I managed to change the group of user test to testgrp with this command
usermod -g test testgrp
Since there are various ways to manage users and groups I think no one can help you unless you show us the exact commands you are entering and the result you are seeing.
Thanks Dude .. I figured it out.
When user is created the group with the same name is also created and you can also assign other group to the user.
You can assign multiple groups to the user.
useradd -g testgrp -G test, test2,test3 oracle
Create user in OS:
usermod -g dba abc
1) You need to create the group first
check whether the group is created successfully
2) Then you
useradd -g dba -d /home/oracle username
check whether the user is created and assigned to that group
the issue is resolved .
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