在使用orange pi安装了armbian系统后，很多命令都不能安装
如redis和mysql
于是换源
首先备份之前的源 cp /etc/apt/sources.list,.bak}
然后将/etc/apt/sources.list替换为以下内容
```
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch-updates main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch-updates main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch-backports main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch-backports main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian-security/ stretch/updates main contrib non-free
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian-security/ stretch/updates main contrib non-free
```
最后执行`apt-get update`
完成后ffmpeg和mpv可能不能使用
只能再编译安装ffmpeg和安装mpg123替换mpv
