How to remove old and unused Docker images

Question

When running Docker for a long time, there are a lot of images in system. How can I remove all unused Docker images at once safety to free up the storage?

In additio

Answer 1

If you want to remove images pulled X months ago, you can try the below example which remove images created three months ago:

three_months_old_images=`docker images | grep -vi "" | tr -s ' ' | cut -d" " -f3,4,5,6 | grep "3 months ago" | cut -d" " -f1`
docker rmi $three_months_old_images