The docker exec command runs a command in a running container.
$ docker exec [OPTIONS] CONTAINER COMMAND [ARG...]Here,
Options
-detach , -d → Detached mode: run command in the background--detach-keys → Override the key sequence for detaching a container--env , -e → Set environment variables--env-file → Read in a file of environment variables--interactive, -i → Keep STDIN open even if not attached--privileged → Give extended privileges to the command--tty , -t → Allocate a pseudo-TTY--user , -u → Username or UID (format: <name|uid>[:<group|gid>])--workdir , -w → Working directory inside the containerFirst, start the container if you haven’t already:
$ docker run --name cloudyfox_bash --rm -it cloudyfox /bin/bashThen, execute the container:
$ docker exec -d cloudyfox_bash touch /tmp/cloudyfoxFileHere, a new file /tmp/cloudyfoxFile will be created in the background.
Now, execute an interactive bash shell on the container:
$ docker exec -it cloudyfox_bash /bin/bashIt will create a new bash session in the container cloudyfox_bash.
Also, set an environment variable:
$ docker exec -it -e VAR=10 cloudyfox_bash /bin/bashNote: This $VAR will only be valid on the current bash session.