可将 http://cn.archive.ubuntu.com/ubuntu/ 替换为下列任意服务器：
- Ubuntu 官方（欧洲，国内较慢，无同步延迟）
- http://archive.ubuntu.com/ubuntu/
- Ubuntu 官方中国（目前是阿里云）
- http://cn.archive.ubuntu.com/ubuntu/
- 网易（广东广州电信/联通千兆双线接入）
- http://mirrors.163.com/ubuntu/
- 搜狐（山东联通千兆接入）
- http://mirrors.sohu.com/ubuntu/
- 阿里云（北京万网/浙江杭州阿里云服务器双线接入）
- http://mirrors.aliyun.com/ubuntu/
- 中国开源软件中心
- http://mirrors.oss.org.cn/ubuntu/
- 首都在线科技
- http://mirrors.yun-idc.com/ubuntu/
- 贝特康姆（江苏常州电信）
- http://centos.bitcomm.cn/ubuntu
- Linux运维派
- https://mirrors.skyshe.cn/ubuntu/
#deb cdrom:[Ubuntu 18.04 LTS _Bionic Beaver_ - Release amd64 (20180426)]/ bionic main restricted # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted # deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted ## Major bug fix updates produced after the final release of the ## distribution. deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted # deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team. Also, please note that software in universe WILL NOT receive any ## review or updates from the Ubuntu security team. deb http://mirrors.aliyun.com/ubuntu/ bionic universe # deb-src http://mirrors.aliyun.com/ubuntu/ bionic universe deb http://mirrors.aliyun.com/ubuntu/ bionic-updates universe # deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates universe ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team, and may not be under a free licence. Please satisfy yourself as to ## your rights to use the software. Also, please note that software in ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http://mirrors.aliyun.com/ubuntu/ bionic multiverse # deb-src http://mirrors.aliyun.com/ubuntu/ bionic multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-updates multiverse # deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates multiverse ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. 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 ## Uncomment the following two lines to add software from Canonical's ## 'partner' repository. ## This software is not part of Ubuntu, but is offered by Canonical and the ## respective vendors as a service to Ubuntu users. # deb http://archive.canonical.com/ubuntu bionic partner # deb-src http://archive.canonical.com/ubuntu bionic partner deb http://security.ubuntu.com/ubuntu bionic-security main restricted # deb-src http://security.ubuntu.com/ubuntu bionic-security main restricted deb http://security.ubuntu.com/ubuntu bionic-security universe # deb-src http://security.ubuntu.com/ubuntu bionic-security universe deb http://security.ubuntu.com/ubuntu bionic-security multiverse # deb-src http://security.ubuntu.com/ubuntu bionic-security multiverse