Command Syntax:
gpasswd -d user_name group_name
Change user_name with your actual system user name and group_name with named of group from which you want to remove user.
Example
Use the following command to remove user jack from sysadmin group.
gpasswd -d jack sysadmin
Add User to Secondary Group
The following command will will add user jack to a secondary group named sysadmin.
usermod -aG sysadmin jack
Also run
#cat /etc/group | grep jack
This command will return all lines in the file containing user jack and
you can see all the groups jack is member of
Since you used the command gpasswd .how can we get confirmed about it??
you didnt mention any steps for that??????
You can verify the groups the user is a member of or the ones the user was removed from by running
# id
after running the
# gpasswd -d
command.