[背景]

        在树莓派上安装了Ubuntu24.04, 但是下载源默认是ubuntu官方的源，所以想替换成国内的下载源。但是在修改的过程，发现Ubuntu24.04让使用DEB822的格式配置下载源文件。

[替换过程]

        这里以替换aliyun的源为例，对应arm平台的地址：ubuntu镜像_ubuntu下载地址_ubuntu安装教程-阿里巴巴开源镜像站阿里巴巴开源镜像站为您提供免费的ubuntu下载地址及ubuntu安装教程，ubuntu镜像简介：Ubuntu，是一款基于 Debian Linux 的以桌面应用为主的操作系统，内容涵盖文字处理、电子邮件、软件开发工具和 Web 服务等，可供用户免费下载、使用和分享。Ubuntu 提供了一个健壮、功能丰富的计算环境，既适合家庭使用又适用于商业环境，为用户带来了了尽善尽美的使用体验。阿里巴巴开源镜像站，持续同步 Ubuntu、Ubuntu-ports 等最新版镜像文件，为开发者提供极致的下载体验。阿里巴巴开源镜像站https://developer.aliyun.com/mirror/ubuntu?spm=a2c6h.13651102.0.0.3e221b11IP2lW2        按照以前的流程，应该先备份/etc/apt/source.list, 现在先打开/etc/apt/source.lit, 看到以下内容：

# Ubuntu sources have moved to the /etc/apt/sources.list.d/ubuntu.sources
# file, which uses the deb822 format. Use deb822-formatted .sources files
# to manage package sources in the /etc/apt/sources.list.d/ directory.
# See the sources.list(5) manual page for details.

        根据这个提示， 去查看对应的文件： /etc/apt/sources.list.d/ubuntu.sources， 打开后可以看到格式如下：

Types: deb
URIs: http://ports.ubuntu.com/ubuntu-ports
Suites: noble noble-updates noble-backports
Components: main universe restricted multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

# Ubuntu security updates. Aside from URIs and Suites,
# this should mirror your choices in the previous section.
Types: deb
URIs: http://ports.ubuntu.com/ubuntu-ports
Suites: noble-security
Components: main universe restricted multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

        现在可以直接注释这几行, 或者直接删除这个文件，新增对应源的文件，我现在创建的文件是aliyun.sources, 内容如下：

Types: deb
URIs: https://mirrors.aliyun.com/ubuntu-ports/
# Suites: noble noble-security noble-backports noble-updates noble-proposed
Suites: noble noble-security noble-backports noble-updates
Components:  main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

Types: deb-src
URIs: https://mirrors.aliyun.com/ubuntu-ports/
# Suites: noble noble-security noble-backports noble-updates noble-proposed
Suites: noble noble-security noble-backports noble-updates
Components:  main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

        这里参考官方的格式以及阿里云提供的源格式：

        （1）Types：deb 是指二进制包的位置，deb-src 则是源码包的位置，根据需要分开配置

        （2）URIs：对应下载源的URL, aliyun对应的URL: ubuntu-ports安装包下载_开源镜像站-阿里云

        （3）Suites：通常是版本或者版本加上"-security" "-backports" "-updates"等格式

        （4）Components：按照main restricted universe multiverse格式填写

        （5）Signed-By：按照ubuntu.sources中的复制过来

        【NOTE】Suites, Components等参数都可以按照自己的需求进行修改，并不是要把全部的类型都写上去，按需即可！！！

deb https://mirrors.aliyun.com/ubuntu-ports/ noble main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu-ports/ noble main restricted universe multiverse

deb https://mirrors.aliyun.com/ubuntu-ports/ noble-security main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu-ports/ noble-security main restricted universe multiverse

deb https://mirrors.aliyun.com/ubuntu-ports/ noble-updates main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu-ports/ noble-updates main restricted universe multiverse

# deb https://mirrors.aliyun.com/ubuntu-ports/ noble-proposed main restricted universe multiverse
# deb-src https://mirrors.aliyun.com/ubuntu-ports/ noble-proposed main restricted universe multiverse

deb https://mirrors.aliyun.com/ubuntu-ports/ noble-backports main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu-ports/ noble-backports main restricted universe multiverse

        源文件中对这部分数据的解释：

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.

## Ubuntu distribution repository
##
## The following settings can be adjusted to configure which packages to use from Ubuntu.
## Mirror your choices (except for URIs and Suites) in the security section below to
## ensure timely security updates.
##
## Types: Append deb-src to enable the fetching of source package.
## URIs: A URL to the repository (you may add multiple URLs)
## Suites: The following additional suites can be configured
##   <name>-updates   - Major bug fix updates produced after the final release of the
##                      distribution.
##   <name>-backports - software from this repository may not have been tested as
##                      extensively as that contained in the main release, although it includes
##                      newer versions of some applications which may provide useful features.
##                      Also, please note that software in backports WILL NOT receive any review
##                      or updates from the Ubuntu security team.
## Components: Aside from main, the following components can be added to the list
##   restricted  - Software that may not be under a free license, or protected by patents.
##   universe    - Community maintained packages.
##                 Software from this repository is only maintained and supported by Canonical
##                 for machines with Ubuntu Pro subscriptions. Without Ubuntu Pro, the Ubuntu
##                 community provides best-effort security maintenance.
##   multiverse  - Community maintained of restricted. Software from this repository is
##                 ENTIRELY UNSUPPORTED by the Ubuntu team, and may not be under a free
##                 licence. Please satisfy yourself as to your rights to use the software.
##                 Also, please note that software in multiverse WILL NOT receive any
##                 review or updates from the Ubuntu security team.
##
## See the sources.list(5) manual page for further settings.

         到此， 修改完毕, 使用如下命令跟新下载源：

sudo apt-get update

[其他]

        注： 下方的源仅适用于配置 x86 架构下的 ubuntu系统，如果您的系统为 ARM, PowerPC等其他架构，请按照上方的教程进行配置即可，即ubuntu-ports的源。

        针对X86平台的机器， 更换方式大同小异， 这里提供几个国内的下载源，清华大学源和163源似乎还没有Ubuntu 24.04的源，暂时先提供下边两个吧。

        【USTC】

Types: deb
URIs: https://mirrors.ustc.edu.cn/ubuntu
Suites: noble noble-updates noble-backports
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

Types: deb
URIs: https://mirrors.ustc.edu.cn/ubuntu
Suites: noble-security
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

        【Aliyun】 

Types: deb
URIs: https://mirrors.aliyun.com/ubuntu/
Suites: noble noble-updates noble-backports
Components: main universe restricted multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg

# Ubuntu security updates. Aside from URIs and Suites,
# this should mirror your choices in the previous section.
Types: deb
URIs: https://mirrors.aliyun.com/ubuntu/
Suites: noble-security
Components: main universe restricted multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg