Docker Basic Commands

Table of Contents

``` * Pull an image with the tag ``` docker pull :tag ``` * Pull all tags of an image ``` docker pull -a ``` ### Push an image To pull an image to [Docker Hub](https://hub.docker.com/): * Push an image ``` docker push ``` * Push an image with the tag ``` docker push :tag ``` * Push all tags of an image ``` docker pull -a ``` ### Inspect and pull an image with GHCR * Inspect the docker image ``` docker inspect ghcr.io//: ``` * Pull the docker image ``` docker pull ghcr.io//: ``` ### See a docker image (no download) If you want to see a docker image without downloading the image itself, you can use Quay's [Skopeo tool](https://github.com/containers/skopeo), a command line utility that performs various operations on container images and image repositories. ``` docker run --rm quay.io/skopeo/stable list-tags docker://ghcr.io// ``` Make sure to write the proper information for the repository and the image. To install Skopeo, read [this documentation](install.md). ### Build a container Use **docker build** to build a container based on a Dockerfile * Build a container based on current directory Dockerfile ``` docker build . ``` * Build a container and store the image with a given name * Template ``` docker build -t ":" ``` * Example ``` docker build -t newimage:latest ``` * Build a docker container without using the cache ``` docker build --no-cache ``` ### List all available docker images ``` docker images ``` ### Run a container To run a container based on an image, use the command **docker run**. * Run an image ``` docker run ``` * Run an image in the background (run and detach) ``` docker run -d ``` * Run an image with CLI input ``` docker run -it ``` You can combine arguments, e.g. **docker run -itd**. You can also specify the shell, e.g. **docker run -it /bin/bash** ### Run a new command in an existing container To run a new command in an existing container, use **docker exec**. * Execute interactive shell on the container ``` docker exec -it sh ``` ### Bash shell into container * Bash shell into a container ``` docker exec -i -t /bin/bash ``` * Bash shell into a container with root ``` docker exec -i -t -u root /bin/bash ``` Note: if bash is not available, you can use `/bin/sh` ### Pass arguments with a bash script and a Dockerfile You can do the following to pass arguments with a bash script and a Dockerfile. ```sh # script_example.sh #!/bin/sh echo This is the domain: $env_domain echo This is the name: $env_name echo This is the password: $env_password ``` * File `Dockerfile` ```Dockerfile FROM ubuntu:latest ARG domain ARG name ARG password ENV env_domain $domain ENV env_name $name ENV env_password $password COPY script_example.sh . RUN chmod +x /script_example.sh CMD ["/script_example.sh"] ``` ### Copy files from a container to the local computer ``` docker cp : ``` ### Delete all the containers, images and volumes * To delete all containers: ``` docker compose rm -f -s -v ``` * To delete all images: ``` docker rmi -f $(docker images -aq) ``` * To delete all volumes: ``` docker volume rm $(docker volume ls -qf dangling=true) ``` * To delete all containers, images and volumes: ``` docker compose rm -f -s -v && docker rmi -f $(docker images -aq) && docker volume rm $(docker volume ls -qf dangling=true) ``` ### Kill all the Docker processes * To kill all processes: ``` killall Docker && open /Applications/Docker.app ``` ### Output full logs for all containers The following command output the full logs for all containers in the file **containers.log**: ``` docker compose logs > containers.log ``` ## Resources Usage ### Examine containers with size ``` docker ps -s ``` ### Examine disks usage * Basic mode ``` docker system df ``` * Verbose mode ``` docker system df -v ``` ## Wasted Resources ### Prune the Docker logs ``` docker system prune ``` ### Prune the Docker containers You can use the prune function to delete all stopped containers: ``` docker container prune ``` ### Remove unused and untagged local container images The following is useful if you want to clean up local filesystem: ``` docker image prune ``` ### Clean up and delete all unused container images ``` docker image prune -a ``` ### Clean up container images based on a given timeframe To clean up container images created X hours ago, you can use the following template (replace with a number): ``` docker image prune -a --force --filter "until=h" ``` To clean up container images created before a given date, you can use the following template (replace with the complete date): ``` docker image prune -a --force --filter "until=" ``` Note: An example of a complete date would be `2023-01-04T00:00:00` ## Command Combinations ### Kill all running containers ``` docker kill $(docker ps -q) ``` ### Stop all running containers ``` docker stop $(docker ps -a -q) ``` ### Delete all stopped containers ``` docker rm $(docker ps -a -q) ``` ### Delete all images ``` docker rmi $(docker images -q) ``` ### Update and stop a container in a crash-loop ``` docker update –restart=no && docker stop ``` ## References * Docker Manual - https://docs.docker.com/ * Code Notary - https://codenotary.com/blog/extremely-useful-docker-commands