Which command is used to execute another process inside a running Docker container?

Which command is used to execute another process inside a running Docker container?

• A. docker exec
• B. docker run
• C. docker attach
• D. docker kill

Answer: (A)

To run another process inside a running container, you need a command that injects a new process into that container’s existing namespace and filesystem. docker exec does exactly that: it starts the specified command as a new process inside the running container, using the container’s environment. You can run interactively with -it, for example: docker exec -it my-container bash. This differs from starting a new container with docker run, which would create a separate container; it also differs from docker attach, which connects you to the container’s main process rather than starting a new one. That’s why docker exec is the right choice for executing an additional process inside a running container.

To run another process inside a running container, you need a command that injects a new process into that container’s existing namespace and filesystem. docker exec does exactly that: it starts the specified command as a new process inside the running container, using the container’s environment. You can run interactively with -it, for example: docker exec -it my-container bash. This differs from starting a new container with docker run, which would create a separate container; it also differs from docker attach, which connects you to the container’s main process rather than starting a new one. That’s why docker exec is the right choice for executing an additional process inside a running container.