====== Clone HDD or flash disks ======

===== Whole disk =====
  dd if=/dev/sda of=hdd.img
  dd if=hdd.img of=/dev/sda
  
===== One partition =====
  dd if=/dev/sda1 of=hdd.img
  dd if=hdd.img of=/dev/sda1
  
===== One partition =====
  dd if=/dev/sda1 of=hdd.img
  dd if=hdd.img of=/dev/sda1
  
===== CD =====
  dd if=/dev/cdrom of=/mnt/cdbackup.iso
  dd if=/mnt/cdbackup.iso of=/dev/cdrom

===== Over network =====
Clone drives over a network:\\
  dd if=/dev/sda | ssh username@host "dd of=/dev/sda"

Dump an image over a network:\\
  dd if=/dev/sda | ssh username@host "dd of=/mnt/hdd.img"

Clone a networked drive onto yours:\\
  ssh username@host "dd if=/dev/sda" | dd of=/dev/sda

Clone a networked image onto yours:\\
  ssh username@host "dd if=/mnt/hdd.img" | dd of=/dev/sda
===== Copying MBR =====
[[http://www.cyberciti.biz/faq/howto-copy-mbr|src]]\\
MBR Total Size = 446 + 64 + 2 = 512
  * 446 bytes - Bootstrap.
  * 64 bytes - Partition table.
  * 2 bytes - Signature.

512 vs 446 Bytes:
  * Use 446 bytes to overwrite or restore your /dev/XYZ MBR boot code only with the contents of $mbr.backup.file.
  * Use 512 bytes to overwrite or restore your /dev/XYZ the full MBR (which contains both boot code and the drive's partition table) with the contents of $mbr.backup.file.


**dd command to copy MBR (identically sized partitions only)**

Type dd command as follows:\\
  dd if=/dev/sda of=/dev/sdb bs=512 count=1

Above command will copy 512 bytes (MBR) from sda to sdb disk. This will only work if both discs have identically sized partitions.

**dd command for two discs with different size partitions**

  dd if=/dev/sda of=/tmp/mbrsda.bak bs=512 count=1

Now to restore the image to any sdb:\\
  dd if=/tmp/mbrsda.bak of=/dev/sdb bs=446 count=1
  
** example: 32Gb to 8Gb**\\
Given:
  * sdc: 32Gb with sdc1=4Gb, sdc2=4Gb, and 23Gb of free space.
  * sdd: 8Gb

Count number of blocks to copy:
  8015282176/512 = 15654848
  
Create image file:  
  sudo dd if=/dev/sdc of=jr1.img count=15654848
  
Write image file:
  sudo dd if=jr1.img of=/dev/sdd  
===== Watching Progress =====

First, find out the process id of the dd process by running the following in the new virtual terminal.
  $ pgrep -l '^dd$'
  8789 dd


To send the USR1 signal to the dd prcoess:
  $ kill -USR1  8789
  $


Note that as soon as the USR1 signal is detected, dd will print out the current statistics to its STDERR.
  $ dd if=/dev/random of=/dev/null bs=1K count=100
  0+14 records in
  0+14 records out
  204 bytes (204 B) copied, 24.92 seconds, 0.0 kB/s