# Docker Commands Guide ## Docker Data Directory Docker stores its files, such as images, containers, and volumes, in specific directories. These are essential for Docker's operation. - **`/var/lib/docker/`**: This is Docker's primary data directory where all data related to Docker is stored. - **`/var/lib/docker/containers/`**: Contains the configurations and files for individual Docker containers. - **`/var/lib/docker/volumes/`**: Stores the data for Docker volumes, which allow persistent data storage outside of containers. --- ## Installing Docker on Ubuntu Here’s a step-by-step explanation of the commands used to install Docker on Ubuntu. ```bash # Update the package list and install required packages sudo apt update && sudo apt install -y ca-certificates curl ``` - **`sudo apt update`**: Updates the local package list to ensure you're downloading the latest versions. - **`sudo apt install -y ca-certificates curl`**: Installs essential packages like `ca-certificates` and `curl` for secure communication and downloading files. ```bash # Create a directory for Docker's GPG key and download it sudo install -m 0755 -d /etc/apt/keyrings curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc sudo chmod a+r /etc/apt/keyrings/docker.asc ``` - **`install -m 0755 -d /etc/apt/keyrings`**: Creates the directory `/etc/apt/keyrings` with the correct permissions for storing GPG keys. - **`curl -fsSL -o `**: Downloads Docker’s GPG key securely and stores it as `docker.asc`. - **`chmod a+r`**: Gives read permission to all users for the GPG key file. ```bash # Add Docker's official repository to Apt sources echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null ``` - **`dpkg --print-architecture`**: Determines the system's architecture (e.g., `amd64`). - **`os-release`**: Fetches the OS version to ensure the correct Docker version is downloaded for your system. ```bash # Update the package list and install Docker sudo apt update && sudo apt install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin ``` - **`docker-ce`**: Installs Docker Community Edition. - **`docker-ce-cli`**: Installs the Docker command-line interface. - **`containerd.io`**: Installs Containerd, a container runtime used by Docker. - **`docker-buildx-plugin`**: Installs Docker Buildx, an advanced image builder. - **`docker-compose-plugin`**: Installs Docker Compose, which helps manage multi-container applications. --- ## Docker CLI Commands ### Authentication ```bash docker login ``` - **`docker login`**: Authenticates your Docker CLI with Docker Hub or a private registry by prompting for credentials. --- ### Image Management Image management commands help you interact with Docker images: downloading, saving, loading, and removing images. ```bash docker pull ``` - **`docker pull `**: Downloads a Docker image from the specified repository (e.g., Docker Hub). ```bash docker images ``` - **`docker images`**: Lists all Docker images stored on your system. ```bash docker rmi -f ``` - **`docker rmi -f `**: Forcefully removes a Docker image from your system. Use caution as this will permanently delete the image. ```bash docker save -o

``` - **`docker save -o

`**: Saves a Docker image as a tar archive file. Useful for transferring images. ```bash docker load -i ``` - **`docker load -i `**: Loads a Docker image from a tar archive file. --- ### Container Management These commands allow you to create, run, manage, and remove containers. ```bash docker run

``` - **`docker run `**: Runs a Docker container based on the specified image. Add options for more customization. ```bash docker run -it ``` - **`docker run -it`**: Runs a container in interactive mode with a terminal. ```bash docker run -dit ``` - **`docker run -dit`**: Runs a container in detached mode with a terminal, meaning it runs in the background. ```bash docker exec -it ``` - **`docker exec -it `**: Opens an interactive terminal inside a running container. ```bash docker stop ``` - **`docker stop `**: Stops a running container gracefully. ```bash docker rm ``` - **`docker rm `**: Removes a stopped container. ```bash docker rm -f ``` - **`docker rm -f `**: Forcefully stops and removes a running container. ```bash docker ps -aq ``` - **`docker ps -aq`**: Lists all container IDs, both running and stopped. ```bash docker ps -aq -f status=exited ``` - **`docker ps -aq -f status=exited`**: Lists the container IDs of all stopped (exited) containers. ```bash docker container prune ``` - **`docker container prune`**: Removes all stopped containers. ```bash docker commit

``` - **`docker commit

`**: Creates a new Docker image from an existing container. ```bash docker inspect ``` - **`docker inspect `**: Displays detailed information about a container’s configuration and state. ```bash docker inspect --format '{{ .NetworkSettings.IPAddress }}' ``` - **`docker inspect --format '{{ .NetworkSettings.IPAddress }}' `**: Retrieves the IP address of a specific container. ```bash docker cp

:/ ``` - **`docker cp

:/`**: Copies a file from your local system to a Docker container. ```bash docker cp :/

``` - **`docker cp :/

`**: Copies a file from a Docker container to your local system. ```bash docker stats ``` - **`docker stats`**: Displays a live stream of resource usage statistics for all running containers. ```bash docker build -t :

``` - **`docker build -t :

`**: Builds a Docker image from a Dockerfile located at the specified path. --- ### Volume Management Docker volumes are used to persist data between container restarts. These commands manage those volumes. ```bash docker volume ls ``` - **`docker volume ls`**: Lists all Docker volumes available on your system. ```bash docker volume create ``` - **`docker volume create `**: Creates a new volume with the specified name. ```bash docker volume inspect ``` - **`docker volume inspect `**: Displays detailed information about the specified volume. ```bash docker run -dit --name -v :

``` - **`docker run -v :`**: Runs a container and mounts the specified volume at the given location inside the container. --- ### Network Management These commands help manage Docker networks, enabling containers to communicate with each other. ```bash docker network ls ``` - **`docker network ls`**: Lists all Docker networks on your system. ```bash docker network create ``` - **`docker network create `**: Creates a new Docker network. ```bash docker network create --subnet / --gateway --driver=

``` - **`docker network create --subnet / --gateway --driver=

`**: Creates a custom Docker network with specified settings (subnet, gateway, and driver). ```bash docker run -dit --name --network

``` - **`docker run --network `**: Runs a container and connects it to the specified network. ```bash docker network connect

``` - **`docker network connect `**: Connects an existing container to the specified network. ```bash docker network disconnect

``` - **`docker network disconnect

`**: Disconnects the specified container from the network.