add user to a groups linux code example
Example 1: linux add user to group
# Change the primary group a user is assigned to, note the -g here.
# When you use a lowercase g, you assign a primary group. When you
# use an uppercase -G you assign a new secondary group.
usermod -g groupname username
Example 2: Adding users to groups
sudo usermod -a -G <groupname> <username>
e.g.
sudo usermod -a -G wonderland alice