I accidentally used dd on my secondary hard drive while trying to write an install disk. The command was dd bs=4M if=foo.iso of=/dev/sdb
Fortunately, I umounted the flash drive and not the hard drive, so the drive was still mounted.
Following another forum post, I was able to pull
sdb1 was ext4, sdb2 was ntfs. I'm fairly sure it was gpt, but I don't know how to check.
That's as far as I got though. I'm a bit of a newbie, please give me step by step if possible.