docker image prune

Description	Remove unused images
Usage	`docker image prune [OPTIONS]`

Description

Remove all dangling images. If -a is specified, also remove all images not referenced by any container.

Options

Option	Default	Description
`-a, --all`		Remove all unused images, not just dangling ones
`--filter`		Provide filter values (e.g. `until=<timestamp>`)
`-f, --force`		Do not prompt for confirmation

Examples

Example output:

$ docker image prune -a

WARNING! This will remove all images without at least one container associated to them.
Are you sure you want to continue? [y/N] y
Deleted Images:
untagged: alpine:latest
untagged: alpine@sha256:3dcdb92d7432d56604d4545cbd324b14e647b313626d99b889d0626de158f73a
deleted: sha256:4e38e38c8ce0b8d9041a9c4fefe786631d1416225e13b0bfe8cfa2321aec4bba
deleted: sha256:4fe15f8d0ae69e169824f25f1d4da3015a48feeeeebb265cd2e328e15c6a869f
untagged: alpine:3.3
untagged: alpine@sha256:4fa633f4feff6a8f02acfc7424efd5cb3e76686ed3218abf4ca0fa4a2a358423
untagged: my-jq:latest
deleted: sha256:ae67841be6d008a374eff7c2a974cde3934ffe9536a7dc7ce589585eddd83aff
deleted: sha256:34f6f1261650bc341eb122313372adc4512b4fceddc2a7ecbb84f0958ce5ad65
deleted: sha256:cf4194e8d8db1cb2d117df33f2c75c0369c3a26d96725efb978cc69e046b87e7
untagged: my-curl:latest
deleted: sha256:b2789dd875bf427de7f9f6ae001940073b3201409b14aba7e5db71f408b8569e
deleted: sha256:96daac0cb203226438989926fc34dd024f365a9a8616b93e168d303cfe4cb5e9
deleted: sha256:5cbd97a14241c9cd83250d6b6fc0649833c4a3e84099b968dd4ba403e609945e
deleted: sha256:a0971c4015c1e898c60bf95781c6730a05b5d8a2ae6827f53837e6c9d38efdec
deleted: sha256:d8359ca3b681cc5396a4e790088441673ed3ce90ebc04de388bfcd31a0716b06
deleted: sha256:83fc9ba8fb70e1da31dfcc3c88d093831dbd4be38b34af998df37e8ac538260c
deleted: sha256:ae7041a4cc625a9c8e6955452f7afe602b401f662671cea3613f08f3d9343b35
deleted: sha256:35e0f43a37755b832f0bbea91a2360b025ee351d7309dae0d9737bc96b6d0809
deleted: sha256:0af941dd29f00e4510195dd00b19671bc591e29d1495630e7e0f7c44c1e6a8c0
deleted: sha256:9fc896fc2013da84f84e45b3096053eb084417b42e6b35ea0cce5a3529705eac
deleted: sha256:47cf20d8c26c46fff71be614d9f54997edacfe8d46d51769706e5aba94b16f2b
deleted: sha256:2c675ee9ed53425e31a13e3390bf3f539bf8637000e4bcfbb85ee03ef4d910a1

Total reclaimed space: 16.43 MB

Filtering (--filter)

The filtering flag (--filter) format is of "key=value". If there is more than one filter, then pass multiple flags (e.g., --filter "foo=bar" --filter "bif=baz")

The currently supported filters are:

until (<timestamp>) - only remove images created before given timestamp
label (label=<key>, label=<key>=<value>, label!=<key>, or label!=<key>=<value>) - only remove images with (or without, in case label!=... is used) the specified labels.

The until filter can be Unix timestamps, date formatted timestamps, or Go duration strings supported by ParseDuration (e.g. 10m, 1h30m) computed relative to the daemon machine’s time. Supported formats for date formatted time stamps include RFC3339Nano, RFC3339, 2006-01-02T15:04:05, 2006-01-02T15:04:05.999999999, 2006-01-02T07:00, and 2006-01-02. The local timezone on the daemon will be used if you do not provide either a Z or a +-00:00 timezone offset at the end of the timestamp. When providing Unix timestamps enter seconds[.nanoseconds], where seconds is the number of seconds that have elapsed since January 1, 1970 (midnight UTC/GMT), not counting leap seconds (aka Unix epoch or Unix time), and the optional .nanoseconds field is a fraction of a second no more than nine digits long.

The label filter accepts two formats. One is the label=... (label=<key> or label=<key>=<value>), which removes images with the specified labels. The other format is the label!=... (label!=<key> or label!=<key>=<value>), which removes images without the specified labels.

Note
Predicting what will be removed
If you are using positive filtering (testing for the existence of a label or that a label has a specific value), you can use docker image ls with the same filtering syntax to see which images match your filter.
However, if you are using negative filtering (testing for the absence of a label or that a label doesn't have a specific value), this type of filter doesn't work with docker image ls so you cannot easily predict which images will be removed. In addition, the confirmation prompt for docker image prune always warns that all dangling images will be removed, even if you are using --filter.

The following removes images created before 2017-01-04T00:00:00:

$ docker images --format 'table {{.Repository}}\t{{.Tag}}\t{{.ID}}\t{{.CreatedAt}}\t{{.Size}}'
REPOSITORY          TAG                 IMAGE ID            CREATED AT                      SIZE
foo                 latest              2f287ac753da        2017-01-04 13:42:23 -0800 PST   3.98 MB
alpine              latest              88e169ea8f46        2016-12-27 10:17:25 -0800 PST   3.98 MB
busybox             latest              e02e811dd08f        2016-10-07 14:03:58 -0700 PDT   1.09 MB

$ docker image prune -a --force --filter "until=2017-01-04T00:00:00"

Deleted Images:
untagged: alpine:latest
untagged: alpine@sha256:dfbd4a3a8ebca874ebd2474f044a0b33600d4523d03b0df76e5c5986cb02d7e8
untagged: busybox:latest
untagged: busybox@sha256:29f5d56d12684887bdfa50dcd29fc31eea4aaf4ad3bec43daf19026a7ce69912
deleted: sha256:e02e811dd08fd49e7f6032625495118e63f597eb150403d02e3238af1df240ba
deleted: sha256:e88b3f82283bc59d5e0df427c824e9f95557e661fcb0ea15fb0fb6f97760f9d9

Total reclaimed space: 1.093 MB

$ docker images --format 'table {{.Repository}}\t{{.Tag}}\t{{.ID}}\t{{.CreatedAt}}\t{{.Size}}'

REPOSITORY          TAG                 IMAGE ID            CREATED AT                      SIZE
foo                 latest              2f287ac753da        2017-01-04 13:42:23 -0800 PST   3.98 MB

The following removes images created more than 10 days (240h) ago:

$ docker images

REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
foo                 latest              2f287ac753da        14 seconds ago      3.98 MB
alpine              latest              88e169ea8f46        8 days ago          3.98 MB
debian              jessie              7b0a06c805e8        2 months ago        123 MB
busybox             latest              e02e811dd08f        2 months ago        1.09 MB
golang              1.7.0               138c2e655421        4 months ago        670 MB

$ docker image prune -a --force --filter "until=240h"

Deleted Images:
untagged: golang:1.7.0
untagged: golang@sha256:6765038c2b8f407fd6e3ecea043b44580c229ccfa2a13f6d85866cf2b4a9628e
deleted: sha256:138c2e6554219de65614d88c15521bfb2da674cbb0bf840de161f89ff4264b96
deleted: sha256:ec353c2e1a673f456c4b78906d0d77f9d9456cfb5229b78c6a960bfb7496b76a
deleted: sha256:fe22765feaf3907526b4921c73ea6643ff9e334497c9b7e177972cf22f68ee93
deleted: sha256:ff845959c80148421a5c3ae11cc0e6c115f950c89bc949646be55ed18d6a2912
deleted: sha256:a4320831346648c03db64149eafc83092e2b34ab50ca6e8c13112388f25899a7
deleted: sha256:4c76020202ee1d9709e703b7c6de367b325139e74eebd6b55b30a63c196abaf3
deleted: sha256:d7afd92fb07236c8a2045715a86b7d5f0066cef025018cd3ca9a45498c51d1d6
deleted: sha256:9e63c5bce4585dd7038d830a1f1f4e44cb1a1515b00e620ac718e934b484c938
untagged: debian:jessie
untagged: debian@sha256:c1af755d300d0c65bb1194d24bce561d70c98a54fb5ce5b1693beb4f7988272f
deleted: sha256:7b0a06c805e8f23807fb8856621c60851727e85c7bcb751012c813f122734c8d
deleted: sha256:f96222d75c5563900bc4dd852179b720a0885de8f7a0619ba0ac76e92542bbc8

Total reclaimed space: 792.6 MB

$ docker images

REPOSITORY          TAG                 IMAGE ID            CREATED              SIZE
foo                 latest              2f287ac753da        About a minute ago   3.98 MB
alpine              latest              88e169ea8f46        8 days ago           3.98 MB
busybox             latest              e02e811dd08f        2 months ago         1.09 MB

The following example removes images with the label deprecated:

$ docker image prune --filter="label=deprecated"

The following example removes images with the label maintainer set to john:

$ docker image prune --filter="label=maintainer=john"

This example removes images which have no maintainer label:

$ docker image prune --filter="label!=maintainer"

This example removes images which have a maintainer label not set to john:

$ docker image prune --filter="label!=maintainer=john"

Note
You are prompted for confirmation before the prune removes anything, but you are not shown a list of what will potentially be removed. In addition, docker image ls doesn't support negative filtering, so it difficult to predict what images will actually be removed.