一、提要?

????????在修改国内数据源的时候，切不可以将网上搜索到的文档直接拷贝进/etc/apt/sources.lst文件内，因为数据源和当前的ubuntu版本名称是密切相关的。必须修改成当前版本的名称，才能不出差错。

二、确定当前版本

????????每个版本的源都是不同的，如果源的版本不同就会出现很多的错误，比如gcc缺少依赖项等。

????????查看当前版本指令：

lsb_release -a

No LSB modules are available.
Distributor ID:?? ?Ubuntu
Description:?? ?Ubuntu 20.04.4 LTS
Release:?? ?20.04
Codename:?? ?focal

查看版本的代号和版本

release就是该ubuntu的版本号

codename就是该版本的代号

三、如何修改/etc/apt/sources.list

然后打开源文件：

sudo vim /etc/apt/sources.list

将原来的内容全部删除

将源地址加入进去：

deb http://mirrors.aliyun.com/ubuntu/ codename main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ codename main restricted universe multiverse
?
deb http://mirrors.aliyun.com/ubuntu/ codename-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ codename-security main restricted universe multiverse
?
deb http://mirrors.aliyun.com/ubuntu/ codename-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ codename-updates main restricted universe multiverse
?
deb http://mirrors.aliyun.com/ubuntu/ codename-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ codename-proposed main restricted universe multiverse
?
deb http://mirrors.aliyun.com/ubuntu/ codename-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ codename-backports main restricted universemultiverse

codename就是课该版本的代号，比如说我的是22.04版本的(jammy），我的源就是

deb https://mirrors.ustc.edu.cn/ubuntu/ jammy main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ jammy main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ jammy-updates main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ jammy-updates main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ jammy-backports main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ jammy-backports main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ jammy-security main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ jammy-security main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ jammy-proposed main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ jammy-proposed main restricted universe multiverse

四、修改成国内数据源

?应用版本信息搜索：

lsb_release -a

(base) huatec@huatec-GW:~$ lsb_release -a
No LSB modules are available.
Distributor ID:?? ?Ubuntu
Description:?? ?Ubuntu 20.04.4 LTS
Release:?? ?20.04
Codename:?? ?focal

看到，版本名称是 focal；而数据源与此名要对应；

编辑/etc/apt/sources.list文件, 在文件最前面添加以下条目(操作前请做好相应备份)：

4.1 清华源

# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse

# 预发布软件源，不建议启用
# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse

然后执行命令：

sudo apt-get update
sudo apt-get upgrade

其他几份国内源如下：

4.2 阿里源

deb http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse
?

4.3 中科大源

deb https://mirrors.ustc.edu.cn/ubuntu/ focal main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ focal main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ focal-security main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ focal-security main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse

4.4 网易163源

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

（将以上四个源粘到/etc/apt/sources.lst就可以了。）