[SOLVED] How to compress the latest docker image?

Issue

I want to compress (and later send with rsync to other server) my last backup Docker images for automated. I try this:

sudo docker save -o dockdebian.tar.gz | sudo docker images | awk 'NR==2{ print $3 }'

Select the the first ID of the image list. But gave me this error:

"docker save" requires at least 1 argument.

See 'docker save --help'.

Usage: docker save [OPTIONS] IMAGE [IMAGE...]

Save one or more images to a tar archive (streamed to STDOUT by default)

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Solution

You have to use command substitution in shell. More info here: https://www.gnu.org/software/bash/manual/html_node/Command-Substitution.html

docker save -o dockdebian.tar $(sudo docker images | awk 'NR==2{ print $3 }')

or

docker save -o dockdebian.tar `sudo docker images | awk 'NR==2{ print $3 }'`

Answered By - rafal1337

Answer Checked By - Mildred Charles (WPSolving Admin)