Update readme

Author: polldo

README.md

@@ -38,6 +38,14 @@ Use this command to provision a device:
 
 `$ iot-cloud-cli device create --name <deviceName> --port <port> --fqbn <deviceFqbn>`
 
+## Device commands
+
+Once a device has been created thorugh the provisioning procedure, it can be deleted by using the following command:
+`$ iot-cloud-cli device delete --id <deviceID>`
+
+Devices currently present on Arduino IoT Cloud can be retrieved by using this command:
+`$ iot-cloud-cli device list`
+
 
 ## Use iot-cloud-cli as a virtual device