On 05/05/17 17:33, Robert Moskowitz wrote:

I have worked out the dd command to copy my work in progress 4Gb image:

dd if=/dev/sdb of=cubietruck.img bs=512 count=6268927

and restore it with:

dd if=/home/rgm/arm/Centos/cubietruck.img of=/dev/sdb bs=4M; sync

But I would like to compress this, making a .xz file that is expanded with xzcat.

I have not figured this out, so am asking for a bit of help (I have had to increase the root partition so backing up is a larger file now).

thanks

well, "dd if=/dev/sdb| xz > file.xz " ?

I prefer using myself pxz for parallel compression. As the tool we use to create the images just output raw .img file, we compress those like this : for file in *.img ; do echo "==== Compressing ${file} ======" ; time pv ${file} |pxz -T 16 > ${file}.xz ; done

Apply some salt/pepper to your needs and enjoy :-)