auto install latest docker by online/offline (binaries install)
source <(curl -sL https://docker-install.netlify.app/install.sh)
source <(curl -sL https://docker-install.netlify.app/install.sh) -s
./install.sh -f /root/docker-18.09.6.tgz
bash-completion file docker.bash should put same directory with install.sh
offline file: https://download.docker.com/linux/static/stable/