$ kubectl get po
NAME          READY   STATUS      RESTARTS   AGE
pod-running   1/1     Running     0          10s
pod-pending   0/1     Pending     0          20s
pod-failed    0/1     Failed      0          30s
pod-unknown   0/1     Unknown     0          40s
job-kqpxc     0/1     Completed   0          50s

$ kubectl reap po
pod/pod-pending deleted
pod/pod-failed deleted
pod/pod-unknown deleted
pod/job-kqpxc deleted

$ kubectl get cm
NAME       DATA   AGE
config-1   1      0m15s
config-2   1      0m10s

$ cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx
    volumeMounts:
    - name: config-1-volume
      mountPath: /var/config
  volumes:
  - name: config-1-volume
    configMap:
      name: config-1
EOF

$ kubectl reap cm
configmap/config-2 deleted

$ kubectl reap cm --interactive # or '-i'
? Are you sure to delete configmap/config-1? Yes
configmap/config-1 deleted
? Are you sure to delete configmap/config-2? No
? Are you sure to delete configmap/config-3? Yes
configmap/config-3 deleted

$ kubectl reap --help

Delete unused resources. Supported resources:

- Pods (whose status is not Running)
- ConfigMaps (not used by any Pods)
- Secrets (not used by any Pods or ServiceAccounts)
- PersistentVolumes (not satisfying any PersistentVolumeClaims)
- PersistentVolumeClaims (not used by any Pods)
- Jobs (completed)
- PodDisruptionBudgets (not targeting any Pods)
- HorizontalPodAutoscalers (not targeting any resources)

Usage:
  kubectl reap RESOURCE_TYPE [flags]

Examples:

  # Delete ConfigMaps not mounted on any Pods and in the current namespace and context
  $ kubectl reap configmaps

  # Delete unused ConfigMaps and Secrets in the namespace/my-namespace and context/my-context
  $ kubectl reap cm,secret -n my-namespace --context my-context

  # Delete ConfigMaps not mounted on any Pods and across all namespace
  $ kubectl reap cm --all-namespaces

  # Delete Pods whose status is not Running as client-side dry-run
  $ kubectl reap po --dry-run=client

Flags:
  -A, --all-namespaces                 If true, delete the targeted resources across all namespace except kube-system
      --allow-missing-template-keys    If true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats. (default true)
      --as string                      Username to impersonate for the operation
      --as-group stringArray           Group to impersonate for the operation, this flag can be repeated to specify multiple groups.
      --cache-dir string               Default cache directory (default "/Users/micnncim/.kube/cache")
      --certificate-authority string   Path to a cert file for the certificate authority
      --client-certificate string      Path to a client certificate file for TLS
      --client-key string              Path to a client key file for TLS
      --cluster string                 The name of the kubeconfig cluster to use
      --context string                 The name of the kubeconfig context to use
      --dry-run string[="unchanged"]   Must be "none", "server", or "client". If client strategy, only print the object that would be sent, without sending it. If server strategy, submit server-side request without persisting the resource. (default "none")
      --field-selector string          Selector (field query) to filter on, supports '=', '==', and '!='.(e.g. --field-selector key1=value1,key2=value2). The server only supports a limited number of field queries per type.
      --force                          If true, immediately remove resources from API and bypass graceful deletion. Note that immediate deletion of some resources may result in inconsistency or data loss and requires confirmation.
      --grace-period int               Period of time in seconds given to the resource to terminate gracefully. Ignored if negative. Set to 1 for immediate shutdown. Can only be set to 0 when --force is true (force deletion). (default -1)
  -h, --help                           help for kubectl
      --insecure-skip-tls-verify       If true, the server's certificate will not be checked for validity. This will make your HTTPS connections insecure
  -i, --interactive                    If true, a prompt asks whether resources can be deleted
      --kubeconfig string              Path to the kubeconfig file to use for CLI requests.
  -n, --namespace string               If present, the namespace scope for this CLI request
  -o, --output string                  Output format. One of: json|yaml|name|go-template|go-template-file|template|templatefile|jsonpath|jsonpath-as-json|jsonpath-file.
  -q, --quiet                          If true, no output is produced
      --request-timeout string         The length of time to wait before giving up on a single server request. Non-zero values should contain a corresponding time unit (e.g. 1s, 2m, 3h). A value of zero means don't timeout requests. (default "0")
  -l, --selector string                Selector (label query) to filter on, supports '=', '==', and '!='.(e.g. -l key1=value1,key2=value2)
  -s, --server string                  The address and port of the Kubernetes API server
      --template string                Template string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview].
      --timeout duration               The length of time to wait before giving up on a delete, zero means determine a timeout from the size of the object
      --tls-server-name string         Server name to use for server certificate validation. If it is not provided, the hostname used to contact the server is used
      --token string                   Bearer token for authentication to the API server
      --user string                    The name of the kubeconfig user to use
  -v, --version                        If true, show the version of this plugin
      --wait                           If true, wait for resources to be gone before returning. This waits for finalizers.