Debian7 和 8 更换可用源，解决apt-get、update等的404错误
1、debian 7.x (wheezy)
编辑/etc/apt/sources.list文件(需要使用sudo), 在文件最前面添加以下条目(操作前请做好相应备份)
deb http://mirrors.aliyun.com/debian/ wheezy main non-free contrib
deb http://mirrors.aliyun.com/debian/ wheezy-proposed-updates main non-free contrib
deb-src http://mirrors.aliyun.com/debian/ wheezy main non-free contrib
deb-src http://mirrors.aliyun.com/debian/ wheezy-proposed-updates main non-free contrib
2、debian 8.x (jessie)
编辑/etc/apt/sources.list文件(需要使用sudo), 在文件最前面添加以下条目(操作前请做好相应备份)
deb http://mirrors.aliyun.com/debian/ jessie main non-free contrib
deb http://mirrors.aliyun.com/debian/ jessie-proposed-updates main non-free contrib
deb-src http://mirrors.aliyun.com/debian/ jessie main non-free contrib
deb-src http://mirrors.aliyun.com/debian/ jessie-proposed-updates main non-free contrib