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