vi source.list 删除全部内容，复制以下内容并保存 阿里云源：
deb http://mirrors.aliyun.com/ubuntu/ eoan main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ eoan-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ eoan-updates main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ eoan-proposed main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ eoan-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ eoan main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ eoan-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ eoan-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ eoan-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ eoan-backports main restricted universe multiverse清华源：
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-updates main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-updates main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-backports main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-backports main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-security main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-security main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-proposed main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-proposed main restricted universe multiverse更新完成后，apt update或apt-get update进行刷新 再执行apt-get upgrade
以下是18.04的阿里云更新源 deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
