Say, we have a container running Redis.

docker run redis

To execute the Redis CLI and access the Redis server within the container, we can execute a command that relays our given command to the container.

docker exec -it container-id redis-cli

What is happening here?

1. exec is the command for running a command within a container.
2. We’re telling Docker to tell the container that we want to provide input to the container by passing the -it flag.
3. We’re telling Docker to tell the container that we want to execute redis-cli.