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

How to remove a tagged image

1. docker rmi the tag first

2. docker rmi the image.

   # that can be done in one docker rmi call e.g.: # docker rmi

(this works Nov 2016, Docker version 1.12.2)

e.g.

$ docker images 
REPOSITORY              TAG                 IMAGE ID            CREATED             SIZE
usrxx/the-application   16112805            011fd5bf45a2        12 hours ago        5.753 GB
usryy/the-application   vx.xx.xx            5af809583b9c        3 days ago          5.743 GB
usrzz/the-application   vx.xx.xx            eef00ce9b81f        10 days ago         5.747 GB
usrAA/the-application   vx.xx.xx            422ba91c71bb        3 weeks ago         5.722 GB
usrBB/the-application   v1.00.18            a877aec95006        3 months ago        5.589 GB

$ docker rmi usrxx/the-application:16112805 && docker rmi 011fd5bf45a2
$ docker rmi usryy/the-application:vx.xx.xx && docker rmi 5af809583b9c
$ docker rmi usrzz/the-application:vx.xx.xx eef00ce9b81f
$ docker rmi usrAA/the-application:vx.xx.xx 422ba91c71bb
$ docker rmi usrBB/the-application:v1.00.18 a877aec95006

e.g. Scripted remove anything older than 2 weeks.

IMAGESINFO=$(docker images --no-trunc --format '{{.ID}} {{.Repository}} {{.Tag}} {{.CreatedSince}}' |grep -E " (weeks|months|years)")
TAGS=$(echo "$IMAGESINFO" | awk '{ print $2 ":" $3 }' )
IDS=$(echo "$IMAGESINFO" | awk '{ print $1 }' )
echo remove old images TAGS=$TAGS IDS=$IDS
for t in $TAGS; do docker rmi $t; done
for i in $IDS; do docker rmi $i; done