ubuntu19更新源

首先查看版本

lsb_release -c
Codename:    eoan

即为eoan版本

下面是163的源

deb http://mirrors.163.com/ubuntu/ eoan main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ eoan-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ eoan-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ eoan-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ eoan-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ eoan main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ eoan-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ eoan-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ eoan-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ eoan-backports main restricted universe multiverse

当然如果第一步获取的版本不是eoan 就把上面的eoan替换成你自己的版本

然后把/etc/apt/sources.list删除 把上面的内容写进去

保存后执行

sudo apt-get update