How can you override the default command in a Docker container when running it?

How can you override the default command in a Docker container when running it?

• A. Add the command to the end of the docker run command
• B. Modify the image's entrypoint in the registry
• C. Use a different tag and re-pull
• D. Set an environment variable to override

Answer: (A)

In Docker, the image can define a default command (CMD) that runs when you start a container. Providing your own command at the end of the docker run line tells Docker to execute that new command instead of the image’s default. This is the most direct way to override what the container runs without rebuilding the image. If the image also specifies an entrypoint, the command you pass becomes arguments to that entrypoint, rather than replacing it; to replace the entrypoint itself you’d use --entrypoint. The other approaches don’t directly change the startup command in the same way.

In Docker, the image can define a default command (CMD) that runs when you start a container. Providing your own command at the end of the docker run line tells Docker to execute that new command instead of the image’s default. This is the most direct way to override what the container runs without rebuilding the image. If the image also specifies an entrypoint, the command you pass becomes arguments to that entrypoint, rather than replacing it; to replace the entrypoint itself you’d use --entrypoint. The other approaches don’t directly change the startup command in the same way.