The Docker commit commands allow you to build up your own custom images. You can run commands inside your container and then snapshot the changes into a new image.
To do this section it makes sense to have two terminal windows open, split into top and bottom
- On bottom terminal window
# Run a new container
docker run -it ubuntu:16.04- On top terminal window
# Show the running container
docker ps- On bottom terminal window
# Add a new file
echo "This is a new file" > ~/foo- On the top terminal window
# Get the container id
docker ps
# Let's see the diff (yes the diff) of our container
docker diff <container id>
# Commit the changed container to a new image (Note the returned image id - sha256 hash)
docker commit <container id>- On the bottom terminal window
# Exit the running container
exit
# Run a new container from the image
docker run -it <image id>
# Check that the file is there
cat ~/foo