Execute bash shell from a running docker container

gistfile1.txt

$docker container ls
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
7fe71e1c7bdd        redis               "docker-entrypoint.s…"   9 seconds ago       Up 21 seconds       6379/tcp            unruffled_khorana
ad8a33ce3b2b        nginx               "nginx -g 'daemon of…"   14 minutes ago      Up 14 minutes       80/tcp              vigorous_meninsky

$docker exec -it 7fe /bin/bash

or

$docker exec -it $(docker ps | awk 'FNR == 2 { print $1; }') /bin/bash