Linux User Management-user account management

First, the user account of the increase, delete, change, check

1> Add user------Useradd

Note: 1, user name should not be a pure number or start with a number

2. Change the login shell to/sbin/nologin to prevent users from logging in

Format: useradd [options] User name

Common Command Options

-U: Set UID tag number

-D: Specify the user's host directory, the default value is/home/' user name '

-G: Specify the user's base group

-G: Specify additional groups for users

-e: Specify the user's expiration time

-M: Do not establish and initialize the host directory for the user

-S: Specify the user's login shell

Practice:

1) Create account stu01, host directory set to/OPT/STU01

[[Email protected] ~] #useradd-D/opt/stu01 stu01

2) Create account Stu02,uid 10001, account expires in 2018-06-30, base group is set to Stu01

[[email protected] ~]#useradd-u 10001-e 2018-6-30-g stu01 stu02

[[email protected] ~]# ID stu02
uid=10001 (stu02) gid=502 (stu01) groups=502 (stu01)

　　Command: ID user name---View the user's owning information

2> Set Password------passwd

Format: passwd [options] User name

　　Note: 1, the root user can modify any user's password

2. All users can modify their own password

Common Command Options

-D clears the user's password so that the user can log on without a password

-L lock user account, that is, users cannot log in "shadow in the corresponding password string before adding two exclamation mark!! 】

-S View the user account status, that is, whether it is locked

Stu01 LK 2017-08-25 0 99999 7-1 (Password locked.) "Account is locked"

Stu01 PS 2017-08-25 0 99999 7-1 (Password set, MD5 crypt.) "Account is unlocked"

-U Unlock user account "Two exclamation marks added before password string when clearly locked"

--stdin getting the password from standard input

Practice:

1) Set password to stu01 for stu01 operation from standard input to Redhat

[Email protected] ~]# echo ' Redhat ' | passwd--stdin stu01

3> Modifying an existing user------Usermod

Format: usermod [options] User name

Common options

-L CHANGE the user's login name

-L Lock user account "Add 1 exclamation marks before the corresponding cipher string in shadow!" 】

-U Unlocks user account "exclamation mark added when unlocking"

-u-d-e-g-g-s Same as Useradd command

4> Password Expiration control------chage

Format: chage [options] User name

Common commands: chage-d 0 user name "Allow user to change password at first logon"

-l list Password expiration information

-e Specify the account expiration time Yy-mm-dd

-i specifies how many days to lock the account when the password expires

-m specifies the minimum number of days for password invalidation

-m Specifies the maximum number of days the password expires

5> Delete User------Userdel

Format: Userdel [options] User name

Userdel User Name "Delete user account only does not delete the host directory, mail files and other data"

Userdel-r User Name "Delete user all data"

6> view------ID of the user ID

View the user's own identity: ID

To view the identity of the specified user: ID user name

Only the identity of the private group is listed: ID-G user name, ID-GN user name

Only public groups with identity: Id-g user name, ID-GN user name

-N Identifies display name

Linux User Management-user account management