docs: Update getting-started.adoc

Author: csautter

modules/ROOT/pages/getting-started.adoc

@@ -239,10 +239,7 @@ We can test ZooKeeper by running the ZooKeeper CLI shell. The easiest way to do
 
 [source,bash]
 ----
-kubectl exec -i -t simple-zk-server-primary-0 -- bin/zkCli.sh
-# optional, determine the port
-PORT=$(kubectl get pod simple-zk-server-primary-0 -o=jsonpath='{.spec.containers[0].ports[0].containerPort}')
-echo $PORT
+PORT="$(kubectl get pod simple-zk-server-primary-0 -o=json | jq '.spec.containers[].ports[] | select(.name == "zk") | .containerPort')"
 kubectl exec -i -t simple-zk-server-primary-0 -- bin/zkCli.sh -server "localhost:$PORT"
 ----