Wondering why you have a strange error such as ‘from …’ when running docker build. The reason is linked to an older version of docker installed.
You need to remove the current docker.io.
sudo apt-cache policy docker.io
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
sudo apt-get update
sudo apt-cache policy docker-ce
sudo apt-get remove docker docker-engine docker.io
sudo apt-get install docker-ce
Run the following command:
sudo usermod -a -G docker <yourusername>
If you still have issue running docker instead of sudo docker, try to reboot. Worked for me.