matter who you are or what you believe, it's definitely a rite of passage to break your system once. That is something I'll always agree with.

Last week I accidentally overwrote my configuration.nix file with garbage. If you use NixOS this should fill you with horror. If you don't, that file contains a description of your entire system -- all the packages as well as many settings tweaks to anything from GUI apps to core kernel & systemd options.
I have now learned my lesson and started using git to track my changes. Tbh, I was naively expecting to be able to roll back to a previous config and pull out my configuration file, but that's not how it works. Happily I had already split out the most difficult to reproduce sections into their own files (mostly networking stuff), so it wasn't that catastrophic, but it still turned a few minutes of tinkering into a couple hours of forehead-smacking.

Lol Nvidia has quiet the reputation in the Linux world. Keep at it though. We all make mistakes.

My first adventure in Linux back in 2003. No idea how I achieved this, but from memory I just reinstalled and all was well.
- GRUB
- i for one welcome our grub bootlorders
- "AI is gonna take over the world"
  Grub: "Hold ma beer"

If you are trying a new install go for something with timeshift or Silver Blue, OpenSUSE snapshotting. You can trash the whole setup, then reboot to the previous state. A catastrophic failure becomes a 1 minute fix.

If you don't mess with the partitions during the install and don't format, and make the same username, you should be back to normal after a reinstall. Take a backup offline, of course.
- make sure not to reformat though. it can be a problem depending on the installer his distro uses.
  i think its safer to just save the home folder, and replace it later when the system is installed.

Ahh, baby steps.
Around fours years ago I was still using Arch and I somehow decided to try LFS on my main machine (bare metal unfortunately). Started compiling coreutils but as I forgot to specify the build directory to gmake, my /usr/bin directory was being emptied to make space for the coreutils compilation process. Bricked my whole installation.
Now I'm smarter than four years ago as I mainly use NixOS.

Can i just reinstall to my root partition and have my home partition work as expected?
Yes, but you might have to muck around with /etc/fstab. The reason is because when you install to your root partition, the installer will create a new /home in that root partition. (Unless you have an installer that's smart enough that you can tell it otherwise.)
You should be able to mount the partition in any case, but to have the system recognize it as /home it has to be properly set up in fstab.

Does anyone sell 'Yes, Do As I Say!' stickers?
You could possibly recover from that on console, just install few metapackages. And have backups.
- it's "Yes, do as I say!"
  
  Dammit, my organic memory failed yet again. It's been a while since I've seen that prompt (and I have agreed to that as well at least few times).
  
  Yeah OP is not gonna die on that

I overwrote my ssh private key with rsync. Fortunately I had special cron job running on my servers that updates ssh public keys on a server with ssh public keys from my github account, so I just had to upload a new key to the github and wait for a few hours.

Average .ml purges

congrats you're ready for the next step: a declarative package configuration like (non-)guix or nixos

One of us. One of us

FWIW each new install is faster, especially if you write down the "weird" steps.

My pacman -Syu crashed on my old laptop and at this point I might just reinstall it, this time putting on some sort of a snapshot solution on it like on my main laptop
- Btrfs with pre and post pacman-triggered snapshots. Only had to use it once, but it was very smooth.
  
  yeah, that's how I roll there

TimeShift. Life saver, and great tool for learning without having to worry about breaking shit permanently.
- Yup, its super easy
  https://itsfoss.com/backup-restore-linux-timeshift/

(it was nvidia related)
lel we got 'im, boys. /s

ctrl + z

Nice day to move to nixos ;)
- See my top-level comment; even if they're ready for the complexity, it doesn't protect you from a similar mistake!
- OP mentioned having used Linux for 4 weeks. If they are interested in learning more about Linux, I feel like even Arch would be a better next step.
  I love NixOS and have been using it for over a year at this point but sometimes when things don't work I feel like I'm banging my head against a wall. I've been using Linux for ~7 years now.

Migrating a 8 year old server to fresh new hardware. Can't believe you can basically just rsync one computer to another
- You can indeed.

I accidentally interrupted a system upgrade, breaking networking and package manager, among other important bits

I feel your pain 😅🫠
Yeah, just to add another confirmation to the other comments, if you have a separate home partition you can reuse it with a new / partition and expect it to work fine. The only stuff that gets saved in your home folder is comfiguration files for your apps, along with whatever actual files you have stored. You can even swap distros (Ubuntu/Arch) and keep your home folder, though sometimes the config files and settings don't translate perfectly.

On the bright side, it's never been a better time to switch to an immutable distro...

If anything can be salvaged, I'd suggest backing those up, and then proceeding to make a fully fresh install. That will ensure you don't come across issues inherited from the previous blunders, and also, I think, will give you the chance to take the same steps, but wiser than before, and so able to avoid the issues you either caused or came across. (Also something I'd recommend maybe around every 1~2 years, precisely because of being able to restart but wiser)

Congratulations OP!
About a year and a half ago I nuked my root partition with sudo rm -rf /*. Fun times.
- That’s just how you unlock the hidden boss fight.

Nice, you get a sticker!

Reinstall using btrfs as the root files system and enable automatic snapshots. The data on your home partition will be fine, just make sure the installer doesn't format it.
- I really need to learn how to do that. I installed SuSE something on my laptop and selected that file system but couldn't find how to do the snapshot stuff. I'm sure I'm just dumb, but also exhausted, and mentally drained.
- More technology does not fix daft manoeuvres! You do learn by your mistakes but keep the environment as simple as possible and add complexity later. Just like I didn't back in the day! Mind you we lived in greyscale back then.
  I've been a Linux sysadmin (and I have a lot of customers) for around 25 years now and only during the last 18 months have I bothered with something funky like ZFS - Proxmox is why and that's thanks to Broadcom deciding to fuck up VMware. I have done a lot of migrations and many more to follow. BTRFS is coming along but it is not for me quite yet.
  Backups are golden. Even a simple rsync of /home and /etc to a USB stick or two will do for starters. If you want a challenge then try getting the Veeam agent for Linux working, with secure boot. I suggest not yet (secure boot). However, Veeam do a community edition which is free for 10 workloads (VMs/agents). I recently recovered a HP laptop running Home Assistant to a Thinkpad and everything just worked apart from the network, which is pretty reasonable and it took about 20 minutes.
  So, I suggest that you get your backups in order first and then you can muck about with confidence. If you have some time and energy then do have a go at Gentoo and/or Arch. I ran Gentoo as my daily driver for some years and now I never fear anything IT related.
- Better yet, backup /home to a separate disk and replace after install.

I've done the same thing (Nvidia related) on a machine hooked up to an expensive scientific instrument. Didn't get any other work done that day... Ugh.

Recently upgraded a laptop that had been on the shelf for 5 years up to latest version. Flawless one-step upgrade! nixos. Things never get in a tangle where installing and uninstalling packages leaves random artifacts behind. If you saved it to version control, you can return to a past system configuration and the only thing different is your home directory data.
And yes, if you have a home partition and root partition, that's exactly what you can do. That's the beauty of that approach. But back it up!

Welcome to the club, here's your penguin 🐧

Back the hell up. Seriously. I cannot overstate how peaceful life is when your ass is properly covered.
- This is my favorite song about proper Linux practices: https://youtu.be/WpQrAbkM3dI

Try to fix it.

Yes.
I wouldn't do it without tests and "enough" experience.
I would backup first.
Then I would install an atomic distro because I wouldn't want to care about this ever again

I try to keep everything I care about in one folder that is backed up regularly, so it’s not such a big deal to reinstall the OS.

Spent half the day debugging wifi and kernel panic issues during boot. What finally fixed it was adding 5 sec delay to iwd service so wifi card firmware can do it's thing (or at least I think thats why it helped).

The best way to learn something is by hurting you.

What where some of the commands you where unsure of? Might be able to help if it's a common problem like smb sharing.