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Comment by StephenSmith | Hacker News Reader

Okay, so what's the best way to image an SD card then? I use the following on a 64gb SD card -- is there a better way?

    dd if=/dev/sda | gzip > img.gz
    dd if=img.gz  | gunzip | dd of=/dev/sda

Do these not work?:

    gzip < /dev/sda > img.gz
    gunzip < img.gz > /dev/sda

Those should give you better block sizes than default dd without bs=128k or whatever.

For your first command:

    gzip -c /dev/sda > img.gz

For your second command:

    gunzip -c img.gz > /dev/sda

are what I suspect the blog post would recommend.

I would install pv (optional) and do

cat /dev/mmcblk0 | pv -abtrN Processed | gzip > img.gz

cat img.gz | gunzip | pv -abtrN Processed > /dev/mmcblk0

this is not the point of the article, but you may want to specify blocksize in those commands? ymmv tho