每当我尝试使用终端安装或删除某些东西时，它都会给出以下错误消息：
bluebird@bluebird:~$ sudo apt-get update
sudo: /usr/lib/sudo/sudoers.so must be only be writable by owner
sudo: fatal error, unable to load plugins
bluebird@bluebird:~$ sudo apt-get remove vlc
sudo: /usr/lib/sudo/sudoers.so must be only be writable by owner
sudo: fatal error, unable to load plugins
bluebird@bluebird:~$ sudo apt-get install apt-file
sudo: /usr/lib/sudo/sudoers.so must be only be writable by owner
sudo: fatal error, unable to load plugins