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First_Slide3870@reddit

I deleted /etc/passwd , I was on a plane, no internet at the time. Only had a RHCSA cert guide to help me figure it out, took \~2 hours to get everything up and running again.

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hectoralpha@reddit

haha, what is the solution there ? aside from reinstall

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S4LTYSgt@reddit

I sudo’d and erased all the logs from var log by accident. It was a pagerduty alert at 3 am. I was already hammered and yea… but at least I didnt bring down production lol

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after spending weeks learning and setting up a qmail toaster, Bind apache with php, mostly compiled from source on slackware because I'm a madman, I accidentally spacebared a / at the end of a chown apache:apache -R /var/www/home /

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Powerful-Cost-8387@reddit

Similar accident. Except I ran "sudo rm -rf / home/user/folder1". By the time I hit Ctrl+C, it had already made it to /proc.

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One_Target2740@reddit

So does that make both the WordPress directory and the whole system an Apache reservation?

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destr0yr@reddit

The whole system was assigned apache:apache. Everything! System binaries config files. Everything. It resulted in a nuke & pave.

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TheGreatNico@reddit

Trying to install ubuntu Hoary Hedgehog beta on my poor, abused Dell Dimension desktop. Never did get it to work.
Next big series of oopsies was thinking the code I wrote for a college class that needed to run on the mainframe, that I could just write and test it on my linux desktop. Nope.
Then there was the time I screwed up the firewall rules and exposed port 22 to the Wan. 500k attempted logins in a week. Learned more about firewall rules and routing, and what fail2ban is, from that.
Enabled SELinux in 'enforcing' on my only working computer that had been through a dozen different distros since its last full wipe/OS drive failure. That took a long time to relabel and learn how to use audit2allow, what selinux contexts were, and about linux permissions full stop.
I make all my screwups on my personal systems so that by the time I need to try putting something on the work network, while I may not know what to do, I do have an idea of what not to do

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jpirog@reddit

Back in ~2000 when we had a family computer, I installed Linux. Little did I know, I wiped all the things to get it installed. That was my first mistake.

I made many more.

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Alarming_Jicama_2608@reddit

How old were you? Were your parents understanding?

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jpirog@reddit

11 or 12, yeah they were understanding. No beatings this time lol

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kuzared@reddit

I remember I was so paranoid installing Linux alongside Windows back around 2004 or so, fearing I’d mess everything up.

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jerryxlol@reddit

rsync for whole laptop when mounted company storage ... snapshot on the storage saved my ass :D

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tecedu@reddit

yum upgrade while trying to install latest version of docker; made the entire system unbootable due to conflicting gcc libs? Managed to fix it but after that realised how much good long term releases are

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zAuspiciousApricot@reddit

Accidentally copied command with the “>” essentially overwriting/deleting an important file in production

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CraftyPancake@reddit

Spent too much time customising everything

There’s something to be said for just sticking to the defaults

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yournicknamehere@reddit

I feel that. I can't count how many times I wanted change GRUB background image and order on GRUB list (while having Windows installed alongside Linux) and ended up with no background and no option to boot to the linux.

Since then I'm installing linux always on different disk instead partition on the same disk.

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kieppie@reddit

rm -Rf . /

dd to disk rather than file or partition

loads of fat-finger mistakes

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SirZer0th@reddit

Isn’t that the command for „receive mail really fast“? scnr

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JaschaE@reddit

You have told people that Alt+F4 opens the Settings in an online game at least once in your life didn't you?

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SirZer0th@reddit

Maybe like 25 years ago ;) but iirc this is an old admin joke from the 80s, oder 90s?

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JaschaE@reddit

Old and a joke in any case. Onlinegames/groupchats "Noob asks 'How do I X?'" "Just Alt+F4 and it's in the menu..." *disconnect*

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Lucky__Flamingo@reddit

I misunderstood how symlinks interact with find and cd.

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Altusbc@reddit

On a production server I overwrote /etc/fstab which had quite a few custom mounts, with a generic version of the file. Mistake was not noticed for a couple of days until the server was rebooted and did not load at all. Took a bit of beating on that, and then it was firmly instilled into me by my manager, the importance of creating a backup of files before editing etc.

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Duck_Diddler@reddit

At work? Not saving commands/scripts that use weekly.

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Advanced_Vehicle_636@reddit

A buddy of mine got tired of running "sudo su -" every time they logged in. They set all files on the VM to be owned by their user with global read/write/execute. It went about as well as you can imagine. Thankfully, I'm not an idiot and had given his VM two disks. One for the OS (128GB) and one for his storage (5TB). The data was safe. The VM?> Not so much. I torched it and rebuilt it.

In terms of my biggest mistake though? I grew up on Linux to some extent. It was my first OS (Ubuntu) for my first owned PC. Probably did lots of dumb shit on it by mistake. I haven't made a lot of Linux mistakes professionally... the only one that comes to mind is a former linux VM I had that wasn't in HA (critical though) and ran a database locally with no backups. For reasons that remain unknown to Microsoft and I to this day, the VM tried to transition to Gen 2 but was actually a Gen 1 image. Destroyed the ability for it to boot. Switching the VMs between G1 and G2 wasn't helping.

Eventually loaded the disk into a nested Hyper-V server in Azure, recovered the database through a rescue linux environment, and then immediately migrated the whole thing to a new (upgraded) server. Spent several hours trying to manually fix everything. The old DB version wasn't available anymore which made the process of upgrading the DB a pain in the ass. It may have taken several hours, but I did eventually get it all running again.

Then I put in a replacement with a separate DB because no way was I going through that fresh hell again. I put in HA while I was at it because having only one of them was a bad idea anyways.

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InGordWeTrust@reddit

I deleted my hard drive. But I was able to recreate it by giving it the exact same specs. It found all the files.

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Capt91@reddit

Routed myself out of connectivity via an iptables rule.

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Kripthmaul@reddit

Man, that snapper folder is taking a lot of space...i'll just rm some of them. Some time later, wonder why cat is not working anymore, some more time later, hm why can't I rm anything anymore...

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Tall-Introduction414@reddit

Tried to install Slackware on my best friend's machine, and accidentally overwrote his DOS partition in the process, and thus all of his files. Granted, this was like 1995, but... lesson learned: Pay very close attention to which partitions you're writing to.

He was really pissed off at me and swore off Linux for a few years.

Installing downloaded .deb files. Just... don't. On that note, pulling a Linus Tech Tips and hosing my system by not reading closely the output of apt before typing "y."

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REO_Jerkwagon@reddit

I've tried to describe Slackware to some of my colleagues who weren't alive yet when I was using it. No package manager (at the time, maybe later?), compile your own kernel, X11 was a nightmare... but you got to run a cool chat app named BitchX and that made it all worth it.

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errl0g@reddit

rm -rf /*

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DisplacerBeastMode@reddit

I once removed all the logs in an entire environment.. yeah that sucked

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Oh_for_fuck_sakes@reddit

I did the same. Except it was on the hypervisor. And it was actually every thing. Thankfully only in a test environment!

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SXKHQSHF@reddit

There was a story around 2012 about a startup networked storage company 2 months from product launch where the founder stayed late over Saturday night and decided they needed some cleanup... And with a single command deleted the entire company.

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SXKHQSHF@reddit

I saw this done in a roundabout way...

I spent some time doing software QA for a company with a large UNIX infrastructure, all in remote locations. Each site had a low end server (in truth, a high end desktop) plus multiple external chassis providing various services. Software updates and changes were delivered in a bundle with a shell script to install. While this was not Linux, package managers like RPM were not yet around.

The dev group that handled the server side of the code had deep UNIX experience. The microcode group did not.

We'd had a problem for a while with disk space exhaustion. Everyone did their own package accept. Some did not bother cleaning up temporary files. So management decreed that all would use a common script template. A good idea. The decree included an aggressive timeline. A bad idea.

The new script included several standardized variables, including two lines

Set TmpDir to the directory where installation files are stored

TmpDir=""

And the last command in the post install cleanup routine was

rm -rf /${TmpDir}

This worked pretty well, until 6 months down the road. The microcode group issued a package that was a configuration change only. No code was downloaded. The value of TmpDir was "".

So when it was installed on the first QA server, the cleanup routine executed rm -rf /

There was a request for a quick turnaround so my colleague had already moved to the second QA server before I diagnosed the problem. They were about to start on the third... Luckily we only had to reimage two

Mistakes: No default value set for TmpDir. Cleanup routine did not validate TmpDir before executing. QA and all developers did not sit down for a table read of the standardized script before pushing it into production.

And yes, experience like this has always made me leery of Agile.

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RumRogerz@reddit

gif

beat me to it

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InternationalEgg5330@reddit

We all did it at least once. Purposefully or not.

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theindomitablefred@reddit

Not sysadmin related but I installed Linux on my second hard drive with the Windows drive still installed and the Windows boot option disappeared, so definitely remove any other hard drives during install if you're dual booting.

I'm not sure how far along you are in the learning process, but LabEx has some courseware that might be helpful including sysadmin command line, cybersecurity, etc.

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Jamesmoltres@reddit

Installing it.

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landob@reddit

My first mistake with linux was starting with Gentoo as my first distribution.

I'm not exactly sure why I chose it, but yeah I never got the thing off the ground and eventually tried Mandrake/Mandriva and that got me my start.

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LxckyFox@reddit

How was gentoo for you? When i switched from windows to gentoo i tried unmasking plasma 6 and that's what fucked me up. I eventually switched to arch and then into gentoo again and I'm pretty happy with my gentoo install right now

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landob@reddit

Don't remember. This was like 25 years ago lol.

I just remember trying to get it going and somewhere along the way in documentation read that you essentially have to compile it yourself. I struggled with that whole process. This was probably circa 2002. I had just got my computer for graduation in 99.

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Vaultgoblin64@reddit

gentoo hiring here, do you mind coming back to us ?

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Ssakaa@reddit

I miss Mandrake... that had a better, more coherent, more consistent, and more complete settings UI than Win11. Desktop Linux's gone drastically downhill since. Found it after trying slackware and not remembering what I'd set as the root password during the install... then eventually went back to Slack, and worked my way up to LFS for my next few builds. That made the later switch to Gentoo far easier...

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e_t_@reddit

Initially, I had to pkill vim from another terminal because I didn't know how to exit.

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Vaultgoblin64@reddit

modern problems need modern solutions

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Ssakaa@reddit

Learned both how to get to a second terminal and find PIDs and kill them that way. Then eventually I learned how to exit...

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Alexandre_Man@reddit

Running reboot in the wrong server

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H3rbert_K0rnfeld@reddit

I stepped on the power cord of a Sun X1 pizza box server. It ran slapd. The cabling at the place was atrocious. The power outage let us discover Sun Cluster Service did work as well. Hahah!

What did we do to mitigate! I zip tied the power cable to the PSU on slapd1 and slaps2. Smdh.

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Ssakaa@reddit

Yeah... learned the value of the velcro straps on Dell PSU's one time...

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Pocket-Flapjack@reddit

I was once trying to fix a broken app,

It had /Path/to/file/usr and I wanted to remove it.

Instead of rm -rf ./usr

I did rm -rf /usr

Then wondered why the VM stopped 😂 Snapshots saved me that day

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Ssakaa@reddit

VM

Lucky... my first rm -rf blunder was the classic spacebar isolating a "/", and well before --no-preserve-root existed... and it was indeed not a VM...

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ender-_@reddit

I don't remember doing anything critical in my first 3 months of using Linux. However, a year ago (after using Linux for more than 25 years) I managed to wipe both of my home server's OS SSDs instead of just wiping a partition on each of them. I even used -f parameter to blkdiscard, so sure I was about doing the right thing.

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Greedy-Locksmith2181@reddit

Used sudo for everything instead of actually understanding permissions.

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planeturban@reddit

Not Linux, but at my first job I logged into an AIX machine, started zsh and it hanged in some way. So I logged into with another session, as root, and issued killall zsh (after making sure it was only me that ran zsh). Killall in AIX means ”kill pid 1”. So the machine halted.

So my mistake was ”not reading the man page”.

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JaschaE@reddit

Chose a common distro. I am still learning myself, but I hang out in a lot of Hacker-spaces and a surprising amount of people believe their weird fetish distro is the only true way. I had the following scene multiple times: "Hey I set up this Laptop for use with the machine." "Oh cool, thx! Starts laptop. Its gubbledidoo-OSnone of the programs our tools use have documentation for it. .tar or flatpack seem to be impossible to open anyway, documentation is non-existent because the person who set it up and the maintainer are apparently the entire user-base" Also, I expect a ring on the door any day now of somebody who wants to talk to me about our Lord&savior Nix-OS.

While lacking a cool factor, common distros, programs and solutions have the ginormous benefit of 15+ years of forum discussions to look at for answers.

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AlexMelillo@reddit

When you’re learning linux in the cloud specifically, beware of how you set up your volume mounts in /etc/fstab. Too many times volumes are mounted by not using labels or UUIDs

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powdersplash@reddit

Ctrl Alt del on a oracle server in shell out of muscle memory

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BadCorvid@reddit

rm -rf /lib/

On an AIX box that was running out of disk space...

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tuxsmouf@reddit

Typing reboot on a ssh session thinking it was my laptop. Hopefully, this server was not on linux but on Aix and there was a safety against dumbass guys like me.

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Alarmed_Discipline21@reddit

Im not a linux expert by any brand but chatgpt has been teaching me a lot lol

Not realizing that you really need to install a backup solution as many distros dont have them set up by default.
I have multiple monitors and one is a tv. I tried to set that up in a specific way (with help from chatgpt) and it caused none of my monitors to work... yeah that was annoying.
Maybe not a mistake per se but it was annoying and caused some issues. I removed one of the desktop environments I.e. Uninstaller it and messed my drivers up. Fixable? Kind of. But also kind of hard for me lol.

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colter_t@reddit

Sent Ctrl+Alt+Del to a Linux VM when I wanted to sign in. I had to for so many hosts I connected to already it just seems right…

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d0ubs@reddit

Thinking applying LVM on an existing system was nondestructive.

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Special-Damage-4798@reddit

Ran a script that change every servers hostname to hostname because I did hostname = $hostname.

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linuxprogramr@reddit

I made the mistake of executing this command logfile &> new file and it was in a continuous loop. Yeah it sucked big time

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tremens@reddit

Downed the wrong interface on a live, production, extremely critical interface - in fact the interface in which my SSH session, and ime everything else, was connected to, necessitating a series of wake up calls to speak very, very pissed off people because it would have been an 8 hour drive for me to fix.

But at least I didn't force delete the fucking root system like apparently half the comments here seems to suggest every other person in the world does the second they touch a Linux box...

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LesPaulAce@reddit

Using it. That was my first mistake. Probably around 2000. I didn’t repeat the mistake more than once or twice.

I‘ve made a long and happy career without ever having learned Linux.

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Tall-Introduction414@reddit

Terrible. Linux is the GOAT OS.

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Autoimmunity@reddit

I'll say that using Linux Desktop is not for everyone, but you also can't deny that the entire modern world runs on Linux and you're limiting your career opportunities by not knowing it.

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Extra-Hand4955@reddit

Not so much a mistake but learning. This was back when every drivers had to be complied into the kernel. I had an old 386 and I was going to the make part. It took like 30 minutes to finish so I thought that was the compiling. Took me weeks to figure out why my cdrom or sound card wasn't working.

Then I learned that I needed to compile the kernel and it took 2 hours. After that, network worked. Cdrom worked. Sound card worked. It was like a the cloud broke and heaven opened up.

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Tall-Introduction414@reddit

Oh, I remember those days. On my 386/16 it took about 24 hours to compile a kernel, and then a wing and a prayer to see if it worked.

I used Linux for an entire year (without X) before discovering that I could multitask by switching virtual consoles (alt-f1, alt-f2, etc).

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