<p>I am assuming you can still work with the failing hard drive.</p>
<p>Connect the "copy to" drive to the computer.</p>
<p>To use the "dd" command to make a byte-for-byte copy of the failing hard drive, we need to identify which is the "copy from" and "copy to" drives.</p>
<p>GParted or the "df -H" command can help.</p>
<p>Read through some documentation on "dd" to make sure you understand it. Because if you mix something up, you could end up with a blank hard drive.</p>
<p><a href="http://wiki.linuxquestions.org/wiki/Dd" rel="nofollow">http://wiki.linuxquestions.org/wiki/Dd</a></p>
<p><a href="http://www.debianhelp.co.uk/ddcommand.htm" rel="nofollow">http://www.debianhelp.co.uk/ddcommand.htm</a></p>
<p>Example: </p>
<pre><code>:~$ df -H
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 628G 288G 308G 49% /
udev 3.2G 312k 3.2G 1% /dev
none 3.2G 660k 3.2G 1% /dev/shm
none 3.2G 213k 3.2G 1% /var/run
none 3.2G 0 3.2G 0% /var/lock
none 3.2G 0 3.2G 0% /lib/init/rw
/dev/sdf1 500G 183M 500G 1% /media/External
</code></pre>
<p>I see that my "copy to" drive is "sdf" and my "copy from" drive is "sda".</p>
<p>I use the command:</p>
<p>dd if=/dev/sda of=/media/External/backup.img</p>
<p>to raw copy the entire "sda" hard drive to an image on a partition on the "sdf" drive. We can reach this partition, because it is mounted under "/media/External".</p>
