1.打开终端，输入su和管理员密码但会提示sorry
liuwk@192 ~ % su
Password:
su: Sorry
2.输入sudo su,进入root权限，修改su的密码
liuwk@192 ~ % sudo su
sh-3.2# whoami
root
sh-3.2# passwd root
Changing password for root.
New password:
Retype new password:
3.退出，重新验证，可正常通过刚才设置的密码进入su
sh-3.2# exit
exit
liuwk@192 ~ % whoami
liuwk
liuwk@192 ~ % su
Password:
sh-3.2# whoami
root
