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
All systems normal

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