使用以下命令清理残留配置，其实就是删除残留的.rc文件
dpkg -l | grep '^rc' | awk '{print $2}' | sudo xargs dpkg --purge
从手册中得知，remove只会删除软件包本身，不会删除配置文件，而purge会删除所有相关文件，所以，如果确定以后不需要这这些残留配置文件了，优先选择
sudo apt-get purge --auto-remove packagename or sudo apt-get --purge autoremove packagename
From man apt-get:
remove
remove is identical to install except that packages are removed instead of installed. Note
that removing a package leaves its configuration files on the system. If a plus sign is
appended to the package name (with no intervening space), the identified package will be
installed instead of removed.
purge
purge is identical to remove except that packages are removed and purged (any configuration
files are deleted too).
其他参考：
https://askubuntu.com/questions/376253/is-not-installed-residual-config-safe-to-remove-all
