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