Ubuntu替换国内源

备份sources.list文件

在console中输入sudo cp /etc/apt/sources.list /etc/apt/sources.list.pak进行文件备份

修改sources.list文件

在console中输入sudo vim /etc/apt/sources.list进行文件修改

替换文件内容为以下内容：

# 默认注释了源码仓库，如有需要可自行取消注释
deb https://mirrors.ustc.edu.cn/ubuntu/ xenial main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu/ xenial main main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ xenial-updates main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu/ xenial-updates main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ xenial-security main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu/ xenial-security main restricted universe multiverse

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

中科大源网s站有如下说明：

arm ubuntu开发板的apt的库和普通ubuntu的库是不一样的，arm的是ubuntu-ports库。
所以只要将sources.list文件中的ubuntu 改为ubuntu-port即可，例如：

# 默认注释了源码仓库，如有需要可自行取消注释
deb https://mirrors.ustc.edu.cn/ubuntu-ports/ xenial main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu-ports/ xenial main main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu-ports/ xenial-updates main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu-ports/ xenial-updates main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu-ports/ xenial-backports main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu-ports/ xenial-backports main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu-ports/ xenial-security main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu-ports/ xenial-security main restricted universe multiverse

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

阿里源：

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

可能遇到的问题

Ubuntu换源后，更新提示缺少公钥

可通过sudo apt-key adv指令为其增加公钥，具体如下

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys <缺失的公钥>

这种方案对22.04以下是合理的，但是对22.04及以上版本是不认可的，Ubuntu 不希望您在单个 /etc/apt/trusted.gpg 文件中添加所有签名密钥。它建议使用位于 /etc/apt/trusted.gpg.d 目录中的单独文件。

如果你已经这么做了，你可以尝试：

sudo cp /etc/apt/trusted.gpg /etc/apt/trusted.gpg.d

若您没有这么做，您可以尝试Ubuntu弃用apt-key