中国科学技术大学

官方教程: http://mirrors.ustc.edu.cn/help/ubuntu.html

sed -i 's/archive.ubuntu.com/mirrors.ustc.edu.cn/g' /etc/apt/sources.list;
sed -i 's/security.ubuntu.com/mirrors.ustc.edu.cn/g' /etc/apt/sources.list;

报错

Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification.

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Certificate verification failed: The certificate is NOT trusted.解决方案_赵宗义11的博客-CSDN博客_certificate is not trusted