在 shell 中运行命令时（例如 sudo apt-get install aptitude），这是输出：
dpkg: warning: 'ldconfig' not found in PATH or not executable.
dpkg: warning: 'start-stop-daemon' not found in PATH or not executable.
dpkg: 2 expected program(s) not found in PATH or not executable.
NB: root's PATH should usually contain /usr/local/sbin, /usr/sbin and /sbin.
这是我设置的变量：
export PATH=$PATH:/usr/local/sbin:/usr/local/bin in bashrc
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" in /etc/environment
Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" in /etc/sudoerds
echo $path /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/home/node/node:/usr/local/sbin:/usr/local/bin
sudo echo $path
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/home/node/node:/usr/local/sbin:/usr/local/bin