how to get number of replicas from deployment yaml using kubectl code example

Example 1: deployment example

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80

Example 2: scale deployment

# scale deployment in the default namespace, named myDeploymentName to have 3 pods
kubectl scale deployment/myDeploymentName --replicas=3

# scale deployment in the myNamespace namespace, named myDeploymentName to have 3 pods
kubectl scale deployment/myDeploymentName --replicas=3 -n myNamespace