sources.list

deb http://mirrors.cernet.edu.cn/ubuntu/ jammy main restricted universe multiverse
# deb-src http://mirrors.cernet.edu.cn/ubuntu/ jammy main restricted universe multiverse
deb http://mirrors.cernet.edu.cn/ubuntu/ jammy-updates main restricted universe multiverse
# deb-src http://mirrors.cernet.edu.cn/ubuntu/ jammy-updates main restricted universe multiverse
deb http://mirrors.cernet.edu.cn/ubuntu/ jammy-backports main restricted universe multiverse
# deb-src http://mirrors.cernet.edu.cn/ubuntu/ jammy-backports main restricted universe multiverse

# kill security to speed up
# deb http://security.ubuntu.com/ubuntu/ jammy-security main restricted universe multiverse
# deb-src http://security.ubuntu.com/ubuntu/ jammy-security main restricted universe multiverse

# kill proposed to speed up
# deb http://mirrors.cernet.edu.cn/ubuntu/ jammy-proposed main restricted universe multiverse
# deb-src http://mirrors.cernet.edu.cn/ubuntu/ jammy-proposed main restricted universe multiverse