Ubuntu18.04 source.list怎么更新国内源

要更新Ubuntu 18.04的软件源为国内源，可以按照以下步骤进行操作：

1. 打开终端，通过以下命令备份当前的软件源列表文件：

sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak 

2. 编辑软件源列表文件，使用以下命令打开编辑器：

sudo nano /etc/apt/sources.list 

3. 在打开的文件中，删除所有内容，然后粘贴以下内容，这是一个推荐的国内源列表：

# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释 # deb-src http://archive.ubuntu.com/ubuntu/ bionic main restricted  # 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释 deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted # deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted  deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted # deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted  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  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  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  # 预发布软件源，不建议启用 # deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse # deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse  deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted # deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted deb http://mirrors.aliyun.com/ubuntu/ bionic-security universe # deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security universe deb http://mirrors.aliyun.com/ubuntu/ bionic-security multiverse # deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security multiverse 

4. 保存更改并关闭编辑器。对于Nano编辑器，请按Ctrl + X，然后按Y，最后按Enter保存文件。

5. 运行以下命令更新软件源：

sudo apt update 

现在，您的Ubuntu 18.04系统的软件源已更新为国内源。您可以使用apt命令安装和更新软件包，速度应该会更快。