linux users in group 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: check which users are part of a group linux

grep 'group-name-here' /etc/group

Example 3: how to check user in group linux

# to see the group joined by current user
$ id 

groups
groups {USERNAME}
groups vivek

Example 4: linux add user to group

# add user to additional group

usermod -G groupname username

Example 5: linux list user group

groups [user name]
# [user name] : (optionnal) the user to list the group of
#                           default is the one executing the command.