update README file

README.md

@@ -2,6 +2,74 @@
 
 This repo will contains binaries that built from libraries in cli-runtime.
 
+## commands
+This repo can build a binary `cli-utils` by
+```
+GO111MODULE=on go generate
+GO111MODULE=on go build 
+```
+Note that the binary name has not been finally decided yet and is subject to change. Currently there are following candidates:
+```
+k2
+kapply
+kctl
+kutils
+kcli
+kut
+(other better name)
+```
+
+It provides following builtin commands as well as [dynamic commands](docs/dy/sample/REAME.md).
+
+```
+Usage:
+  cli-utils [command]
+
+Available Commands:
+  apply       Apply resource configurations.
+  delete      Delete resources from a Kubernetes cluster.
+  help        Help about any command
+  prune       Prune obsolete resources.
+```
+
+`apply` has a `status` subcommand, which can display status for resources.
+
+All of those commands can be run on a kustomization directory or a directory with raw Kubernetes yaml file.
+
+```shell
+# apply a kustomization directory to cluster
+./cli-utils --kubeconfig ~/.kube/config apply cmd/test-manifests/hello
+
+# display the status
+./cli-utils --kubeconfig ~/.kube/config apply status cmd/test-manifests/hello --wait --every 2 --count 30
+
+# delete the applied resources
+./cli-utils --kubeconfig ~/.kube/config delete cmd/test-manifests/hello
+
+# apply with watching for status
+./cli-utils --kubeconfig ~/.kube/config apply status cmd/test-manifests/hello
+```
+
+## libraries
+You can also use cli-utils as a library. It provides a library to run `apply`,
+`status`, `prune` and `delete` on a list of Unstructured resources.
+
+ ```Go
+import (
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"sigs.k8s.io/cli-utils/pkg"
+	)
+  c := pkg.InitializeCmd(io.Stdout, nil)
+  var resources []unstructured.Unstructured
+  err := c.Apply(resources)
+  err = c.Status(resources)
+  err = c.Prune(resources)
+  err = c.Delete(resources)
+```
+
+ ## Examples
+TODO: add examples
+
 ## Community, discussion, contribution, and support
 
 Learn how to engage with the Kubernetes community on the [community page](http://kubernetes.io/community/).