This file is named /etc/group and is similar to the password and shadow files; in other words, it is an ASCII file consisting of colon-separated strings. It contains definitions for all the groups that are used on the system and, by default, looks like the one shown here:
hydrogen# cat /etc/group root::0:root other::1: bin::2:root,bin,daemon sys::3:root,bin,sys,adm adm::4:root,adm,daemon uucp::5:root,uucp mail::6:root tty::7:root,tty,adm lp::8:root,lp,adm nuucp::9:root,nuucp staff::10: daemon::12:root,daemon sysadmin::14: nobody::60001: noaccess::60002: nogroup::65534: hydrogen#
The field entries are as follows.
This is the actual group name.
This field is largely historical and now rarely ...