CentOS免密码切换至root

找到su文件

vim /etc/pam.d/su

将 auth这一列的注释号 去除

# Uncomment the following line to implicitly trust users in the "wheel" group.
auth            sufficient      pam_wheel.so trust use_uid

然后将登陆用户加入 wheel组

usermod -G wheel {xxx}