you can use this template to create deployment without bash cat <

---
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:1.7.9
        ports:
        - containerPort: 80
EOF

If I understand your question correctly, it sounds like you are trying to retrieve the current deployments as YAML so you can play around with them.

Here's the command I believe you need for this:

kubectl get  deployments -o yaml 

You can run kubectl create deployment my-deployment --image=my-image

Then if you want the manifest: kubectl get deployment my-deployment --output=yaml

I see two simple ways to do that:

1. Using echo. Example:

echo "
---
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:1.7.9
        ports:
        - containerPort: 80
" > deployment.yaml

2. Creating a resource using kubectl and then outputing it to yaml:

   kubectl create deployment nginx --image=nginx --replicas=1

   kubectl get deployment nginx --export=true -o yaml

All the answers so far advocate actually deploying to the cluster, then retrieving the running deployment.

Using the --dry-run you can get the YAML format of the object without actually deploying anything. For example:

kubectl create deployment nginx --image=nginx --dry-run -o yaml

Will output the deployment YAML to stdout:

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: nginx
  name: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx
        name: nginx
        resources: {}
status: {}

You can run following command to generate nginx deployment, even you dont have to create deployment for this.

kubectl create deployment mynginx --image=nginx -o yaml --dry-run > /tmp/mydeployment.yaml

cat /tmp/mydeployment.yaml

Now, you can edit this yaml file to add more details. But this gives you a basic structure to start with.

As stated in the error, it cannot find the location of your file

You should specify the path where your file is, if you run it through a script

If ran through command line only, the file specified is not in the directory you are executing the command

#!/bin/bash
DEPLOYMENT_LOCATION="~/deployments"
kubectl create -f "$DEPLOYMENT_LOCATION/deployment.yaml"

or if relative to your script

#!/bin/bash
SCRIPT_DIR="`dirname \"$0\"`"
kubectl create -f "$SCRIPT_DIR/deployments/deployment.yaml"