User and Rights Management for Linux

Welcome everyone to my blog, first of all declare this article is my * * *, if the text is inappropriate, but also please the predecessors of the great God a lot of advice, niche here first thanked. Life always has all kinds of unhappy, for me the immediate is the best arrangement; to be honest, I don't really like software. This major, I am a liberal arts man, the software world of troughs for me to walk really some difficulty, came to the university inexplicably into this profession, became it the sea a small stone. There is no way, improvise clear, only a head-on to show my generation spirit AH; graduated from university I this small stone quirks contact with the software operation and maintenance of the industry, with a full of confidence with a bright future I joined the Army of Linux training. It was not just two weeks of study and I started my first blog post in my life. Well, the big home and I this child shoes to understand Linux users and Rights Management!

First, Linux users can be divided into the following areas:

2. User:

   A user is a collection of permissions that can obtain system resources.

4. Linux User Group categories:

   (1) Administrator root: Users who use all the privileges of the system, (UID 0)

   (2) Ordinary users: that is, the general user, the specific use of restricted access; (UID 1-65635)

   (3) System users: Protect the system operation of the user, the General people without password can not login. (UID is 1-499)

6. User groups

   User group Categories:

   (1) Normal user group: can add multiple users

   (2) System user group: Add only some system users

   (3) Private group (that is, basic group): When the user is created, if the owning group is not specified for it, a private user group is defined for it, with the name of the user group; (Note: Private groups can become normal user groups, and when other users are added to the group, they become normal groups)

8. Groups are containers for permissions

   For example, a normal user can inherit the permissions of the group to which it belongs.

10. Files related to the group:/etc/group,/etc/gshadow

    /etc/group File: its format: group_name:passwoerd:GID:user_list

Group_name: Group Name

Passwoerd: Group Password

GID: ID number of the group

User_list: List of users with group_name as additional groups

6. User-related files/etc/passwd,/etc/shadow

A /etc/passwd file:

Its format: Account:password:UID:GID:GECOS:diretory:shell

Account: Username or username

Password: User password placeholder

UID: ID number of the user

GID: ID number of the group in which the user is located

GECOS: Details of the user (e.g. name, age, telephone, etc.)

Diretory: User's home directory

Shell: The programming environment in which the user resides

b /etc/shadow

Its format: Account:password: The date of the most recent password change: The number of days the password cannot be changed: the number of days the password needs to be re-modified: The warning period before the password change: grace period for password expiration: Account expiration Date: Reserved.

7. Modify the user and user group commands: useradd,usermod, Groupdd,userdel

A Add User: Useradd [options] Username

Options

1. -u:uid

2. -g:gid

3. -D: Specify user home directory, default is/home/username

4. -S: Specifies the shell environment in which the user resides

5. -G: Specify additional groups for users

For example, add a user maedu. UID is 1234 directories/home/oracle,shell to/bin/sh

#useradd –u 1234–d/home/oracle–s/bin/sh maedu

b Modify User: Usermod [options] Username

Options

1. -u:uid

2. -g:gid

3. -D: Specify user home directory, default is/home/username

-M together with-B to remove the contents of the user's home directory

4. -S: Specifies the shell environment in which the user resides

5. -G: Specify additional groups for users

For example, modify the user maedu uid to 1000 home directory/oracle,shell for/bin/bash

#usermod –u 1000–d/oracle–s/bin/bash-m maedu

C Add user group: Groupadd [Options] GroupName

Options

1. -g:gid

For example, add the user group GRP uid to 1010 #groupadd –g 1010 GRP

D Delete User: Userdel [options]username

Options

1. -R: Delete together with home directory

For example, delete user maedu and home directory

#userdel –r maedu

8. How to get administrator privileges for Linux ordinary users

(1) Add a user, first with the AddUser command to add a normal user, the command is as follows:

                     #adduser Tommy </p> <p>//Add a user named student
                     #passwd Student//Change Password
                     changing password for User student.
                     new UNIX Password://Enter a new password here
                     Retype new UNIX Password://Enter password again
                     Passwd:all Authentication Tokens Updated successfully

(2) giving root privileges

A. Modify the/etc/sudoers file, find the following line, remove the previous comment (#)

# # allows people in group wheel to run all commands
%wheel all= (All) all

B. Then modify the user to belong to the root group (wheel) with the following command:
#usermod-G root Student

C. Modified, you can now log in with the Tommy account, and then use the command Su-, you can get root permissions to operate.

The above is my understanding of Linux users and their rights and collation, if there are improper welcome to correct!

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User and Rights Management for Linux