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passwd
Used to allow users to change their passwords
Additional information
passwdThe command is used to set the user's authentication information, including user password, password expiration time, etc. System administrators can use it to manage system user passwords. Only administrators can specify user names, and general users can only change their own passwords.
grammar
passwd [选项] [参数]
Options
-d: Delete the password, only system administrators can use it;-f: Enforcement;-k: The setting can only be updated after the password expires;-l: Lock password;-s: Lists password-related information, which can only be used by system administrators;-u: Unlock a locked account.
parameter
用户名: User name that requires setting password.
knowledge expansion
Files related to user and group account information
Store user information:
/etc/passwd/etc/shadow
Store group information:
/etc/group/etc/gshadow
User information file analysis (separate each item with:)
For example:jack:X:503:504:::/home/jack/:/bin/bash
jack:usernameX: Password, password503: User ID (0 represents root, ordinary new users start from 500)504:group::describe/home/jack/:User home directory/bin/bash:User default Shell
Group information file analysis
For example:jack:$!$:???:13801:0:99999:7:*:*:
jack:group name$!$: Encrypted password13801: The number of days between the creation date and today0: Minimum number of digits in password99999: User password7: Reminder when 7 days are up*: Disabled days*:Expiration days
Example
If you are an ordinary user, passwdyou can only change your own password. If you want to create a password for the new user after creating a new user, use passwdthe user name. Note that you must create it with the permissions of the root user.
[root@localhost ~]# passwd linuxde # 更改或创建linuxde用户的密码；
Changing password for user linuxde.
New UNIX password: # 请输入新密码；
Retype new UNIX password: # 再输入一次；
passwd: all authentication tokens updated successfully. # 成功；
If ordinary users want to change their passwords, passwdthey can run it directly. For example, the current operating user is linuxde.
[linuxde@localhost ~]$ passwd
Changing password for user linuxde. # 更改linuxde用户的密码；
(current) UNIX password: # 请输入当前密码；
New UNIX password: # 请输入新密码；
Retype new UNIX password: # 确认新密码；
passwd: all authentication tokens updated successfully. # 更改成功；
For example, if we prevent a user from changing their password, we can use -lthe option to lock it:
[root@localhost ~]# passwd -l linuxde # 锁定用户linuxde不能更改密码；
Locking password for user linuxde.
passwd: Success # 锁定成功；
[linuxde@localhost ~]$ su linuxde # 通过su切换到linuxde用户；
[linuxde@localhost ~]$ passwd # linuxde来更改密码；
Changing password for user linuxde.
Changing password for linuxde
(current) UNIX password: # 输入linuxde的当前密码；
passwd: Authentication token manipulation error # 失败，不能更改密码；
An example of a recurrence:
[root@localhost ~]# passwd -d linuxde # 清除linuxde用户密码；
Removing password for user linuxde.
passwd: Success # 清除成功；
[root@localhost ~]# passwd -S linuxde # 查询linuxde用户密码状态；
Empty password. # 空密码，也就是没有密码；
注意：当我们清除一个用户的密码时，登录时就无需密码，这一点要加以注意。
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