999999Two simple ways to create an account in one week, did you know?

There are three types of users under Linux: 1. Super user: root has all permissions to the operating system uid0

2. Ordinary users: Ordinary users have limited permissions of the operating system uid500-6000

3. Pseudo user: This is to facilitate system management and meet the requirements of the corresponding system process file owner. It cannot log in to the system uid1--499

Manage user files and basic user information are placed here/etc/passwd. Any user has read permission to it. Only the account is defined and the password is not defined

One line represents a user divided into seven parts

Account name: Password: uid: gid: Related information: User home directory: Class library

The user’s password file /etc/shadow is only readable by root

Username: Password: Last changed: Maximum interval: Minimum interval: Warning time: Inactivity time: Expiration time

0can be changed at any time to 999999 for one week

Two easy ways to create an account

1Add a record in /etc/passwd

2#ueradd user#passwd password (lee user’s affiliated group is admin)

View user information:

Common options for the useradd command are as follows:

-dhome-dir: Specify the home directory.

-edate: The date the account was disabled, in the format: YYYY-MM-DD.

-fdays: The number of days after the password expires before the account is disabled.

-ggroup-name: The group name or GID of the main group to which the user belongs.

-Ggroup-list: A list of affiliated groups to which the user belongs. Multiple items are separated by colons.

-m: If the home directory does not exist, create it.

-M: Do not create the user directory.

-n: Do not create user private groups for users.

-r: Create a system account without a home directory with a UID greater than 500.

-p: Encrypted password.

-s: Specify the user to log in to the Shell, the default is /bin/bash.

-uUID: UID of the specified userlinux sets user group permissionssuse linux, it must be uniquelinux sets user group permissions, and is less than 499

Deletion of user:

User disablement:

User’s Unlock:

Change of user login name:

(If a user is locked, the password will be locked. Linux server configuration and management are all strictly prohibiting users from logging into the system. This method is not only mentioned in the above, so I will not give examples one by one)

Group configuration file/etc/group

Group name group password group id other users

Creation and deletion of groups (deletion of groups is different from that of users)

Creation and deletion of group password

What to do if you really don’t know? View help. Man or --help

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