20150825-User, user group management

1. Create user and parameter description

Usage:

Useradd (option) (parameter)

Parameters:

-D: Specify home directory when creating user

-D: Modify the default value when creating a user

-e: Specify the expiration date of the account

-F: Specifies how long a user's password can be used after it expires

-G: Specify the group to which the user belongs

-G: Specify additional groups to which the user belongs

-M: Create User home Directory

-M: Do not create user home directory

-r: Create System account (1-499 or 1-999)

-S: Specifies the shell that is used after the user logs on

-u: Specify user uid

2, modify the user

Usage:

Usermod (option) (parameter)

Parameters:

-D: Specify home directory when creating user

-e: Specify the expiration date of the account

-F: Specifies how long a user's password can be used after it expires

-G: Specify the group to which the user belongs

-G: Specify additional groups to which the user belongs

-S: Specifies the shell that is used after the user logs on

-L: Modify user Name

-L: Lock user

-U: Unlocked

3. Delete users

Usage:

Userdel (option) (parameter)

Parameters:

-F: Force delete

-R: Delete the user and delete the associated files at the same time

4. Create user group and parameter description

Usage:

Groupadd (option) (parameter)

Parameters:

-G: Specify GID for new group

-r: Create a system group (ID between 1-499 1-999)

-O: Allow group to add ID not unique

5, modify the group data

Usage:

Groupmod (option) (parameter)

6. Common examples

3.1, build a user chinamobile, specify the user ID is 10086, use the existing/home/test directory as home directory, do not create a new home directory, the user is valid for 365 days, the default user group is Chinamobile, Additional user group is chinanet (user group already exists)

Useradd chinamobile-u 10086-m-d/home/test-e 365-g chinanet

3.2, create user group CNC, and add user chinamobile to this user group

Groupadd CNC

Usermod-a-G CNC chinamobile

3.3, forcibly delete user deltest, and associated files

Userdel-f-R Deltest

3.4, modify the group name CNC for Wangtong

Groupmod-n Wangtong CNC

20150825-User, user group management