一、源文件位置

备份并替换/etc/apt/sources.list的源内容：

二、更改源文件内容

    sudo gedit /etc/apt/sources.list

    deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse

    deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse

    deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse

    deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse

    ##测试版源

    deb http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse

    # 源码

    deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse

    deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse

    deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse

    deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse

    ##测试版源

    deb-src http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse

    # Canonical 合作伙伴和附加

    deb http://archive.canonical.com/ubuntu/ xenial partner

    deb http://extras.ubuntu.com/ubuntu/ xenial main