打开终端，输入：sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak
1.继续输入：sudo gedit /etc/apt/sources.list；或者 sudo vim /etc/apt/sources.list
2.输入上面命令后会打开一个TXT文本文档，对此文件进行编辑；
3.删除文档里原来内容，复制下面任意一个源，保存；
4.修改源后，更新软件列表和软件。
sudo apt update
sudo apt upgrade
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#163
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原文：https://www.cnblogs.com/dzwclimber/p/15086922.html