Users and Group

Users and Group Management

User – These are login accounts through which we can access the features of an operating system

Group – It is a place where users are placed to implement security, permissions and policies.

There are two type of users available in Linux

    1) Root – It is the administrator account

    2) Normal or Standard user – They are like restricted user standard user \

If you logged through root “#” will appeared

If you are logged through normal user “$” will appeared

There are total 69535 users can exist in a Linux server

There are total 65535 groups we can create in a Linux server  

Point – In Linux background server is known as demon services  

Note – In Centos7 there are 0 to 999 users by default you will get

Files Regarding Users & Groups

/etc/passwd – This five contains all the information regarding users

 /etc/shadow – This file contains encrypted form of password

/etc/group – This file contains file regarding group details

COMMANDS IN USER AND GROUP MANAGEMENT

S.no	Command	Work
1	useradd <new name>	To add a new user
2	groupadd<new name>	To add a new group
3	passwd <user name>	To set password to existing user
4	useradd –g <primary group> -G<secondary group> <user name>	To create a new user with primary & secondary existing group
5	usermod –g <primary group> -G<secondary group> <exiting user>	To add existing user in existing groups
6	usermod –l <user name >	Rename the existing user
7	userdel <user name >	To delete existing user
8	userdel –r < user name >	Delete existing user with all files
9	usermod –C <comment > <user name >	To implement comment name in user name
10	usermod –s /sbin/nologin <user name >	To make user no login
11	usermod –s /bin/bash <user name >	To make user enable
12	su  - <user name >	To Login with user
13	logout or exit	To exit from logged in user