What's (are) the funniest/stupidest way(s) you've broken your linux setup?

source ~/.bash_history
- Dear god
- That's the scariest horror story in 2 words I've seen so far
  
  I'm genuinely having a chuckle at how shocked people are at my submission, made my day xD
- Can a linux noob get an explanation of this?
  
  source is a bash shell built-in command that executes the content of the file passed as argument, in the current shell.
  ~/.bash_history contains all the commands you ever executed in bash (the default shell in most Linux systems)
- New fear unlocked
- i never thought i had a nuke that i can launch using one command
- Reminded me of this: https://github.com/jtroo/kanata/issues/595
  Same concept, different granularity!
- "Oh My..." thought in a George Takei voice
- Oh no. That fits the bill perfectly lol.
- Jesus Christ. It would be a good idea to format that file to have an exit as first line to avoid this

Perhaps not the same definition of "broken" that you're looking for, but when I first started using Linux, I was using Kubuntu as my first distro have some brief experimenting with Manjaro.
Anyway, back then, I for some reason had the Skype snap installed. Can't recall why I had it to begin with, but I decided later on that ofc I didn't need Skype, and of course uninstalled the snap.
A few days later, I was met with some storage issues, where I had a limited amount of storage left on my SSD. I'm sitting there a little confused since I swore I was using less storage, but I did a thorough cleaning of my computer by deleting files I didn't necessarily need, and uninstalling any programs that I hardly ever used. That seemed to do the job, even if it was less storage space...
Until the next day, when the storage was full again. After getting some help from someone, I found that Skype, despite being uninstalled, was still running in the background, and found that there were residual files. The residual stuff running in the background was trying to communicate with what I had uninstalled, and logged multiple errors per second in a plaintext file that ended up being 176GB.
Whether I did something wrong or if there was something up with the snap, I still don't know as this was over a year ago and I was still learning the ropes of Linux at the time.
- Least broken snap
- I agree in blaming Snap for that 😂 good ol apt would have done a better job, I guess.
  
  I had this problem before as well. Something was spamming log messages and filled up the boot drive. No snap needed.
- I would blame Skype itself for being a corporate-owned closed-source flaming pit of doom in this case, not your actions or the snap.

Many many years ago I wanted to clean up my freshly installed Slackware system by removing old files.
find / -mtime +30 -exec rm -f {}
Bad idea.

Not me, but one I saw... dude used chmod to lock down permissions across the board... including root... including the chmod command.
"What do I do?"
🤔
"Re-install?"
- You could boot on an USB, mount the filesystem and change the permissions. But if the dude changed a whole lot of permissions, reinstalling might be the smart thing to do...
  
  Changed it all to 000. ಠ⁠_⁠ಠ
  https://stackoverflow.com/questions/5593752/who-can-access-a-file-with-octal-permissions-000-on-linux-unix
- Yeah, a very unfortunate one: probably, the most painful to recover from. I'd just reinstall, honesty 😅 At least with mine I could simply add the necessary stuff from chroot or pacstrap and not spend a metric ton of time tracking all the files with incorrect permissions
- There's got to be other tools though that could change the file permissions on chmod, right? Though I suppose you'd need permission to use them and/or download them.
  
  You can dump the permissions from the working system and restore them. Quite useful when working with archives that don't support those attributes or when you run random stuff from the web 😁
- I managed to do that back when I was new. Luckily it was a fresh install, so I didn't lose much when I had to reinstall.
  So far, that has been the only time I really screwed something up outside of a virtual machine.
- oh... uh...
- @jordanlund @fl42v I think this one could be recoverable if they had a terminal still active by using the dynamic loader to call chmod — or by booting from a liveCD and chmodding from there.
  That'd likely get you to a 'working' state quickly, but it'd take forever to get back to a 'sane' state with correct permissions on everything.
  
  Exactly. There's no way to even know what the previous permissions were for everything.
  They were TRYING to recursively change permissions in a single directory, accidentally hit the whole system. :(

Tried to convert Ubuntu to Debian by replacing the repos in sources.list and apt dist-upgrading. 💣 Teenagers...
- I thought about trying something like this the other day and quickly reconsidered
- I'm as nerdy as they come, but... I don't think you did teenage rebellion right.

One that I can remember many years ago, classic trying to do something on a flash drive and dd my main hdd instead.
Funny thing, since this was a 5400rpm and noticed relatively quick (say 1-2 minutes), I could ctrl-c the dd, make a backup of most of my personal files (being very careful not to reboot) and after that I could safely reformat and reinstall.
To this day it amazes me how linux managed to not crash with a half broken root file system (I mean, sure, things were crashing right and left, but given the situation, having enough to back up most things was like magic)
- Many years ago I was dual booting Linux and Windows XP. I was having issues with the Linux install, and decided to just reinstall. It wasn't giving me the option to reinstall fresh, only to modify the existing install.
  So I had the bright idea to just rm -rf /
  Surely it'll let me do a fresh Linux install then.
  Immediately after hitting enter I realized that my Windows partitions would be mounted. I did clearly the only sensible thing and pulled the plug.
  I think I recovered all of my files. Kind of. I only lost all the file paths and file names. There was plenty to recover if I just sorted though 00000000.file, 00000001.file, 00000002.file, etc. Was 00000004.file going to be a Word document or a binary from system32 directory? Your guess is as good as mine!

sudo rm -f /lib /usr/share/backup/blah blah.tar.gz
Note the space.
- Oh man, you really owned those libs
  
  You need to use chown if you want to own the libs
  
  Note the past tense
- Might be recoverable if you had a live distro ready. Otherwise, o7.
  
  Oh no, this was back in the days when we loaded our distros by way of a stack of floppy disks.
- Top tip, if tired, replace the rm -f part of the command with something innocuous for a first run. Actually, is better to do this mistake once so that the two important lessons are learned... Backup (obviously, in your case it was backups, but the point still stands) and double check your command if it has potential for destruction 👍
- spaces in rm are a classic one, they're even mentioned in the Unix-haters handbook

First, the classical typo in a bash script:
set FOLDER=/some/folder
rm -rf ${FODLER}/
which is why I like to add a set -u at the begining of a script.
The second one is not with a Linux box but a mainframe running AIX:
If on Linux killall java kills all java processes, on AIX it just ignore the arguments and kill all processes that the user can kill. Adios the CICS region 😬 (on the test env. thankfully)
- If on Linux killall java kills all java processes, on AIX it just ignore the arguments and kill all processes that the user can kill.
  jfc, is ignoring arguments the intended behavior?
  
  On a real UNIX (not only AiX) killall is part of the shutdown process - it gets called by init at that stage when you want to kill everything left before reboot/shutdown.
  Linux is pretty unique in using that for something else.
  
  Yes: same command name, two different semantics:
  AIX man page
  The Linux one
  Cross-Unix scripting is fun ☺️
- Wow, the last one is quite unexpected. What a useful command
- after reading what "set -u" does, bro this should be default behavior, wtf?

I thoroughly backup up my slow nvme before installing a new faster one. I actually didn't even want to reuse the installation, just the files at /home.
So I mounted it at /mnt/backupnvme0n1, 2, etc and rsynced
The first few dry runs showed a lot of data was redundant, so I geniously thought "wow I should delete some of these". And that's when I did a classic sudo rm -rf in the /mnt root folder instead of /mnt/dirthathadthoseredundantfiles

I can't even remember how I did this, but overwriting the partition table on the main production server at our small startup (back when "the server" would usually live on the premises of the startup). I remember my boss starting to hyperventilate from panic while I reconstructed it from memory / notes, and all the filesystems came back and he calmed down.
Same job, they gave me a little embedded-systems unit for me to use to build a prototype on. I hooked it up, nothing worked. I brought it back to them.
Hey, this one doesn't work.
Huh... that's weird, it was working before. Did you break it?
I don't think so. Can I have one that works?
They literally told me, as they were handing me the second one: Okay, here's another one. Don't break it.
I figured it out literally seconds after breaking the second one... I was hooking it up to 12 volts of power when it needed 5. Second dead computer. Explaining that and that I needed a third one now was fun.

CTRL-C-ing apt because it looked stuck for more than 10 minutes. I don't recommend doing it.
- Man, gotta love apt sometimes
  
  apt is great, but yeah, if it's gonna fail, let it fail on its own.
- Haven't used apt in a while, is it not atomic? What happens if you mess with it?
  
  I don't think it is, if it doesn't run its course on its own, you're screwed. It's Debian so you can recover, but, at least for me, it was painful.

Not quite catastrophic but:
I'm in the process of switching my main server over from windows to Linux
I went with Deb 12 and it all works smoothly but I don't have enough room to back up data to change the drive formats so they're still NTFS. I was looking at my main media HDD and thought "oh, I'll at least delete those windows partitions and leave the main partition intact."
I found out the hard way that NTFS partitions can't just reclaim space like that. It shuffles all the data when you change the partition. It's currently 23 hours into the job and it's 33% done.
I did this to reclaim 30 MB of space on a 14 TB drive.
- You mean you've removed the service partitions used by windows and grown the main one into the freed space? Than yes, it's not the way. 'Cause creating a new partition instead of growing the existing one shouldn't have touched the latter at all :/
  
  Yes, I grew the existing one. Lesson learned I guess. 30.5 hours into it and it's at 41%.

Tinkering is all fun and games, until it’s 4 am, your vision is blurry, and thinking straight becomes a non-option, or perhaps you just get overly confident, type something and press enter before considering the consequences of the command you’re about to execute… And then all you have is a kernel panic and one thought bouncing in your head: “damn, what did I expect to happen?”.
Nah, that's when the fun really starts! ;)
The package refused to either work or install complaining that the version of glibc was incorrect… So, I installed glibc from Debian’s repos.
:D That one is a classic. Most distributions don't include packagers from other distros because 99% of the time it's a bad idea. But with Arch you can do whatever you want, of course
My two things:
I've heard about some new coreutils (rm, cp, cat... this time the name really fits the contents :D) and I decided to test it out. Of course it was conflicting with my current coreutils package and I couldn't just replace it because deleting the old package would break requirements. So without thinking I forced the package manager to delete it "I'll install a new one in just a second". Turns out it's hard to install a package without cp, etc :D
I don't remember what I was doing but I overwrote the first bytes of hdd. Meaning my partition table disappeared. Nothing could be mounted, no partitions found. Seemingly a brick.
Turns out, if you run a rescue iso, ask it to try and recognize partitions and recreate the table without formatting, Linux will come back to life as if nothing happened
- Nah, that's when the fun really starts! ;)
  Well, on the upside, it definitely works better than coffee or energy drinks :D
  Also, nice save with the last one!
  
  Funny, that's when I give up for the night and go to sleep

Before installing Arch on a USB flash drive, I disabled ext4 journaling in order to reduce disk reads and writes, being fully aware of the implications (file corruption after unexpected power loss). I was confident that I would never have to pull the plug or the drive without issuing a normal shutdown first. Unfortunately, there was one possibility I hadn't considered: sometimes, there's that one service preventing your PC from turning off, and at that stage there's no way to kill it (besides waiting for systemd to time out, but I was impatient).
So I pulled the plug. The system booted fine, but was missing some binaries. Unfortunately, I couldn't use pacman to restore them because some of the files it relied on were also destroyed.
This was not the last time I went through this. Luckily I've learned my lesson by now

First time trying Linux I went with an arch install because I Googled "best version of Linux" and went with arch. Followed a guide to the point of drive formatting and I decided to go with a setup with drive encryption. I didn't understand what I was doing, ended up locking myself out of my hard drives and couldn't get windows to reinstall on them. I used a MacBook for a week until I installed Ubuntu and managed to wipe and reset my drives and reinstalled. Needless to say I am going to read up a little more before I try that again.
- Been there, and even without encryption: took me to reinstall a few times before I realized I can chroot again and repair 😅
- Archinstall python script is your friend 😄😉 I tried install arch manually, but as I learned that not even sudo is included in the Linux essential packages, I stopped the process and went back to aromatic script install, lol, got no time for that S*** 😂

fstab bind mount for /home that I misspelled, so I couldn't login as myself.
fstab external hdd mount that didn't have ignore flag so PC would pop if I booted while unplugged
Accidentally booting windows after a year and it overwrite my EFI boot entry.
The best I've see however was an acquaintance who accidentally set perms to own user on /usr/bin
So everything went from root:root to user:user which removed all the SUID/SGID bits as well so a bunch of bins broke lol.
Believe it or not, it was actually fairly easy to fix with chmod and chown
- I have an embedded device that runs as root and has busy box. I accidentally ran chmod -x on one of the busy box sym links (strings I think) and it made all of the core utils un-executable. Unfortunately chmod is a core util. Every bash command was throwing wild errors and outputing gobbledyremoved. You really start to sweat when ls and cat stop working.
  I had full disk image of the device and started deducing the issue. Luckily I could still execute non core utils and ssh/scp was working so I wrote a little program to restore permissions, uploaded/ran the binary, and learned nothing from the experience.
- Had the issue with the ignore flag missing literally a week ago. I mounted the HDD to troubleshoot it, ended up kicking the bucket, couldn't read any partitions from it anymore, but I had the Partuuid in fstab. Had to plug the main drive of the system into another one to fix fstab....

Found out the hard way that if you edit /etc/sudoers with anything other than visudo you best be absolutely sure the syntax is correct, otherwise sudo will refuse to read it and you'll be locked out.
Also learned to add -rf to the rm command at the end, after I re-read it to make sure it does what it should do. Something like rm /path -rf instead of rm -fr /path. That protects you from your fat fingers hitting the enter key half way through.
- Been there with sudo. Fortunately, su still works, as well as going to another tty and logging in as root. Well, as long as the root login is enabled; otherwise that old hack with init=/bin/bash may work, unless you've prohibited editing kernel cmdline in the boitloader or decided on efistub
  
  IIRC the root account was disabled (with no password), so I resorted to my trusty SystemRescueCD pen to fix things. Never leave home without it.

stupid was when I wanted to test Linux Mint on an external SSD, and didn't check that the bootloader wasn't going to overwrite my internal drive's.
So anyway I'm running Linux Mint now.
- That's an interesting way to distro hop for sure
- It's a fine distribution. I have it on my desktop and at least one laptop. But yes, a weird way to decide to distro hop 🤣
  
  I was on Manjaro, and I didn't want to put the effort in for a third time just to break it again. While I prefer arch based distros, I've been liking Mint since I can almost use it without a terminal like manjaro.

I uninstalled Python.
I was playing around with Pygame of all things, and it wasn't behaving as the (apparently out of date) documentation was saying it should, so I figured I'd just uninstall and reinstall Python.
EVERYTHING borked. APT wouldn't even work.
- Oh that's a good one. It feels like it should be doable and then.... BAM
- Ha! Came to say this too!
  I tried to uninstall Python because I was just trying to minimize junk on my computer and I usually code in Bash, Node or Java.

Years ago I was dual-booting with Ubuntu just to try out whatever this Linux thing was that all the nerds were talking about. Liked it and played around with it, but for whatever reason I wanted to go back to just Windows, I needed the space I had partitioned off or something, can’t remember why. So I just uninstalled or deleted the bootloader somehow (maybe I just deleted the Linux partition and expected the space to clear up like normal).
Go to restart the computer… oh shit. Ohshotohshitohshitohshit.

Deleted my entire efi partition while trying to install some grub themes.
And then my backup didn't work when I tried to restore it.
I have pretty colours now though, so it was all worth it :)
- Been there, done that. But I haven't had any problems once I switched to systemd-boot 🤷
- 😁

I've done my plenty of stupid stuff, from dd disks I was using to forcefully uninstall dependencies of the package manager. But the one that takes the cake for me happened back in 2012, I was working at a research lab in the university and was sharing a computer with another intern. That other intern used Gentoo and so we agreed that the machine should be Gentoo, I've installed it at my house on my PC and got comfortable with it before we shared that computer. One thing that I learnt when installing Gentoo is that the /dev folder is created on boot, you don't populate it when installing, instead you mount the one from the host system you're using to install.
The computer had an issue with a device, can't even remember what it was, so I thought I'll run rm -rf /dev that should take care of the issue and after a reboot it will be repopulated... It might have worked, but what I actually ran was rm -rf /etc.

Just straight up overwriting boot sector and superblock of my hard drive thinking it's the USB drive.
Udev tried to warn me, saying there's no permission, and I just typed sudo without thinking.
Then after a second I remembered USB block devices are usually writable by users, but it was too late.
- USB block devices containing mountable filesystems (on Desktop systems) can generally have those filesystems mounted and files written to them by regular users; But the block device itself stays only root writeable.
  So, you need root privileges either way.
  (Going from memory, but also decently confident)

I don't know if that counts, but on a fresh default Debian Stable system, my cat walked across the keyboard and the DE crashed.
I could still switch to another TTY and reboot via command line.
After the reboot, I was greeted by a blinking cursor and nothing else. Had to reinstall.
- keyboard cat strikes again
- Cat killed grafic card driver?

My own classic was fiddling with the nvidia PRIME config to try and get rid of some very mildly irritating screen tearing. No graphics output at all. Now this is fixable of course, but it's a pig.
And I'd decided to do this 2 hours before an incredibly important progress review meeting for my PhD.
Got it back with about 10 mins to spare and decided just to leave the driver config alone after that.
Bonus round
Also a friend managed to bork his ubuntu 16 laptop by trying to switch from unity to gnome and ending up with sort of neither. That was reinstall territory right there.

Somehow convinced a person to run sudo chmod -x /usr/bin/*
I don't remember the exact command so it could be a bit different but it did the job. It was a fun evening.
- The first time I read this, i thought "shouldn't all that be executable anyway?"
  And then I read it again and realized, minus x
- An intern nuked their workstation by sudo chmod -R 777 /. Turns out adding exec to everything isn't good either.
- Daaem, I guess the poor dude at the receiving end did not consider it particularly fun. Well, at least they had sbin working, so probably possible to recover without a live cd. Huh, guess who's now spinning up a VM to check it out 🤣
  Checked it out: on arch that results in inability to run tty on reboot, then you're dropped into initramfs's rescue shell where you can simply +x new_root's /usr/bin/* and be back up and running

Backed up the whole disk image to an external drive because I didn't have time for a proper backup but knew I would need some of those files later.
Installed a fresh new OS on the same disk, used it for a couple of months.
Needed to make some space on the external drive I had the backup on so I'll just delete the backed up system files from it.
cd /mnt/external_drive
rm - r /usr /boot ...
As you can probably see, a fresh new install was happening again
- Took me a solid second to get it as well.
- ☠️

I wanted to use fio to benchmark my root drive. I had seen a tutorial saying that the file= parameter should point to the device file, so I pointed it at /dev/sda. As you might expect, the write test didn't go so well.

Learned about the importance of trailing slashes in rsync by using the -delete flag.

This was pre-linux for me but something you can still do in most distros so I think it's a valid story.
In 1999 I was using Napster on computer running MS-DOS. I was 12 years old and an aspiring open media enthusiast/stupid script kiddie. I was using the file explorer interface in Napster and accidentally gave access to my entire C drive. I also had opened ports to share certain media and to fuck with my friends using daemon tools (back then you could do stupid stuff like control a friend's desktop with certain versions of daemon tools). Immediately I started receiving packages called things like "sleep.tight.tiny.mite" and I knew I was fucked so I clicked in the Napster interface and clicked "delete" and deleted my entire active drive.
I panicked and installed the only operating system we had which was a random copy of Red Hat. When my dad came home I pretended like it had always had Linux on it. I do think he was more impressed than mad.
- "Just pretend it's always been Linux" is a bold move. I salute 12-year-old you o7

I have a stupid one, but far from funny.. I've been using and building computers for a very long time so I'm far from a noob, but I'm still quite cautious, bordering on paranoid, so I like to unplug all other drives when re/installing an OS just to avoid stupid mistakes. I go through the installer on the livecd, there's only one drive to choose from so I don't think much about it, select that it should erase everything, I set up the new partition structure, and start the process. After about a minute I begin wondering "why is it taking so long?", and "what is that ticking noise? SSDs shouldn't be making any sounds when written to", when I realize that I had unplugged the wrong drives and that I was currently overwriting my main storage drive. Of course I had backups of the most important things like photos and code, though not really synced for a couple of months so I lost some stuff permanently.
- I can totally feel that sudden clot in the gut the moment you realize on which drive the action is happening, just by reading this.

I deleted bash on my work computer one week into the job 🫠
- csh FTW eh 🤣

I copied a program into the /bin/ folder while in a file browser with sudo permissions and somehow overwrote every file except the one I was moving. It, of course, couldn't boot, but copying the bins from a live iso made it at least boot able. Reinstalled Linux after that, of course.

I've broken systems far too many times in the last 24 years, since Mandrake 6.x, to count:
I've dd a disk or more
I've rm *
I've chmod
I've brought down the network, with every intention tar it would come back - on a remote box
I've failed to RTFM far too many times

Nooo I have so many.. This one I can explain in English:
Xubuntu but blind
So, this is ~2016. Ubuntu is hip and a handful of my students use it. On my PCs I only use Debian and Suse. So to help them better I take out an old ASUS laptop and install Ubuntu on it. Try out Xubuntu instead.
At that time I was also huge into alternative keyboard layouts. I had a slightly modified Neo keyboard layout installed when I switched to Xubuntu.
Here the fun starts because the obscure internal graphics card built into the laptop didn't have driver support under Xubuntu. Black screen but I could hear it working. This was the hardest driver fix I ever did. No monitor and a keyboard layout I wasn't used to, under a Linux distro I wasn't used to. And I also was at the university library, so no hardware support or Debian stick in reach.
- How did you do it with no monitor?
  
  I did have a smartphone, so I was able to look up several steps I could try. For example installing an experimental driver. In the end I had to install kubuntu and purge xfce, since they had a working driver in their library.
  Since I had to type in all commands blindly the worst part was obviously wondering if I mistyped somewhere or if it just didn't work. When I lost track I used the beep command to check if I was stuck.

Not the installation strictly speaking, but my most "funny" fuckup was setting up xfree86. There was a configuration for crt monitor scan frequency that you had to setup. I messed up something and the monitor started to squeel like crazy and quickly hit hard reset in panic.
The monitor didn't die, but it had a slight high pitch noise to it after.
- Back then I was testing modelines to see the maximum I could push to my 14" monitor. I then backed it with a 1200x1600 virtual screen.
  My girlfriend got sick from watching me scrolling around and bought me a 19" display which could do that resolution - and ended up frustrated when I added a larger virtual screen.
  
  A 19" monitor was quite big for the day, and expensive! I hope your gf didn't beat you up too much for that :)
- I know little about crt because I was born in 2000. Can you explain why did the monitor started to make scary sounds?
  I know that crt monitors didn't have any method to report the supported frequency, aside from more recent models, correct?
  
  Yeah, monitors were somewhat dumb, just received and did what the vga output asked to do.
  The noise most likely came from the semiconductors that controlled the magnet field that directed the rays onto the screen. These components are selected for a specific speed that the monitor can handle. So going under or over it's spec can make something resonate in the audible range, and could even destroy the components if stressed too much.
  The thing is that for each resolution and refresh rate you had two values to configure, one for the vertical speed in Hz, and horizontal speed in kHz. These values were usually specified in the owners manual. Typos can happen, and this was quite a risky operation.
  
  A good starting point for a wikipedia rabbit hole covering the software aspects on how to drive a display: https://en.wikipedia.org/wiki/XFree86_Modeline

Connect via ssh to my home server from work
Using a cli torrent client to download stuff
Decide I need a VPN.
Install VPN again from CLI
Run VPN which disconnects my ssh connection
Even when I get home, the server is headless so I have to locate a keyboard and mouse before I can fix.
- Same.
- Dang, similar stuff happened to me on nixos. Had to instruct one of the relatives on how to reboot the machine and choose a previous generation in the boitloader 🤣

Not strictly Linux related, but in college I was an IT assistant. One day I was given a stack of drives to run through dariks boot and nuke.
I don't remember exactly what happened, but I think midway through, my laptop shut off.
Guess who picked the wrong drive to wipe with DBAN :)

Oh, i have a brilliant one:
A few years ago i spent a lot of time converting .flac-files into .ogg-files in order to put on my oldschool iPod. As I did a lot of repetitive typing - entering $dir / for file in flac ; do convert etc / mkdir -p $somewhere/$artist/$album / mv $somewhere/.ogg->$new_dir/ and so on - I thought: "hm lets just write a loop over loops for all the artists here and then all the albums and at the same time create the nested directories somewhere else... hm actually in the home directory.... and later love everything on the iPod at once."
so i was in my music folder with the artists-folders i wanted to convert. i did something wrong
So i did my complicated script directly in the shell. I made something wrong and instead of creating a folder "_{/artist/album" I created 3 folders in my current working directory: "}", "artist" and "album". hmph dammit gotta try again... but first : i have to clean up these useless folders in the current dir. so i type of course this: "$ rm -r ~ artist album " after about 5 seconds of wondering why it took so long i realized my error. o_O I stopped the running command, but it was (of course) too late and i bricked my current installation. All the half-deleted config files made or impossible to start normally and extremely tedious to repair it by hand, so i reinstalled.

Generated my grub configuration as grub.conf
This one took a stupid amount of time to debug - but on the other hand, when grub failed it did with "can't find any bootable thingy" and not "missing configuration file" as, in my later opinion, it should.
~~Life~~ Linux is a harsh mistresses, sometimes.

Oh, I just remembered another one or three. So, resizing the partitions. My install at the time had a swap partition that I didn't need anymore. Should be simple, right? Remove the partition and the corresponding fstab entry, resize root, profit. Well, the superblock disagreed. Fortunately, I was lucky enough to be able to re-create the scheme as it was, and then take my time to read the wiki and do the procedure properly (e2fsck, resize2fs and all that stuff).
Some people I've met since, unfortunately, weren't so lucky (as far as I remember, both tried to shrink and were past mkfs already) and had to reinstall. The moral is, one does simply mess with superblocks; read the wiki first!

On OpenSUSE, in Yast bootloader tool, there is a checkbox to to do something like locking the bootloader (it has been a while, I don't remember the exact thingy). Rebooted and oh, surprise, the bootloader was locked... Which mean Grub didn't load.
I had to reinstall the whole OS 🤣

Writing and running a script to delete the first 2 characters from all files and folders recursively.
It started backtracking to my home folder. :/
- at's a funny story, hope you got everything backed up

Linux Mint: removed all taskbars from the desktop. I was hoping it would just allow me to reset them to the default. But in reality, it breaks the GUI and it's very hard to reset from the GUI. Suddenly my keystrokes weren't being detected and I couldn't open up applications with any sort of regularity. After a lot of dicking around, I got the terminal working so I could reset Cinnamon.
It's not the worst way I've broken a machine. But it was one of the most annoying.
- One thing I learnt a while back is that if you break your GUI you can always use Ctrl+Alt+F<1-9> to go to different terminals to try to solve it. Worst case scenario I would do something like mv .config .config.bkp and sudo systemctl restart that should hopefully get you back to default settings on the UI.
  Source: been there, done that. Not exactly your error but similar enough.
- Always remember, there is always a "terminal" accessible: Don’t forget poor tty

I once deleted the network system in alpine. I'd been having some trouble with with the default one (I think wpa_supplicant) so I decided to try the other one (I think iwctl). But I thought that there might be problems with havung both of them so before I installed iwctl I deleted wpa_supplicant (thinking that it was more of a config utility than the whole network system), only to find that I couldn't connect to the internet to install iwctl.
- You could have used the netplan yaml file 😇 or chroot from live distro

Types
rm -r -f Presses strg+v (instead of strg + shift + v)
Hits enter
Maschine proceeds to delete the home folder as the garbage that comes when pressing normal strg+v gets interpreted so...

Let's see: Unintentionally making a proxy accessible to anyone online
Accidentally deallocating an ext4 partition and then having to run testdisk on it
Trying to manually create a grub entry and corrupting the bootloader
Installing a arch derivertive and having it silently overwrite grub
Installing puppy Linux and then trying to get it to use apt
Incorrect use of ppa's on mint resulting in very old packages being installed
And many others besides
- The first time I enabled o auth for something self hosted, I gave access to anyone with a Gmail account.

Installed python3 before it was made the native python on the dist. Half broke everything, including apt & python. So I uninstalled it, and then everything was broken. Finally got python3 reinstalled, and lived with it kindof working & awful distribution updates.
I have finally freed myself of that prison last month, by nuking everything and starting fresh.
- You can have both python 2 and 3 on the system. It just depends upon which is the default as to how much you break it 👍 The symlink to /usr/bin/python is the important bit for most software. For deb-based at least, update-alternative is your friend.
  
  I'll happily say I must have overlooked something, but I did try using update-alternatives. I don't remember all the nuts and bolts from the start, but it involves python3 and distribution upgrades. I spent a good number of nights over the years trying to unmess it up, and am happy to never think about it ever again.

I set up 2FA via a hardware security key (a yubikey) for login, sudo etc. I then tried to switch security keys, removing the old pam files and adding a new one. But I didn't tidy the pam files up before logging in, and there was effectively no way to log in, since editing the pam files required sudo access to edit in the first place. So basically the whole system required access to a pluggable authentication module that it no longer had any ability to recognize. It was honestly pretty funny. I did manage to recover my data by booting from a live system and decrypting my drive from there.
I've also accidentally removed my desktop environment twice while trying to update Python versions and then cleaning up old packages, but that's kinda not that big deal and is just a facepalm moment.

sudo apt autoremove
Who ever made this shit and then decided to always show you this message that you should do it. What a dick

I didnt break anything, but there was this one time i was setting up a new lxc container i had just spun up. I installed nginx, and a bunch of other packages, started writing new config files.... Then i noticed my prompt was user@desktop$ instead of user@server$
Whoops... I was in the wrong terminal window, typing commands into my desktop instead of the container i was setting up.

sudo apt remove python3
Thinking I would install a more recent version. 😂
- Classic

Don't get me started.
There are good reasons why I have personal "production system" to do my work with.

Years ago a friend mistakenly typed in killall5 as root on a remote server. Didn't break things but resulted in extra work and effort.

One day on my main Arch installation I created a container inside a directory, and "booted" into it by using systemd-nspawn. When I was done with it I decided to do a rm -rf / inside the container just to be funny. Then I noticed that my DE on the host froze and I couldn't do anything. Then I realized that systemd-nspawn mounts some important host's directories on the container, and I deleted those when I did the rm -rf /. I didn't lose anything, but it was scary.