What is the process for running a 'docker exec' command within a Docker container?

Any command can be run in a container that is currently running by knowing its ID (or name).

docker exec -it <container_id_or_name> echo "I'm inside the container!"

Note:The container needs to be running.

Join iCert Global DevOps Training program now and take your career to the next level!

If the containers are operating on the same host, it is possible to run Docker commands from within the container. This can be achieved by specifying the Docker socket inside the container.

To do this, run the container and mount the 'docker.sock' in the following manner:

docker run -v /var/run/docker.sock:/var/run/docker.sock ...  

You can finally execute docker commands from inside the container.

Ready to level up your Docker skills? Enroll now in our comprehensive Docker Course!

• Use docker ps to get the name of the existing container
• Use the command docker exec -it <container name> /bin/bash to get a bash shell in the container
• Or directly use docker exec -it <container name> <command> to execute whatever command you specify in the container.

Run the container in the following manner:

docker run -it -d ashok/pyashokproj bin/bash  

If you would like to attach to an already running container:

docker exec -it CONTAINER_ID /bin/bash

This seemed pretty simple and helped me.

• To start an existing container which is stopped

docker start <container-name/ID>  

• To stop a running container

docker stop <container-name/ID>  

• Then to login to the interactive shell of a container

docker exec -it <container-name/ID> bash

This shouldhelp

docker create --name=new_container -it ubuntu  docker start new_container  // ps -a says 'Up X seconds'  docker exec new_container /path/to/my/command  // ps -a still says 'Up X+Y seconds'  docker exec new_container /path/to/another/command

$ docker exec -it ubuntu_bash bash

will create a new Bash session inside the container ubuntu_bash.

You can run a command in a container:

 docker-compose run <container name> <command>

 For example, to get a shell into your web container you might run 

docker-compose run web /bin/bash

To run a series of commands, you must wrap them in a single command using a shell. For example:

docker-compose run <name in yml> sh -c '<command 1> && <command 2> && <command 3>

This command to execute something in which a container is - 

docker exec <container_id/container_name> <instruction/cmd to be executed>

In your case, you are trying to send a mail I believe, so:

docker exec -d <container_name> sendmail -f [email protected]

This should run the command in a detached state run the process in the background.

In case you want your stdin to be open, replace -d with -i.

sendmail is an utility I believe, incase it is not running, run the command from inside the container and if needed install the sendmail util:

docker exec -i -t <container_name> /bin/bash (or /bin/sh)

To facilitate the debugging process, we are implementing the docker exec command, enabling users to initiate a process within their Docker container through the Docker API and command-line interface (CLI).

Run the cmd from the terminal and check :)

Also check the root process inside the container : PID 1
It appears that your container does not have a Docker runtime installed. I am uncertain whether this approach will be effective. Please run the container interactively and proceed to install Docker within it. Docker is designed to operate on a host or virtual machine, and it is unlikely to function within a container.

You can execute a command on the container using the docker exec command.

$ docker exec -d ubuntu_bash touch /tmp/execWorks  

Initially, you must access your host operating system and modify the docker.service file to permit TCP requests for Docker. This configuration allows any operating system within your network, including other containers linked to the host, to execute Docker commands.

$ docker exec -it ubuntu_bash bash