Linux command: Useradd

Useradd Introduction to Commands:

The Useradd command is used to create a user, which is only available to the system Superuser root by default.

1 . command format: useradd [options] Username

Useradd [-C comment] [-D Home_dir]

[-E Expire_date] [-F Inactive_time]

[-G Initial_group] [-G group[,...]]

[-M [-K Skeleton_dir] |-m] [-s Shell]

[-U uid [-O]] [-N] [-R] Login

2. Command function:

account to create or update new user information

3 . Command parameters:

-u uid Specifies the UID of the new user (user ID number)

- G GID (Basic Group) specifies the base group GID (group ID number) for the new user

- g GID,... (Additional group) specifies the new user additional group GID (additional group ID number) Multiple attachment groups can be used, separated by

- C "COMMENT" This option is used to specify the user's description information for easy Administrator Management

-d/path/to/directory Specify a new user's home directory

- s SHELL This option is used to specify the user's shell, which is specified by default if the option is not used/bin/bash

- M - K When creating a new user, copy the configuration document in/etc/skel to the new user's home directory.

-M does not create a home directory when adding new users.

-R Add System user

4 . Command instance:

1. Useradd John add John User

[Email protected] test1]# Useradd John

[[email protected] test1]# passwd John set John user password

Change the user John's password.

New Password:

Re-enter the new password:

PASSWD: All the authentication tokens have been successfully updated.  

[Email protected] test1]# TAIL-N3/ETC/PASSWD

Oprofile:x:16:16:special user account to being used by Oprofile:/home/oprofile:/sbin/nologin

Donggen:x:500:500::/home/donggen:/bin/bash

John:x:501:501::/home/john:/bin/bash user does not specify Uid,gid, and basic groups and attachment groups, default options

2, useradd-u 666-g 500-g 500-c "Test User Management Command user" Tom

[[email protected] test1]# useradd-u 666-g 500-c "Testing User management Commands" Tom

[Email protected] test1]# TAIL-N3/ETC/PASSWD

Donggen:x:500:500::/home/donggen:/bin/bash

John:x:501:501::/home/john:/bin/bash

tom:x:666:500: User to test user administration commands:/home/tom:/bin/bash

[Email protected] test1]# Tail-n3/etc/gshadow

Donggen:!::tom This shows Tom User's attachment group as Donggen

john:!::

tom:!::

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Linux command: Useradd