Docker Containers - The Commands

The summary of Docker container commands

• docker run is the command to start new containers. You give it the name of an image and it starts a container from it. This example starts an interactive container from the Ubuntu image and tells it to run the Bash shell: docker run -it ubuntu bash.

• Ctrl-PQ is how you detach from a container without killing the process you’re attached to. You’ll use it frequently to detach from running containers without killing them.

• docker ps lists all running containers, and you can add the -a flag to also see containers in the stopped (Exited) state.

• docker exec allows you to run commands inside containers. The following command will start a new Bash shell inside a running container and connect your terminal to it: docker exec -it <container-name> bash. For this to work, the container must include the Bash shell. This command runs a ps command inside a running container without opening an interactive shell session: docker exec <container-name> ps.

• docker stop stops a running container and puts it in the Exited (137) state. It issues a SIGTERM to the container’s PID 1 process and allows the container 10 seconds to gracefully quit. If the process hasn’t cleaned up and stopped within 10 seconds, it sends a SIGKILL to force the container to immediately terminate.

• docker restart restarts a stopped container.

• docker rm deletes a stopped container. You can add the -f flag to delete the container without having to stop it first.

• docker inspect shows you detailed configuration and run-time information about a container.

• docker debug attaches a debug shell to a container or image and lets you run commands that aren’t available inside the container or image. It requires a Pro, Team, or Business Docker subscription.