apt-get update
sudo apt-get install xinit
//查看有没有gdm
dpkg -l|grep gdm
//没有gdm执行这个，当然好像这个不太管用，我的反正是不管用
sudo apt-get install gdm
安装桌面包，很大，得等好久，等就行了
sudo apt-get install kubuntu-desktop
安装桌面软件
sudo apt-get install gnome-core
更新镜像源
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak
网址：https://mirrors.tuna.tsinghua.edu.cn/help/ubuntu/
sudo vi /etc/apt/sources.list
如下是arm架构的配置
# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释 deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ impish main restricted universe multiverse # deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ impish main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ impish-updates main restricted universe multiverse # deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ impish-updates main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ impish-backports main restricted universe multiverse # deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ impish-backports main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ impish-security main restricted universe multiverse # deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ impish-security main restricted universe multiverse # 预发布软件源，不建议启用 # deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ impish-proposed main restricted universe multiverse # deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ impish-proposed main restricted universe multiverse
然后更新软件包缓存：
sudo apt update
通常我们会紧跟着再执行命令：
sudo apt-get upgrade
这个命令，会把本地已安装的软件，与刚下载的软件列表里对应软件进行对比，如果发现已安装的软件版本太低，就会提示你更新
软件包管理器
sudo apt-get install gsynaptic
