I’m pretty sure there’s only been one time I broke my install, which was on an Ubuntu distro. This was on my old laptop, and it’s partitions are interesting because I have 1 main partition and 2 others (the first was my windows partition, before it stopped working for whatever reason and I thought it couldn’t be fixed. The second was the install that I broke).

Anyways, I remember I was trying to run some command, I can’t remember what, but I knew it kept eventually saying “Permission Denied” at some point. This was like 4-5 years ago, so again I don’t remember the details, but I’m certain I would’ve known to try sudo, but that didn’t work for whatever reason. I remember trying really hard to get this command to work, but it wouldn’t, so I got so frustrated that I just went to /usr and ran chmod -R 777 ./. I honestly didn’t think this would break anything. Why would it? Surely relaxing the permissions on some files won’t break anything? I mean, the only time an error could occur is if I restricted the permissions, so relaxing them shouldn’t do anything.

At the time, I didn’t know about setuid, which is a permission flag that is important for allowing one user to run a command as a privileged user (like root, for example). So, what probably happened was I removed the setuid on /usr/bin/sudo, effectively breaking sudo. At the time I didn’t know what I had done, though, so hence I didn’t know how to fix it, so I just reinstalled Ubuntu.