參考：https://www.daweibro.com/node/142
什么是Ubuntu的軟件源？
我們在使用Debian或者Ubuntu的apt-get工具來安裝需要的軟件時，其實就是從服務器獲取需要安裝的軟件並把它安裝在本地計算機的過程。所謂的軟件源，就是我們獲取軟件的來源，它是定義在/etc/apt/sources.list文件里的。
1. sources.list
sources.list 位於/etc/apt目錄下，是一個普通可編輯的文本文件，保存了ubuntu軟件更新的源服務器的地址。
2. sources.list.d/*.list
sources.list.d/*.list位於/etc/apt/sources.list.d目錄下，為在單獨文件中寫入源的地址提供了一種方式，通常用來安裝第三方的軟件。
3. 換源
首先查看自己的Ubuntu系統的Codename(這一步很重要)，直接導致你更新的源是否對你的系統起效果，查看方法：
lzb@lzb:~$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 16.04.6 LTS Release: 16.04 Codename: xenial
LSB是一套核心標准，它保證了LINUX發行版同LINUX應用程序之間的良好結合。它是 Linux 標准化領域中事實上的標准，制定了應用程序與運行環境之間的二進制接口。這里檢測到LSB，模塊沒有獲取，執行以下語句獲取：
lzb@lzb:~$ sudo apt install lsb-core -y
lzb@lzb:~$ lsb_release -a
LSB Version: core-9.20160110ubuntu0.2-amd64:core-9.20160110ubuntu0.2-noarch:security-9.20160110ubuntu0.2-amd64:security-9.20160110ubuntu0.2-noarch
Distributor ID: Ubuntu
Description: Ubuntu 16.04.6 LTS
Release: 16.04
Codename: xenial
4. 鏡像源獲取
名稱 分類 地址
阿里雲
xenial http://mirrors.aliyun.com/ubuntu/dists/xenial/
xenial-backports http://mirrors.aliyun.com/ubuntu/dists/xenial-backports/
xenial-proposed http://mirrors.aliyun.com/ubuntu/dists/xenial-proposed/
xenial-security http://mirrors.aliyun.com/ubuntu/dists/xenial-security/
xenial-updates http://mirrors.aliyun.com/ubuntu/dists/xenial-updates/
清華
xenial https://mirrors.tuna.tsinghua.edu.cn/ubuntu/dists/xenial
xenial-proposed https://mirrors.tuna.tsinghua.edu.cn/ubuntu/dists/xenial-proposed
xenial-security https://mirrors.tuna.tsinghua.edu.cn/ubuntu/dists/xenial-security
xenial-updates https://mirrors.tuna.tsinghua.edu.cn/ubuntu/dists/xenial-updates
5. 選擇合適的源
lzb@lzb:~$ ping mirrors.aliyun.com PING mirrors.aliyun.com.w.alikunlun.com (117.34.34.236) 56(84) bytes of data. 64 bytes from 117.34.34.236: icmp_seq=1 ttl=54 time=3.91 ms 64 bytes from 117.34.34.236: icmp_seq=2 ttl=54 time=4.18 ms 64 bytes from 117.34.34.236: icmp_seq=3 ttl=54 time=3.68 ms 64 bytes from 117.34.34.236: icmp_seq=4 ttl=54 time=7.89 ms
lzb@lzb:~$ ping mirrors.tuna.tsinghua.edu.cn PING cdnmirrors.s.tuna.tsinghua.edu.cn (101.6.8.193) 56(84) bytes of data. 64 bytes from 101.6.8.193: icmp_seq=1 ttl=241 time=19.4 ms 64 bytes from 101.6.8.193: icmp_seq=2 ttl=241 time=19.8 ms 64 bytes from 101.6.8.193: icmp_seq=3 ttl=241 time=21.4 ms 64 bytes from 101.6.8.193: icmp_seq=4 ttl=241 time=19.6 ms
發現阿里源速度比較快。
6. 備份並修改sources.list
sudo cp /etc/apt/sources.list /etc/apt/sources.beifen.list //備份原來的源信息
這里建立了兩個源的文件，可以根據需要選擇用哪一個。
sudo gedit /etc/apt/sources.qinghua.list //清華源的配置文件
清華源信息：
# 默認注釋了源碼鏡像以提高 apt update 速度，如有需要可自行取消注釋
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security main restricted universe multiverse
# 預發布軟件源，不建議啟用
# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-proposed main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-proposed main restricted universe multiverse
sudo gedit /etc/apt/sources.aliyun.list //阿里源的配置文件
阿里源信息：
#deb cdrom:[Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)]/ xenial main restricted
deb-src http://archive.ubuntu.com/ubuntu xenial main restricted #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial universe
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates universe
deb http://mirrors.aliyun.com/ubuntu/ xenial multiverse
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates multiverse
deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse #Added by software-properties
deb http://archive.canonical.com/ubuntu xenial partner
deb-src http://archive.canonical.com/ubuntu xenial partner
deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial-security universe
deb http://mirrors.aliyun.com/ubuntu/ xenial-security multiverse
sudo cp sources.aliyun.list sources.list //選用阿里源
sudo apt-get update //刷新