format of the group permissions file
Lines whose first non-whitespace character is a pound-sign (#) are comments, and are ignored. Blank lines that consist only of spaces, tabs or newlines are also ignored.
The group field is the group name used for
granting file access to users who are members of the group. The
gid field is the number associated with the group
name. They should both be unique across the system (and often across a group
of systems) since they control file access. The passwd
field is an optional encrypted password. This field is
rarely used and an asterisk is normally placed in it rather than leaving it
blank. The member field contains the names of users
granted the privileges of group. The member names are
separated by commas without spaces or newlines. A user is automatically in a
group if that group was specified in their
/etc/passwd entry and does not need to be added to
that group in the
In older implementations, a group cannot have more than 200 members. The maximum line length of /etc/group is 1024 characters. Longer lines will be skipped. This limitation disappeared in FreeBSD 3.0. Older binaries that are statically linked, depend on old shared libraries, or non-FreeBSD binaries in compatibility mode may still have this limit.