--- title: "exec" description: "The exec command description and usage" keywords: ["command, container, run, execute"] --- # exec ```markdown Usage: docker exec [OPTIONS] CONTAINER COMMAND [ARG...] Run a command in a running container Options: -d, --detach Detached mode: run command in the background --detach-keys Override the key sequence for detaching a container -e, --env=[] Set environment variables --help Print usage -i, --interactive Keep STDIN open even if not attached --privileged Give extended privileges to the command -t, --tty Allocate a pseudo-TTY -u, --user Username or UID (format: [:]) ``` The `docker exec` command runs a new command in a running container. The command started using `docker exec` only runs while the container's primary process (`PID 1`) is running, and it is not restarted if the container is restarted. If the container is paused, then the `docker exec` command will fail with an error: $ docker pause test test $ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 1ae3b36715d2 ubuntu:latest "bash" 17 seconds ago Up 16 seconds (Paused) test $ docker exec test ls FATA[0000] Error response from daemon: Container test is paused, unpause the container before exec $ echo $? 1 ## Examples $ docker run --name ubuntu_bash --rm -i -t ubuntu bash This will create a container named `ubuntu_bash` and start a Bash session. $ docker exec -d ubuntu_bash touch /tmp/execWorks This will create a new file `/tmp/execWorks` inside the running container `ubuntu_bash`, in the background. $ docker exec -it ubuntu_bash bash This will create a new Bash session in the container `ubuntu_bash`.