…because I’m an idiot. Fortunately it was a backup drive, and I believe the only thing on it was backups of backups fortunately.
I was setting up to installing Debian on another computer and ran:
sudo dd bs=4M if=debian-12.4.0-amd64-DVD-1.iso of=/dev/s?? status=progress oflag=sync
to flash it to a usb drive. I hadn’t realized the system had reassigned hard drive device ID from the previous day, and for about 3 seconds it executed before I terminated the process once I realized what I did.
I immediately created a disk image of the Data-Destroyed hard drive just in case I screwed something up in trying to recover it.
I ran testdisk, but I’m not really sure how to use it or how to try to recover the data. The drive mounts okay, and shows it has 19,336 items totalling 8.2 GB of the Debian system files.
Is this beyond repair?
The files that were overwritten in the first 3 seconds are gone. Though, It’s likely that most, if not all the data is okay. Hopefully its just the pointers to the files that was over written, meaning you’ll have to use some file recovery software on the disk/image to get it back. I don’t have any software suggestions to do that.