Lesson 8.1: Create, delete, and modify local user accounts

Important Files

User

User Entries : /etc/passwd
Format :
To add user : useradd <username>
To add password : passwd <password>
Files Containing default parameters while adding user : /etc/default/useradd
Another File Containing default parameters while adding user : /etc/login.defs

Creating Local User

Creating Users using Non default parameters

useradd [option] <username> Options

Comment : -c
Home Dir : -d
Expiry Date : -e
Primary Group : -g
Secondary Group : -G
UID : -u
Shell : -s

Example of creating a user with options

[root@sanjeeb ~]# useradd -c "John Doe, Kathmandu" -d /var/john -e 2024-10-30 -g staff -G admin,hr -s /bin/sh -u 1019 john 
 
[root@sanjeeb ~]# grep john /etc/passwd
john:x:1019:1003:John Doe, Kathmandu:/var/john:/bin/sh
 
[root@sanjeeb ~]# groups john 
john : staff admin hr
 
[root@sanjeeb ~]# chage -l john 
Last password change					: Sep 26, 2024
Password expires					: never
Password inactive					: never
Account expires						: Oct 30, 2024
Minimum number of days between password change		: 0
Maximum number of days between password change		: 99999
Number of days of warning before password expires	: 7
 
# To change the Minimum number of days between password change
# Maximum number of days between password change
# Number of days of warning before password expires
 
chage -m 1 -M 30 -W 3 <username>

Modifying Local User

Example of modifying a user with options

[root@sanjeeb ~]# usermod -c "John Doe, Nepal" john 
[root@sanjeeb ~]# grep john  /etc/passwd
john:x:1019:1003:John Doe, Nepal:/var/john:/bin/sh
 
[root@sanjeeb ~]# usermod -e 2024-12-30 john 
[root@sanjeeb ~]# chage -l john 
Last password change					: Sep 26, 2024
Password expires					: never
Password inactive					: never
Account expires						: Dec 30, 2024
Minimum number of days between password change		: 0
Maximum number of days between password change		: 99999
Number of days of warning before password expires	: 7

Deleting Local User

Deleting user without effecting it's files/dir

[root@sanjeeb /]# userdel hanuman 
[root@sanjeeb /]# ls /home/
bharat  boss  hanuman  laxman  ram  sanjeeb
[root@sanjeeb /]# ls /var/spool/mail/
bharat  boss  hanuman  laxman  ram  root  rpc  salesman1  sanjeeb
[root@sanjeeb /]#

Deleting user removing all related files/dir

[root@sanjeeb /]# userdel -r ram 
[root@sanjeeb /]# ls /home 
bharat  boss  hanuman  laxman  sanjeeb
[root@sanjeeb /]# ls /var/spool/mail 
bharat  boss  hanuman  laxman  root  rpc  salesman1  sanjeeb
[root@sanjeeb /]# grep ram /etc/group