So far, we've been creating user accounts within our system; what about group accounts? Well, here's the thing, when we create an account using the useradd command, we are also indirectly creating a group account using the same name as the user. To prove this, let's take a look at the /etc/login.def file:
root@ubuntu:/home/philip# cat /etc/login.defs | grep GRO
# TTYGROUP Login tty will be assigned this group ownership.
# which owns the terminals, define TTYGROUP to the group number and
# TTYPERM to 0620. Otherwise leave TTYGROUP commented out and assign
TTYGROUP tty
# If USERGROUPS_ENAB is set to "yes", that will modify this UMASK default value
USERGROUPS_ENAB yes
#CONSOLE_GROUPS floppy:audio:cdrom
root@ubuntu:/home/philip#
Based on the preceding output, the USERGROUPS_ENAB yes variable enables...