Docker-ls contains two CLI tools: docker-ls and docker-rm . The following paragraphs give an overview over their usage; please consult the CLI help (option -h) for more details.

docker-ls

docker-ls is capable of browsing docker registries. Three subcommands are available

docker-ls repositories: Obtains a list of repositories on the server. This is not supported by the official docker hub.
docker-ls tags: Lists all tags in a a particular repository.
docker-ls tag: Inspect a particular tag. This command displays a condensed version of the corresponding manifest by default, but the --raw-manifest option can be used to dump the full manifest. The --parse-history option can be used to display the JSON-encoded history within the manifest.

Important command line flags

This list is not comprehensive; please consult the command line (-h) help for all options.

--registry <url> Connect to the registry at URL. The URL must include the protocol (http / https).
--user <user> Username for authentication.
--password <password> Password for authentication.
--level <depth> The repositories and tags subcommands support the level option for recursing into more details. Depth 0 (default) and 1 are supported. Please note the recursing means more requests and is slower.
--json Switch output format from YAML to JSON.
--basic-auth Use HTTP basic auth for authentication (instead of token authentication).
--allow-insecure Do not validate SSL certificates (useful for registries secured with a self-signed cert).

Examples

List all repositories in a custom registry:

docker-ls repositories --registry https://my.registry.org --user hanni --password hanni123

List all repositories in a custom registry, including their tags:

docker-ls repositories --registry https://my.registry.org --user hanni --password hanni123 --level 1

List all tags in stuff/busybox using HTTP basic auth

docker-ls tags --registry https://my.registry.org --user hanni --password hanni123 --basic-auth stuff/busybox

Inspect tag stuff/busybox:latest, no authentication, JSON outut.

docker-ls tag --registry https://my.registry.org --json stuff/busybox:latest

Inspect tag stuff/busybox:latest, no authentication, dump the raw manifest with parsed history as JSON.

docker-ls tag --registry https://my.registry.org --json --raw-manifest --parse-history stuff/busybox:latest

docker-rm

docker-rm can delete particular tags. Example:

docker-rm --registry https://foo.bar.org --user someuser --password somepass busybox/sha256:51fef[...]

(the sha256 has been truncated for brevity). Please consult the command line help for a full list of all arguments.

Some remarks:

The tag must be specified as a content sha256.
While tags can be deleted, the current registry implementation will (to the best of my knowledge) not free the space associated with any now-unused layers.
BE CAREFUL! The API does not implement undelete :)