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 disable USB ports on Mac OS X Mavericks, Yosemite or El Capitan ?

We might wonder how to disable the USB ports on Mac to prevent data copy to external USB mass storage devices. The USB kext on os x is loaded at the time of start of the system, this can be loaded / unloaded using kextload or kextunload command. To disable USB port on Mac , follow below steps:
On Macs running Mountain Lion, Mavericks  and Yosemite:
Unmount any connected USB devices to the system by running below command                  $diskutil unmount /Volumes/USBDISK.Now unload the USB related kernel extensions in the following order using kextunload command.sudo kextunload -b com.apple.driver.AppleUSBCardReader
sudo kextunload -b com.apple.driver.AppleUSBODD
sudo kextunload -b com.apple.iokit.IOUSBMassStorageClass

       This will unload the USB kext and disable the USB ports for storage devices on Mountain Lion, Mavericks  and Yosemite.
On Mac running El Capitan:
Unmount any connected USB devices to the system by running below command                  $diskutil unmount /Volumes/USBDI…