docker-useful-commands.md

Docker Useful Commands

docker

docker ps

docker ps - list only running containers

docker ps -a - flag -a is used to list all containers

docker build

Build image from Dockerfile

docker build -t image_name .

docker run

Run container

docker run -d --name container_name image_name

Pass environment variables to docker

Use flag -e or --env to pass specific variables and replace container below:

docker run -it -e TEST=123 --env TEST2=456 --rm container /bin/bash

# Write in terminal
echo $TEST
# Output: 123

Pass environment FILE to docker

Use flag --env-file and replace container below:

docker run -it --env-file ./path/to/env-file <container-id> /bin/bash

Contents of environment file should look like this:

TEST=123
TEST2=456

Run and remove when stopped

Using option --rm will remove container after it is finished.

Replace container below:

docker run -it --rm container /bin/bash

docker exec

Execute command in container

Flags:

• -i: specifies interactive
• t: enables a terminal typing interface

# Logs in to <container-id>
$ docker exec -it <container-id> /bin/bash

docker cp

Copy file from Docker container to local machine

# From local machine's terminal
docker cp container_id:/file/path/within/container /host/path/target

docker logs

See logs from container

docker logs -f <container>

docker stop

Stop all containers

docker stop $(docker ps -q) - stop only active

docker stop $(docker ps -aq) - stop all

docker rm

Remove all containers with status=exited

When running multiple containers, there could be many containers with status=exited.

docker rm $(docker ps -q -f status=exited)

Remove all docker images

docker rmi $(docker images -q) - image should NOT have reference to container

Error - no space left on device

BE CAREFUL when running this, if you want to keep some data:

docker volume rm $(docker volume ls -qf dangling=true)

docker-compose

User docker-compose when running multiple containers using docker-compose.yml:

docker-compose up

Troubleshoot container issues using docker-compose

Replace container below:

docker-compose rm container

If the container is running, you will be informed no stopped containers for that name, so run:

docker-compose stop container

Confirm the prompt by entering y, and then re-build running:

docker-compose up container

Stop, remove containers, remove images and networks what was created by docker-compose up

Replace docker-compose.yml with the name of the docker file in environment:

docker-compose -f docker-compose.yml down --rmi all

Troubleshooting

Access localhost DB from Docker container

Instead of using localhost as DB_HOST, use host.docker.internal.

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