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+# `gcrane`
+
+<img src="../../images/gcrane.png" width="40%">
+
+This tool implements a superset of the [`crane`](../crane/README.md) commands, with
+additional commands that are specific to [gcr.io](https://gcr.io).
+
+Note that this relies on some implementation details of GCR that are not
+consistent with the [registry spec](https://docs.docker.com/registry/spec/api/),
+so this may break in the future.
+
+## Installation
+
+Download [latest release](https://github.com/google/go-containerregistry/releases/latest).
+
+Install manually:
+
+```
+go install github.com/google/go-containerregistry/cmd/gcrane@latest
+```
+
+## Commands
+
+### ls
+
+`gcrane ls` exposes a more complex form of `ls` than `crane`, which allows for
+listing tags, manifests, and sub-repositories.
+
+### cp
+
+`gcrane cp` supports a `-r` flag that copies images recursively, which is useful
+for backing up images, georeplicating images, or renaming images en masse.
+
+### gc
+
+`gcrane gc` will calculate images that can be garbage-collected.
+By default, it will print any images that do not have tags pointing to them.
+
+This can be composed with `gcrane delete` to actually garbage collect them:
+```shell
+gcrane gc gcr.io/${PROJECT_ID}/repo | xargs -n1 gcrane delete
+```
+
+## Images
+
+You can also use gcrane as docker image
+
+```sh
+$ docker run --rm gcr.io/go-containerregistry/gcrane ls gcr.io/google-containers/busybox
+gcr.io/google-containers/busybox@sha256:4bdd623e848417d96127e16037743f0cd8b528c026e9175e22a84f639eca58ff
+gcr.io/google-containers/busybox:1.24
+gcr.io/google-containers/busybox@sha256:545e6a6310a27636260920bc07b994a299b6708a1b26910cfefd335fdfb60d2b
+gcr.io/google-containers/busybox:1.27
+gcr.io/google-containers/busybox:1.27.2
+gcr.io/google-containers/busybox@sha256:d8d3bc2c183ed2f9f10e7258f84971202325ee6011ba137112e01e30f206de67
+gcr.io/google-containers/busybox:latest
+```
+
+And it's also available with a shell, at the `:debug` tag:
+
+```sh
+docker run --rm -it --entrypoint "/busybox/sh" gcr.io/go-containerregistry/gcrane:debug
+```
+
+Tagged debug images are available at `gcr.io/go-containerregistry/gcrane/debug:[tag]`.