How To Run A Command In Ubuntu?

What happens after you run the shred command?

• I'm selling a hard drive from a laptop on eBay. To wipe the data, I am running the shred command. This hard drive was using Ubuntu. What exactly happens after you run the shred command? Is it ready to have a new OS put on it, or is Ubuntu still on it but without any other data? After I run the shred command, what else do I need to do before I sell the hard drive?

• Answer:

  Shred stores patterns of ones and zero in all the bytes, over and over. It uses a sequence of different patterns to scramble the magnetic bits thoroughly. But be careful, if you apply shred to a filesystem, instead of the disc device, the ext3-4 filesystem can obviate the shredding because of the way it handles rewrites and cached writes. Which leaves you with basically no shredding at all. Once shredded, there is no OS. No data. No meaningful bit patterns. Just random bits. You are safe. Be sure to do more shred research first.