内容一：添加 Ubuntu 软件源
# cat /etc/apt/sources.list
# Ubuntu sources have moved to /etc/apt/sources.list.d/ubuntu.sources# vim /etc/apt/sources.list.d/ubuntu.sources创建以下内容：
Types: deb
URIs: http://security.ubuntu.com/ubuntu/
Suites: noble-security
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg内容二：添加第 3 方软件源
# cat /etc/apt/sources.list
# Ubuntu sources have moved to /etc/apt/sources.list.d/ubuntu.sources# vim /etc/apt/sources.list.d/ubuntu.sources创建以下内容：
Types: deb
URIs: http://mirrors.aliyun.com/ubuntu/
Suites: noble noble-updates noble-backports
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg（补充：这里以添加阿里云的软件源为例）