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If we use a Dockerfile to automatically create containers, we usually use the docker buildand runcommands. However, we usually combine most of the commands in a single run to tidy up a local image repository.

This article discusses combining commands such as docker buildand runinto one line.

Purpose of docker build and docker run commands

Using the docker buildand docker runcommands together can be helpful in a variety of situations. For example, if we are developing a new application and want to test it quickly, we can use these commands to build and run it in a container.

This saves you time and makes it easier for you to test your application.

docker buildThe command reads the instructions in the Dockerfile and uses them to create a Docker image. If we have already built a Dockerfile, we can use docker run -itthe command to run the image.

This command creates a new container from the image and runs it in interactive mode.

This mode means that we can interact with the container and run commands in it. Although we can run them individually, there are several ways to run them in one line.

Combine Docker commands using the double ampersand operator (&&)

One way to combine the docker buildand commands is to use the --rm flag with the command. This flag instructs Docker to remove the container when it exits automatically.docker run -itdocker run

docker buildThis flag means that we can run the and commands on a single line like this docker run:

$ docker run --rm -it $(docker build -t my-image)

In this example, my-image is the name of the Docker image that will be built and run. docker buildThe period at the end of the command .indicates that the Dockerfile is in the current directory.

Once we run this command, Docker will build the image using the instructions in the Dockerfile and then run that image in a new container. The --rm flag ensures that we automatically remove the container when it exits.

Combining Docker commands using command substitution

Another example of combining these two commands is to nest them together with the dollar sign ($) operator. The command would look like this:

docker run --rm -it $(docker build -t my-image)

$(...)The syntax is called command substitution. We use command substitution because Docker uses the output of one command as the argument of another command.

In the example above, Docker first executes docker build -t my-imagethe command and uses the output (the ID of the newly built Docker image) as an argument to the docker run command. By using substitution, Docker causes docker runthe command to run the Docker image using docker buildthe ID returned by the command.

Additionally, if we want to deploy our application to a production environment, we can use this method to build a Docker image and run it on a production server. This helps ensure that your application runs in a consistent environment and makes it easier to manage and maintain.

Summarize

In general, the docker buildand docker runcommands are powerful tools for building and running Docker images. Combined with these commands, we can build and run Docker images with just one line of code, making it easier and faster to develop, test, and deploy your applications.