安装/卸载 snapd 时遇到问题。
由于某种原因，我的 Ubuntu 16.04 上的 snap 版本不正确：
snap --version
snap 2.31.1~14.04
snapd unavailable
series -
所以我想使用以下方法手动重新安装 snad：
sudo apt-get install snapd
并得到错误：
Errors were encountered while processing:
/var/cache/apt/archives/snapd_2.33.1~14.04_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
我决定通过尝试使用以下命令来卸载此版本：
sudo apt purge snapd ubuntu-core-launcher squashfs-tools
给我这个结果：
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package 'ubuntu-core-launcher' is not installed, so not removed
The following packages will be REMOVED:
snapd* squashfs-tools*
0 upgraded, 0 newly installed, 2 to …