Questions regarding wiping hardrive data and file systems

[MADDSNIPER]

I plan to reinstall Linux Mint using full drive encryption but before i do this i wanted to wipe all the data on the hardrive. From some duckduckgo searches it seems using the dd command or the shred command is the way to go.

eg: shred –vfz –n 10 /dev/hda

ive also seen /dev/hda1 mentioned, how can i tell what exactly i need to use, i thought using my file manager would be able to tell me ( Caja 1.4.0 ) and i was able to find a /dev folder but no such mention of hda or dha1 etc inside it.

also i read that shred wont work on some file systems such as ext3, how can i tell what file systems my install is using?

im using linux mint 14.1 Mate 64bit.

[cwsnyder]

You might want to look at http://dban.org/ for Darik's Boot And Nuke. This bootable, GNU licensed, program is available as a CD/DVD disk image which can be burned to a CD-R, then booted from your computer and guide you in erasing your hard drive. There is a video showing how to use the program at http://www.youtube.com/watch?v=K9jfLDrm2Q0

[MADDSNIPER]

yea i noticed that program and i gather it uses the same commands, i guess i just wanted to know how to do it manually to increase my knowledge.

[cwsnyder]

According to man shred, shred will repeatedly overwrite files, but only files which exist at the time shred is invoked. It is designed to securely erase data files, but might miss file fragments from file updates. dd will overwrite even your operating and file systems, after which it will crash.

If you are going to use dd to repeatedly overwrite your file system and data to make it totally unrecoverable, you are going to first, have to be entering your commands in a terminal from a Live install, second, have to make sure exactly where what you want to erase resides on the physical drive, and third, set the parameters of dd properly to erase the data successively. Remember that dd will even overwrite any partitioning as well. Your chances of rendering your hard drive completely unusable is possible.

[MADDSNIPER]

ok thanks alot, i think i will have a look at running dban from a live cd as the easiest approach.

[DrHu]

also i read that shred wont work on some file systems such as ext3, how can i tell what file systems my install is using?

Your standard, whichever file manager is being installed: eg Thunar or Nautilus can show the mounts (hard drive names
--or you can use the terminal

Code: Select all

fdisk -l
--a name, like dos style, /dev/hda1 or dev/sda1
blkid 
--gibed the device numbers ( a long serial number)

http://www.thegeekstuff.com/2010/09/linux-fdisk/
http://www.linuxhowtos.org/manpages/8/blkid.htm

Gparted (GUI partition editor/formatter) also shows the hard drives
http://www.dedoimedo.com/computers/gparted.html

And you can always, in a terminal use the mount command to find the mounted drives, including the one that started your system
--or you could check the grub boot menu when your system started, pause your screen and use e to edit the line that is starting your Mint version (the one you normally load) and see which hard drive is being managed by that line..

[MADDSNIPER]

Thanks DrHu