Debian/Ubuntu
    Debian和Ubuntu都是目前较为流行的Debian系的服务器操作系统，在Docker Hub上都可以直接搜索到官方版。


  搜索Debian
    --------------------------------------------------------------------
    [docker@localhost]$ sudo docker search debian
    INDEX       NAME                                          DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
    docker.io   docker.io/ubuntu                              Ubuntu is a Debian-based Linux operating s...   7868      [OK]       
    docker.io   docker.io/debian                              Debian is a Linux distribution that's comp...   2626      [OK]       
    docker.io   docker.io/google/debian                                                                       53                   [OK]
    docker.io   docker.io/arm32v7/debian                      Debian is a Linux distribution that's comp...   36                   
    docker.io   docker.io/armhf/debian                        Debian is a Linux distribution that's comp...   31                   
    docker.io   docker.io/itscaro/debian-ssh                  debian:jessie                                   23                   [OK]
    ...
    --------------------------------------------------------------------
    
  搜索Ubuntu
    Ubuntu相关的镜像有很多，因此这里使用【-s】参数，只搜索那些被收藏10次以上的镜像。
    --------------------------------------------------------------------
    [docker@localhost ~]$ sudo docker search -s 10 ubuntu
    INDEX       NAME                                                             DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
    docker.io   docker.io/ubuntu                                                 Ubuntu is a Debian-based Linux operating s...   7868      [OK]       
    docker.io   docker.io/dorowu/ubuntu-desktop-lxde-vnc                         Ubuntu with openssh-server and NoVNC            190                  [OK]
    docker.io   docker.io/rastasheep/ubuntu-sshd                                 Dockerized SSH service, built on top of of...   156                  [OK]
    docker.io   docker.io/ansible/ubuntu14.04-ansible                            Ubuntu 14.04 LTS with ansible                   93                   [OK]
    docker.io   docker.io/ubuntu-upstart                                         Upstart is an event-based replacement for ...   87        [OK]       
    docker.io   docker.io/neurodebian                                            NeuroDebian provides neuroscience research...   50        [OK]       
    docker.io   docker.io/ubuntu-debootstrap                                     debootstrap --variant=minbase --components...   38        [OK]       
    docker.io   docker.io/1and1internet/ubuntu-16-nginx-php-phpmyadmin-mysql-5   ubuntu-16-nginx-php-phpmyadmin-mysql-5          36                   [OK]
    docker.io   docker.io/nuagebec/ubuntu                                        Simple always updated Ubuntu docker images...   23                   [OK]
    docker.io   docker.io/tutum/ubuntu                                           Simple Ubuntu docker images with SSH access     18                   
    docker.io   docker.io/i386/ubuntu                                            Ubuntu is a Debian-based Linux operating s...   13                   
    docker.io   docker.io/ppc64le/ubuntu                                         Ubuntu is a Debian-based Linux operating s...   12                   
    docker.io   docker.io/1and1internet/ubuntu-16-apache-php-7.0                 ubuntu-16-apache-php-7.0                        10                   [OK]
    --------------------------------------------------------------------
    根据搜索出来的结果，用户可以自行选择下载镜像并使用。
    
    下面就以Ubuntu15.10为例，让我们进去一个Docker版的Ubuntu:15.10操作系统来体验一下。
    
    使用【-ti】参数进入，查看Ubuntu的版本号：
    --------------------------------------------------------------------
    [docker@localhost ~]$ sudo docker run -ti ubuntu:15.10 /bin/bash
    root@306a1f080fc5:/# cat /etc/os-release 
    NAME="Ubuntu"
    VERSION="15.10 (Wily Werewolf)"
    ID=ubuntu
    ID_LIKE=debian
    PRETTY_NAME="Ubuntu 15.10"
    VERSION_ID="15.10"
    HOME_URL="http://www.ubuntu.com/"
    SUPPORT_URL="http://help.ubuntu.com/"
    BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
    --------------------------------------------------------------------
    当我们试图安装一个curl软件的时候，会提示：Unable to locate package curl。因为，Docker镜像为了精简镜像容量，默认删除了这些信息，需要我们使用apt-get update命令更新一次，大家也可以自己编辑/etc/apt/sources.list文件，将默认的软件源更改为国内的源：  
    --------------------------------------------------------------------
    root@2c3967885444:/# apt-get install curl
    Reading package lists... Done
    Building dependency tree       
    Reading state information... Done
    E: Unable to locate package curl
    --------------------------------------------------------------------
    更新源之后就可以安装软件了：
    --------------------------------------------------------------------
    root@2c3967885444:/# apt-get update
    Ign http://archive.ubuntu.com vivid InRelease
    Ign http://archive.ubuntu.com vivid-updates InRelease
    Ign http://archive.ubuntu.com vivid-security InRelease
    Ign http://archive.ubuntu.com vivid Release.gpg
    Ign http://archive.ubuntu.com vivid-updates Release.gpg
    Ign http://archive.ubuntu.com vivid-security Release.gpg
    Ign http://archive.ubuntu.com vivid Release
    Ign http://archive.ubuntu.com vivid-updates Release
    Ign http://archive.ubuntu.com vivid-security Release
    ...
    root@2c3967885444:/# apt-get install curl
    Reading package lists... Done
    Building dependency tree       
    Reading state information... Done
    ...
    root@2c3967885444:/# curl 
    curl: try 'curl --help' or 'curl --manual' for more information
    --------------------------------------------------------------------
    接下来，我们来用curl访问百度网站(注意，这里我的是可以访问外网，如果有同学不能访问外网，可以安装apache来测试)。
    --------------------------------------------------------------------
    root@172e3d6f55b3:~# curl www.baidu.com
    <!DOCTYPE html>
    <!--STATUS OK--><html> <head><meta http-equiv=content-type content=text/html;charset=utf-8><meta http-equiv=X-UA-Compatible content=IE=Edge><meta content=always name=referrer><link rel=stylesheet type=text/css href=http://s1.bdstatic.com/r/www/cache/bdorz/baidu.min.css><title>百度一下，你就知道</title></head> <body link=#0000cc> <div id=wrapper> <div id=head> <div class=head_wrapper> <div class=s_form> <div class=s_form_wrapper> <div id=lg> <img hidefocus=true src=//www.baidu.com/img/bd_logo1.png width=270 height=129> </div> 
    ...
    --------------------------------------------------------------------