Linux系统分支之Ubuntu

1）切换镜像源

本身的镜像都是国外的，下载依赖包太慢， 需要替换成国内镜像地址

国内镜像源推荐
阿里 OPSX 源： https://opsx.alibaba.com/mirror
网易 163 源： http://mirrors.163.com/
中科大 USTC 源： https://mirrors.ustc.edu.cn/
清华 TUNA 源： https://mirrors.tuna.tsinghua.edu.cn/
ubuntu 中国官方源（搜狐）： http://mirrors.sohu.com/help/ubuntu.html

1. 需要修改/etc/apt/sources.list文件内容来修改apt源

首先备份文件
cd /etc/apt/
cp sources.list sources.list.bak

2.修改sources.list文件内容
deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse


3.更新apt本地索引
apt-get update

常见问题：

 1.使用apt-get update 更新的时候发生错误  

Ubuntu 20.04 GPG error: The following signatures couldn't be verified

  原因：这是因为尝试包含第三方包失败，需要进行导入操作

解决：

1.W: GPG error: http://pkg.jenkins-ci.org/debian binary/ Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY FCEF32E745F2C3D5
E: The repository 'http://pkg.jenkins-ci.org/debian binary/ Release' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

找到PUBKEY  : FCEF32E745F2C3D5

2.导入密钥
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys  FCEF32E745F2C3D5

3.apt-key  list   查看当前导入的key