Hello @Aniket ,
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.
COMMAND will run in the default directory of the container. If the underlying image has a custom directory specified with the WORKDIR directive in its Dockerfile, this will be used instead.
COMMAND should be an executable, a chained or a quoted command will not work. Example: docker exec -ti my_container "echo a && echo b" will not work, but docker exec -ti my_container sh -c "echo a && echo b" will.
Run docker exec on a running container
First, start a container.
$ docker run --name ubuntu_bash --rm -i -t ubuntu bash
This will create a container named ubuntu_bash and start a Bash session.
Next, execute a command on the container.
$ 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.
Next, execute an interactive bash shell on the container.
$ docker exec -it ubuntu_bash bash
This will create a new Bash session in the container ubuntu_bash.
Next, set an environment variable in the current bash session.
$ docker exec -it -e VAR=1 ubuntu_bash bash
This will create a new Bash session in the container ubuntu_bash with environment variable $VAR set to “1”. Note that this environment variable will only be valid on the current Bash session.
By default docker exec command runs in the same working directory set when container was created.
$ docker exec -it ubuntu_bash pwd
You can select working directory for the command to execute into
$ docker exec -it -w /root ubuntu_bash pwd
Hope this is helpful!!