page_title: Introduction to working with Docker page_description: Introduction to working with Docker and Docker commands. page_keywords: docker, introduction, documentation, about, technology, understanding, Dockerfile # An Introduction to working with Docker **Getting started with Docker** > **Note:** > If you would like to see how a specific command > works, check out the glossary of all available client > commands on our [Commands Reference](/reference/commandline/cli). ## Introduction In the [Understanding Docker](understanding-docker.md) section we covered the components that make up Docker, learned about the underlying technology and saw *how* everything works. Now, let's get an introduction to the basics of interacting with Docker. > **Note:** > This page assumes you have a host with a running Docker > daemon and access to a Docker client. To see how to install Docker on > a variety of platforms see the [installation > section](/installation/#installation). ## How to use the client The client provides you a command-line interface to Docker. It is accessed by running the `docker` binary. > **Tip:** > The below instructions can be considered a summary of our > [interactive tutorial](https://www.docker.io/gettingstarted). If you > prefer a more hands-on approach without installing anything, why not > give that a shot and check out the > [tutorial](https://www.docker.io/gettingstarted). The `docker` client usage is pretty simple. Each action you can take with Docker is a command and each command can take a series of flags and arguments. # Usage: [sudo] docker [flags] [command] [arguments] .. # Example: $ docker run -i -t ubuntu /bin/bash ## Using the Docker client Let's get started with the Docker client by running our first Docker command. We're going to use the `docker version` command to return version information on the currently installed Docker client and daemon. # Usage: [sudo] docker version # Example: $ docker version This command will not only provide you the version of Docker client and daemon you are using, but also the version of Go (the programming language powering Docker). Client version: 0.8.0 Go version (client): go1.2 Git commit (client): cc3a8c8 Server version: 0.8.0 Git commit (server): cc3a8c8 Go version (server): go1.2 Last stable version: 0.8.0 ### Seeing what the Docker client can do We can see all of the commands available to us with the Docker client by running the `docker` binary without any options. # Usage: [sudo] docker # Example: $ docker You will see a list of all currently available commands. Commands: attach Attach to a running container build Build a container from a Dockerfile commit Create a new image from a container's changes . . . ### Seeing Docker command usage You can also zoom in and review the usage for specific Docker commands. Try typing Docker followed with a `[command]` to see the usage for that command: # Usage: [sudo] docker [command] [--help] # Example: $ docker attach Help output . . . Or you can also pass the `--help` flag to the `docker` binary. $ docker images --help This will display the help text and all available flags: Usage: docker attach [OPTIONS] CONTAINER Attach to a running container --no-stdin=false: Do not attach stdin --sig-proxy=true: Proxify all received signal to the process (even in non-tty mode) ## Working with images Let's get started with using Docker by working with Docker images, the building blocks of Docker containers. ### Docker Images As we've discovered a Docker image is a read-only template that we build containers from. Every Docker container is launched from an image. You can use both images provided by Docker, such as the base `ubuntu` image, as well as images built by others. For example we can build an image that runs Apache and our own web application as a starting point to launch containers. ### Searching for images To search for Docker image we use the `docker search` command. The `docker search` command returns a list of all images that match your search criteria, together with some useful information about that image. This information includes social metrics like how many other people like the image: we call these "likes" *stars*. We also tell you if an image is *trusted*. A *trusted* image is built from a known source and allows you to introspect in greater detail how the image is constructed. # Usage: [sudo] docker search [image name] # Example: $ docker search nginx NAME DESCRIPTION STARS OFFICIAL TRUSTED dockerfile/nginx Trusted Nginx (http://nginx.org/) Build 6 [OK] paintedfox/nginx-php5 A docker image for running Nginx with PHP5. 3 [OK] dockerfiles/django-uwsgi-nginx Dockerfile and configuration files to buil... 2 [OK] . . . > **Note:** > To learn more about trusted builds, check out > [this](http://blog.docker.io/2013/11/introducing-trusted-builds) blog > post. ### Downloading an image Once we find an image we'd like to download we can pull it down from [Docker.io](https://index.docker.io) using the `docker pull` command. # Usage: [sudo] docker pull [image name] # Example: $ docker pull dockerfile/nginx Pulling repository dockerfile/nginx 0ade68db1d05: Pulling dependent layers 27cf78414709: Download complete b750fe79269d: Download complete . . . As you can see, Docker will download, one by one, all the layers forming the image. ### Listing available images You may already have some images you've pulled down or built yourself and you can use the `docker images` command to see the images available to you locally. # Usage: [sudo] docker images # Example: $ docker images REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE myUserName/nginx latest a0d6c70867d2 41 seconds ago 578.8 MB nginx latest 173c2dd28ab2 3 minutes ago 578.8 MB dockerfile/nginx latest 0ade68db1d05 3 weeks ago 578.8 MB ### Building our own images You can build your own images using a `Dockerfile` and the `docker build` command. The `Dockerfile` is very flexible and provides a powerful set of instructions for building applications into Docker images. To learn more about the `Dockerfile` see the [`Dockerfile` Reference](/reference/builder/) and [tutorial](https://www.docker.io/learn/dockerfile/). ## Working with containers ### Docker Containers Docker containers run your applications and are built from Docker images. In order to create or start a container, you need an image. This could be the base `ubuntu` image or an image built and shared with you or an image you've built yourself. ### Running a new container from an image The easiest way to create a new container is to *run* one from an image using the `docker run` command. # Usage: [sudo] docker run [arguments] .. # Example: $ docker run -d --name nginx_web nginx /usr/sbin/nginx 25137497b2749e226dd08f84a17e4b2be114ddf4ada04125f130ebfe0f1a03d3 This will create a new container from an image called `nginx` which will launch the command `/usr/sbin/nginx` when the container is run. We've also given our container a name, `nginx_web`. When the container is run Docker will return a container ID, a long string that uniquely identifies our container. We use can the container's name or its string to work with it. Containers can be run in two modes: * Interactive; * Daemonized; An interactive container runs in the foreground and you can connect to it and interact with it, for example sign into a shell on that container. A daemonized container runs in the background. A container will run as long as the process you have launched inside it is running, for example if the `/usr/bin/nginx` process stops running the container will also stop. ### Listing containers We can see a list of all the containers on our host using the `docker ps` command. By default the `docker ps` command only shows running containers. But we can also add the `-a` flag to show *all* containers: both running and stopped. # Usage: [sudo] docker ps [-a] # Example: $ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 842a50a13032 $ dockerfile/nginx:latest nginx 35 minutes ago Up 30 minutes 0.0.0.0:80->80/tcp nginx_web ### Stopping a container You can use the `docker stop` command to stop an active container. This will gracefully end the active process. # Usage: [sudo] docker stop [container ID] # Example: $ docker stop nginx_web nginx_web If the `docker stop` command succeeds it will return the name of the container it has stopped. > **Note:** > If you want you to more aggressively stop a container you can use the > `docker kill` command. ### Starting a Container Stopped containers can be started again. # Usage: [sudo] docker start [container ID] # Example: $ docker start nginx_web nginx_web If the `docker start` command succeeds it will return the name of the freshly started container. ## Next steps Here we've learned the basics of how to interact with Docker images and how to run and work with our first container. ### Understanding Docker Visit [Understanding Docker](understanding-docker.md). ### Installing Docker Visit the [installation](/installation/#installation) section. ### Get the whole story [https://www.docker.io/the_whole_story/](https://www.docker.io/the_whole_story/)