Executing commands with docker exec - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the docker exec command do?

It runs a new command inside a running Docker container without starting a new container.

beginner

How do you run an interactive shell inside a running container named webapp?

Use docker exec -it webapp /bin/bash to open an interactive bash shell inside the container.

intermediate

What does the -it option mean in docker exec?

-i keeps STDIN open, and -t allocates a pseudo-TTY, allowing interactive commands.

beginner

Can you use docker exec to run commands in a stopped container?

No, the container must be running to use docker exec.

beginner

How do you run a one-time command like ls /app inside a container named backend?

Run docker exec backend ls /app to list the contents of the /app directory inside the container.

What is required before you can use docker exec to run a command inside a container?

A The container must be running

B The container must be stopped

C Docker daemon must be stopped

D The container must be paused

You can only run commands inside containers that are currently running.

Which option allows you to run an interactive shell inside a container?

A -it

B -d

C -rm

D -p

The -it option keeps input open and allocates a terminal for interaction.

What happens if you run docker exec without specifying a command?

A It starts a new container

B It lists running containers

C It stops the container

D It returns an error

You must specify a command to run inside the container with docker exec.

How do you run a command inside a container named db to check the current directory?

A docker start db pwd

B docker run db pwd

C docker exec db pwd

D docker stop db pwd

docker exec db pwd runs the pwd command inside the running container named db.

Which of these commands opens an interactive shell inside a container named app?

A docker run -it app /bin/sh

B docker exec -it app /bin/sh

C docker exec app ls

D docker start -it app

Using docker exec -it app /bin/sh opens an interactive shell inside the running container.

Explain how to use docker exec to run an interactive shell inside a running container.

Think about how to keep input open and allocate a terminal.

Describe the limitations of docker exec regarding container state and command execution.

Consider when and how <code>docker exec</code> works.