A few days back, I had a strange issue, well, more of a weird server setup. I was working on a new client's server, and they had this wired setup with half of the code running root and half as a different user; all permissions were f!!cked up, and the client didn't want me to change anything because the setup was ancient, and any changes could break the system.
In all that mess, I had to make some test changes right on the server, but when I tried to reset them, they were not budging; no matter what way I tried, nothing seemed to work. I spent about 2 hours getting rid of everything I did to get the previous code back, but nothing was going my way, and after much research, I found something that worked like a charm:
git checkout HEAD .
It checks out the most recent commit and reverts everything to it. There are several ways of doing this same thing, and I tried several of them, but this was the one that worked. So for me, this is what I will use to discard the changes when discarding is not working.
PS: I had to run it with sudo to make it work...