國內(nèi)有很多Ubuntu的鏡像源,，包括阿里的、網(wǎng)易的,，還有很多教育網(wǎng)的源,，比如：清華源、中科大源,。
我們這里以清華源為例講解如何修改Ubuntu 18.04里面默認的源,。

1、輸入命令修改sources.list文件，當(dāng)然需要超級權(quán)限,，所以要加sudo,；

sudo gedit /etc/apt/sources.list


編輯/etc/apt/sources.list文件

2、在文件最前面添加以下條目(操作前請做好相應(yīng)備份)：

deb https://mirrors.tuna./ubuntu/ bionic main restricted universe multiverse
deb-src https://mirrors.tuna./ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.tuna./ubuntu/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.tuna./ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.tuna./ubuntu/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.tuna./ubuntu/ bionic-backports main restricted universe multiverse
deb https://mirrors.tuna./ubuntu/ bionic-security main restricted universe multiverse
deb-src https://mirrors.tuna./ubuntu/ bionic-security main restricted universe multiverse
deb https://mirrors.tuna./ubuntu/ bionic-proposed main restricted universe multiverse
deb-src https://mirrors.tuna./ubuntu/ bionic-proposed main restricted universe multiverse

3,、修改完成后,，保存文件，警告什么的都不理,，然后運行下面的命令,。

sudo apt-get update
sudo apt-get upgrade


4、到此完成國內(nèi)源更新,。

附加其他源內(nèi)容,，需要的自己添加進sources.list文件里面就ok了。

阿里源：

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


中科大

deb https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse


163源

deb http://mirrors.163.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ bionic-backports main restricted universe multiverse


Ubuntu 18.04 在系統(tǒng)設(shè)置里面是找不到軟件源設(shè)置界面按鈕的（找了好久都沒找到T-T）,，所以需要一些指令幫助啟動圖形界面以便設(shè)置軟件源,。
1、輸入命令

sudo update-manager -c -d


2,、會彈出Software Updater提示框,，這就好辦了，點擊左下角Settings…按鈕,，久違的軟件源設(shè)置就會出來啦,。