更新和升级有什么区别？

Question

在apt-get命令中,更新和升级的主要影响是什么？除了措辞之外,我没有看到任何差异.似乎更新是关于系统包,而升级是关于软件包.如果是这种情况,如何判断哪个是系统包,哪个是软件包？

Answer 1

从 man apt

  update
      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...

...

  upgrade
      upgrade is used to install the newest versions of all packages
      currently installed on the system from the sources enumerated in
      /etc/apt/sources.list. Packages currently installed with new

简单来说:apt-get update将更新apt的数据库,可用包列表(以及版本的日期和编号).当apt-get dist-upgrade将升级安装在系统(...如果日期和/或版本不同)的所有包.