添加PPA软件源后更新的目的。

Question

当使用sudo add-apt-repository ppa:...添加ppa仓库时，为什么要执行sudo apt-get update呢？

我是Ubuntu的新手，我不明白这样做的目的，因为没有从该仓库安装任何软件包。这只会花费很多时间来遍历我的已安装软件包。

- Joren

Answer 1

从manpages中：

update is used to resynchronize the package index files from their sources.
           The indexes of available packages are fetched from the location(s) specified
           in /etc/apt/sources.list. For example, when using a Debian archive, this
           command retrieves and scans the Packages.gz files, so that information about
           new and updated packages is available. An update should always be performed
           before an upgrade or dist-upgrade. Please be aware that the overall progress
           meter will be incorrect as the size of the package files cannot be known in
           advance.

添加apt-add-repository只会在/etc/apt/source.list文件中添加一行。 apt-get update会从所有已知的软件源下载最新的软件包索引。

另外，我建议阅读apt-get维基页面。

- Symin