+ docker pull alpine:3.9 3.9: Pulling from library/alpine e7c96db7181b: Pulling fs layer e7c96db7181b: Verifying Checksum e7c96db7181b: Download complete e7c96db7181b: Pull complete Digest: sha256:7746df395af22f04212cd25a92c1d6dbc5a06a0ca9579a229ef43008d4d1302a Status: Downloaded newer image for alpine:3.9 docker.io/library/alpine:3.9