Docker Get In Container - CSS

Introduction

Docker is a popular containerization platform used by developers to create, deploy and run applications. In order to manage and operate Docker containers, programmers need to understand the basic command-line interface (CLI) tools provided by Docker. One such tool is docker exec which is used to run a command inside a running Docker container. In this tutorial, we'll explore how to use docker exec to run a CSS (Cascading Style Sheets) file inside a Docker container.

Prerequisites

To follow this tutorial, you'll need:

• Docker installed and running on your computer
• A Docker image with a running container

If you need help with installing Docker, you can refer to the official Docker installation guide.

Steps

Step 1 - Start Container

First, we need to start a Docker container. You can either create a new container or use an existing one. For this tutorial, we'll use an existing nginx container. You can start the container by running the following command:

docker run -d --name my-nginx nginx

This command will start the nginx container in detached mode and name it my-nginx.

Step 2 - Get In Container

Now, we need to get into the my-nginx container. We can do this by running the following command:

docker exec -it my-nginx bash

This command will open up a new shell session inside the container. The -it option stands for "interactive terminal" which allows us to interact with the container's shell.

Step 3 - Create CSS File

Next, we'll create a new CSS file inside the container. In this example, we'll create a file named style.css. Run the following command inside the container:

touch style.css

This command will create an empty CSS file in the current directory.

Step 4 - Add CSS Code

Now, let's add some CSS code to our style.css file. You can use any text editor to edit the file. In this example, we'll use the echo command to add some CSS code to the file. Run the following command:

echo "body { background-color: #f3f3f3; }" > style.css

This command will add the CSS code body { background-color: #f3f3f3; } to our style.css file.

Step 5 - Verify CSS File

We've now created a CSS file inside our container. Let's verify that the file exists and the CSS code has been added to it. Run the following command inside the container:

cat style.css

This command will display the contents of the style.css file on the terminal.

Step 6 - Exit Container

Now that we've verified that our CSS file is working correctly, we can exit the container. Run the following command:

exit

This command will exit the shell session inside the container and return us to the host machine.

Step 7 - Copy CSS File

We've now created a CSS file inside our container. Let's copy it from the container to our host machine. Run the following command:

docker cp my-nginx:/style.css .

This command will copy the style.css file from the my-nginx container to the current directory on our host machine.

Step 8 - Verify CSS File

Our style.css file is now on our host machine. Let's verify that the CSS code we added in the container is still present. Open the style.css file in your favorite text editor and verify that the CSS code body { background-color: #f3f3f3; } is present.

Conclusion

In this tutorial, we explored how to use docker exec to run a CSS file inside a Docker container. We started by starting a container, getting into the container, creating a CSS file, adding CSS code to the file, verifying the CSS file, exiting the container, copying the CSS file from the container, and verifying the copied CSS file on the host machine. We hope this tutorial was helpful in your Docker containerization journey.