linux mint IT admin tips info

Backing Up Working Picam Images Over the Net With dd and Netcat

I recently updated my Picams to the latest Raspbian firmware after a camera module change, using:

sudo rpi-update

Once updated and working, complete with changed passwords etc. it is inconvenient to bring these units down physically to take the card out - one is in the garage - to DD clone the micro SD card images locally, so send the image direct from the working camera instead using netcat.

Get the IP of the target server:

eth0 Link encap:Ethernet HWaddr 00:23:54:3a:eb:9a  inet addr:

Use netcat to send the images over your net by setting up a listening server FIRST - any port number you like - on the target where the image is to be saved e.g:

stevee@hppavmint ~ $ netcat -l -p 9000 | dd of=pi.image

Then ssh into the Pi and send the full bootable SD card image after you know the device id:

stevee@pirear ~ $ sudo fdisk -l
[sudo] password for stevee:

Disk /dev/mmcblk0: 7948 MB, 7948206080 bytes

stevee@pirear ~ $ sudo dd if=/dev/mmcblk0 | netcat 9000
[sudo] password for stevee:

Check on progress periodically in a third terminal to see the image grow:

stevee@hppavmint ~ $ ll pi.image
-rw-r--r-- 1 stevee stevee 6355204096 Feb 22 09:06 pi.image

When done, you see the summary on the Pi:

stevee@pirear ~ $ sudo dd if=/dev/mmcblk0 | netcat 9000
[sudo] password for stevee:
15523840+0 records in
15523840+0 records out
7948206080 bytes (7.9 GB) copied, 1009.06 s, 7.9 MB/s

It took 16 minutes.

As I named it without a "typical" extension - even though Linux doesn't need one - (duh!) I'll rename it to Pi.img so it is better recognised for future general *.img searches and in the GUI apps for creating new SD cards in future using USB Writer.

mv -v pi.image pi.img

You can check it mounts locally with Disk Image Mounter:


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