2018-03-01 10:01:06
例1：passwd username 直接修改用户的密码
普通用户可以且只能修改自己的密码，root用户可以修改任何人的密码
[root@localhost ~]# passwd chen
Changing password for user chen.
New password:
BAD PASSWORD: it is WAY too short
BAD PASSWORD: is a palindrome
Retype new password:
passwd: all authentication tokens updated successfully.
例2: 明文直接修改用户密码
[root@localhost ~]# echo "afasf" |passwd --stdin chen
Changing password for user chen.
passwd: all authentication tokens updated successfully.
例3：锁定某个用户的密码不能修改（在锁定的情况下，root用户仍然可以修改其密码）
[root@localhost ~]# passwd -l chen
Locking password for user chen.
passwd: Success
[chen@localhost ~]$ passwd
Changing password for user chen.
Changing password for chen.
(current) UNIX password:
passwd: Authentication token manipulation error
例4：解锁某个用户，
命令格式：root执行：passwd -u xxx -u:unlock
[root@localhost ~]# passwd -u chen ------------陈的密码保护被解除
Unlocking password for user chen.
passwd: Success
[root@localhost ~]# su - chen
[chen@localhost ~]$ passwd ------------- 此时输入的密码要求：不能太短和字母和数字组合（root下无此要求）
Changing password for user chen.
Changing password for chen.
(current) UNIX password: ------------- 输入当前的密码
New password:
BAD PASSWORD: it does not contain enough DIFFERENT characters
New password:
Retype new password:
passwd: all authentication tokens updated successfully.