安装所需的磁盘空间大于删除后释放的磁盘空间:为什么？

Question

我安装了OBS Studio：

sudo apt-get install obs-studio 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  gir1.2-keybinder-3.0 libkeybinder-3.0-0
Use 'sudo apt autoremove' to remove them.
The following additional packages will be installed:
  libfdk-aac0 libluajit-5.1-2 libluajit-5.1-common libxcb-xinerama0
The following NEW packages will be installed:
  libfdk-aac0 libluajit-5.1-2 libluajit-5.1-common libxcb-xinerama0 obs-studio
0 upgraded, 5 newly installed, 0 to remove and 0 not upgraded.
Need to get 3,678 kB of archives.
After this operation, 13.0 MB of additional disk space will be used.
Do you want to continue? [Y/n] 

我决定移除它：

sudo apt-get --purge remove obs-studio Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  gir1.2-keybinder-3.0 libfdk-aac0 libkeybinder-3.0-0 libluajit-5.1-2
  libluajit-5.1-common libxcb-xinerama0
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED:
  obs-studio*
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 11.6 MB disk space will be freed.
Do you want to continue? [Y/n] 

删除它时，我希望释放13.0MB的磁盘空间，因为这是安装所需的，但我却释放了11.6MB的磁盘空间:为什么？

Answer 1

在这里可以找到不同之处：

The following additional packages will be installed:
  libfdk-aac0 libluajit-5.1-2 libluajit-5.1-common libxcb-xinerama0

卸载obs-studio之后，如果没有其他包依赖这些包，这些包应该可以使用apt-get autoremove进行删除。

您还可以运行：

sudo apt-get remove --purge obs-studio libfdk-aac0 libluajit-5.1-2 libluajit-5.1-common libxcb-xinerama0

你应该直接得到原来的尺寸。

Answer 2

因为并不是所有的东西都会被移除。注意，这个包需要安装两个库，其中包括libluajit-5.1-2。在卸载过程中，只有包本身被删除，并且提示您使用autoremove来清除未使用的其他包。重新读取卸载提示。配置文件也可能不会被删除。对于完全删除，有时建议使用--purge选项。

至于为什么要这样做，我只能猜测这是一项保护性功能，因为各种软件都依赖于库和API，所以促进系统管理员手动删除它们是一种明智的检查，因为这正是他们想要的。或者换句话说，为了以防万一，要避免破坏东西。