Sum the number of cores of running VMs in GKE
gcil | grep standard | grep RUNNING | awk '{print $3}' | cut -d'-' -f3 | paste -s -d+ | bc
Add tags to all VMs of an instance Group
gcloud compute instance-groups list-instances <GKE INSTANCE GROUP NAME> --format=json | jq .[].instance | cut -c93- | tr -d "\"" | xargs -d " " gcloud compute instances add-tags --tags=$TAG