how to execute dockerfile code example

Example 1: docker expose port

docker run -p [external]:[Internal]

#example (will open in localhost:8080 to container port 80)
docker run -p 8080:80

Example 2: how run dockerfile

# Use the official image as a parent image.
FROM node:current-slim

# Set the working directory.
WORKDIR /usr/src/app

# Copy the file from your host to your current location.
COPY package.json .

# Run the command inside your image filesystem.
RUN npm install

# Inform Docker that the container is listening on the specified port at runtime.
EXPOSE 8080

# Run the specified command within the container.
CMD [ "npm", "start" ]

# Copy the rest of your app's source code from your host to your image filesystem.
COPY . .