root@server:~# while read -r name mergedir _; do size="$([ -d "${mergedir}" ] && du -s "${mergedir}" | cut -f 1)"; size_hr="$(awk -v s="${size:=0}" 'BEGIN { printf "%.2f\n", s/1024 }')"; echo "${name} ${mergedir} ${size:=0} ${size_hr}"; done <<< "$(docker inspect $(docker ps -qa) |  jq -r 'map([.Name, .GraphDriver.Data.MergedDir]) | .[] | "\(.[0])\t\(.[1])"')" | sort -nk3 | awk 'BEGIN{ print "NAME","MERGE_DIR","SIZE_B","SIZE_MB" } { print $0 }' | column -t
NAME                              MERGE_DIR                                                                                         SIZE_B  SIZE_MB
/zabbix-db_data_pgsql-1           /var/lib/docker/overlay2/93e67764c8b6f74e5686a5421c2aa3e79e8a11e81eb5869fbb13ad13ccb46130/merged  0       0.00
/zabbix-zabbix-server-1           /var/lib/docker/overlay2/9e1ecf3b598501ff76c28264c73cd34bf9697fdf7605ad467f8b39a7f8f36fca/merged  63604   62.11
/zabbix-zabbix-web-nginx-pgsql-1  /var/lib/docker/overlay2/4942fc913e4546c7090fba3614c9718607f7b0274abbc50ea6feed252efed58a/merged  179516  175.31
/zabbix-postgres-server-1         /var/lib/docker/overlay2/d7918d5dea06a3df43c847c91368341e56bda720a68cd6a7be6296dcb9a97f27/merged  272720  266.33
/zabbix-zabbix-web-service-1      /var/lib/docker/overlay2/eebdcc8ee3b0b2fc871db6c32a8988a52b4b200996ff28aa015e2bec8f039eb0/merged  754740  737.05