How to Use Docker Compose Exec: Simple Guide

Use docker compose exec [service] [command] to run a command inside a running container of a service defined in your Compose file. This lets you interact with the container without opening a new terminal or restarting it.

Syntax

The basic syntax of docker compose exec is:

• docker compose exec: The command to execute a command inside a running container managed by Docker Compose.
• [service]: The name of the service as defined in your docker-compose.yml file.
• [command]: The command you want to run inside the container.

bash

docker compose exec [service] [command]

Example

This example shows how to run an interactive shell inside a running web service container using docker compose exec. It lets you explore the container's file system or run commands directly.

bash

version: '3.8'
services:
  web:
    image: nginx:alpine
    ports:
      - "8080:80"

# After starting the service with:
# docker compose up -d

# Run an interactive shell inside the 'web' container:
docker compose exec -it web sh

Output

# You will see a shell prompt inside the container, e.g.:
/ # ls
bin   dev   etc   home  lib   media mnt   proc  root  run   sbin  srv   sys   tmp   usr   var

Common Pitfalls

Common mistakes when using docker compose exec include:

• Trying to run exec on a service that is not running. The container must be up.
• Forgetting to use an interactive terminal with -it when running shells or interactive commands.
• Confusing docker compose exec with docker compose run, which starts a new container instead of using an existing one.

bash

docker compose exec web sh
# May fail if the container is not running

docker compose exec -it web sh
# Correct way to get an interactive shell

docker compose run web sh
# Starts a new container, not the running one

Quick Reference

Here is a quick cheat sheet for docker compose exec usage:

Command	Description
docker compose exec web ls /app	Run ls /app inside the web container
docker compose exec -it db psql	Open interactive PostgreSQL shell inside db container
docker compose exec api curl http://localhost	Run curl inside api container
docker compose exec -it web sh	Run shell inside web container (interactive)
docker compose exec -u root web sh	Run shell as root user inside web container

Key Takeaways

Use docker compose exec [service] [command] to run commands inside running containers.

Add -it flags for interactive commands like shells.

The service container must be running before using exec.

Do not confuse exec with run; exec uses existing containers.

You can specify user with -u to run commands as different users.