Skip to main content

How to erase the harddisk completly using linux ?

Erasing the entire hard disk using Linux:

Run the following command to fill your entire hard disk with zeros
$ dd  if=/dev/zero of=/dev/sda  bs=1M

The above command will whole hard disk with zeros. Note: this will take long time to complete.

Erasing/filling the hard Disk with random data:

We can fill the hard disk with random data in case of any security requirement  to prevent data loss. Run the below
$ dd  if=/dev/random of=/dev/sda  bs=1M


Erasing the MBR(Master Boot Record) of the Hard Disk.

To Erase only code area in your MBR:
  Run 
   
  $ dd  if=/dev/zero of=/dev/sda  bs=446 count=1

To Erase entire MBR :

  Run 

 $ dd if=/dev/zero of=/dev/sda  bs=512 count=1




Note : If linux is not installed, Boot into Linux image from Live CD to perform above operations  on the hard disk.


 

Comments

Popular posts from this blog

How to find firmware or boot ROM version in Mac OS X

Firmware and boot ROM version of your mac can be found in two ways.
Way 1 :
1. From "Apple" menu , choose "About This Mac" menu item. 2. Click " More Info " to open "System Profiler" application. 3. Under Contents -> Select Hardware Tree item.
On the right side panel Under hardware overview section, we can see Boot ROM Version and SMC (Firmware) Version.








Way 2 :
Run the below command in terminal to get boot ROM version and SMC(firmware) version :
$ system_profiler SPHardwareDataType | grep -i "Version" | awk -F ':' '{print $1 $2}'

How to decrypt the Filevault encrypted volume using Recovery HD ?

There might be a time where you want decrypt the FileVault encrypted mac, but you are facing issues in logging into Mac to perform decryption using system preferences. In such cases the following steps will help you in decrypting the disk using Recovery HD. Reboot the Mac, Go to recovery HD partition of the system. (To start your computer from Recovery, restart your Mac and hold down the Command and R keys at startup.)Open Terminal application from Utilities -> Application. First will need to identify the Logical Volume UUID of the encrypted drive using the diskutil corestorage list command: diskutil corestorage list

      4.  Once you have the UUID of the logical volume as shown in above picture, you can then either             unlock or decrypt the encrypted volume using the following commands.
      a) Using the password of an authorised account or the recovery key ( Provided by the                                FileVault at the time of enabling it) on the command line            …