新安装的Debian系统，经常出现安装不了软件的情况，因为默认的源是国外，所以导致无法安装，我们可以通过修改源的方式进行处理。
1.编辑 /etc/apt/sources.list 文件以修改更新源
vim /etc/apt/sources.list
2.写入如下内容
deb http://mirrors.163.com/debian/ stretch main non-free contrib
deb http://mirrors.163.com/debian/ stretch-updates main non-free contrib
deb http://mirrors.163.com/debian/ stretch-backports main non-free contrib
deb-src http://mirrors.163.com/debian/ stretch main non-free contrib
deb-src http://mirrors.163.com/debian/ stretch-updates main non-free contrib
deb-src http://mirrors.163.com/debian/ stretch-backports main non-free contrib
deb http://mirrors.163.com/debian-security/ stretch/updates main non-free contrib
deb-src http://mirrors.163.com/debian-security/ stretch/updates main non-free contrib
3.保存并获取软件包列表
apt-get update
