I know kubectl is not docker. I don't care. :-)
Official cheat sheet: https://kubernetes.io/docs/reference/kubectl/cheatsheet/
kubectl version -o json lists the version of kubectl you have installed and the version of the kubernetes cluster if you're connected.
kubectl get pods lists all pods in default namespace.
kubectl get pods --namespace foo lists all pods in namespace foo.
kubectl get deployment lists all deployments in default namespace
kubectl describe deployment bar describes deployment bar in the default namespace (stuff typically in the deployment.yml such as labels, annotations, images, resource request/limits, etc.)
kubectl scale deployments/myservice --replicas 3 scales the myservice deployment to 3 replicas (this could be up or down)
kubectl rollout restart deployment/myservice deletes and restarts all pods in the existing deployment for myservice
kubectl rollout status deployment/myservice checks the current status of the rollout for myservice
kubectl rollout history deployment/myservice lists known revisions of the deployment of myservice
kubectl get secret lists all secrets in default namespace (the number in the third column is the count of secret key value pairs in the file)
kubectl edit secret foo edits the secret named foo in the default namespace using the default text editor.
kubectl get configmap lists all configmaps in the default namespace
kubectl edit configmap foo edits the foo configmap in the default namespace using the default text editor.
kubectl apply -f mymanifest.yml applies the manifest in the specified yaml file, such as a secret, configmap, etc.
kubectl describe PodMetrics <pod_partial_name_starts_with> --namespace foo gives CPU and memory usage plus a bunch of other data such as labels and annotations. Nice because it will do search based on the pod partial name starting with what you specifiy - you don't have to give a specific exact pod name. Gives current CPU utilization in the ridiculous "nanoCPU" unit.
kubectl top pod <pod_name> --namespace foo --containers gives CPU and memory usage for the exact pod name you provide, broken out into which container. If you don't specify a pod name, it will return all the pods so you can grep for the pattern you want, or use -l labelname=labelvalue to filter by label.
Kubectl supports forwarding a local port to an active pod. If you want to forward traffic sent to port 3000 locally to port 4000 on a pod called my-pod-aaaaaaaaa-bbbbb in namespace foo, you can run this command:
kubectl port-forward --namespace foo my-pod-aaaaaaaaa-bbbbb 3000:4000
The instance of kubectl will forward that port on both IP v4 and IP v6 and run until cancelled.