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

Post a Comment

Popular posts from this blog

How to extract signing certificates from macOS binary files

Code signing is a macOS security technology that you use to certify that an app was created by you. Once an app is signed, the system can detect any change to the app—whether the change is introduced accidentally or by malicious code. As Apple Developer site says ( click here for more details  on code signing) : code signing allows the operating system to: Ensure that a piece of code has not been altered since it was signed.  The system can detect even the smallest change, whether it was intentional (by a malicious attacker, for example) or accidental (as when a file gets corrupted). When a code signature is intact, the system can be sure the code is as the signer intended. Identify code as coming from a specific source (a developer or signer).  The code signature includes cryptographic information that unambiguously points to a particular author. Determine whether code is trustworthy for a specific purpose.  Among other things, a developer can use a ...
Post a Comment
Read more

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}'
6 comments
Read more

How to get a certificate fingerprint as SHA-256, SHA-1 or MD5 using OpenSSL on mac

As per my old post ( http://anandmpandit.blogspot.in/2016/11/how-to-extract-signing-certificates.html ) , we can extract the binary signing certificates on mac using codesign tool. If you needed to get fingerprint details of the certificate in MD5, SHA1 or SHA256 format then you have run below steps on the extracted certificate file on macOS. SHA256: SHA256 Fingerprint=D3:0A:32:6C:77:77:93:B5:45:20:AC:C0:D4:7E:3A:84:34:50:96:54:08:7F:7D:63:4C:3E:06:3B:E8:1F:C1:90 SHA1: SHA1 Fingerprint=BF:2C:93:1F:BD:88:E5:4C:96:D8:86:D5:F1:E6:9B:B7:DE:76:51:62 MD5: MD5 Fingerprint=3C:A3:3B:76:6D:AE:3F:4B:4E:B2:AA:66:97:55:B8:76
Post a Comment
Read more