186 Chapter 7 Adding New Users 7.3 T HE / ETC / GROUP FILE The /etc/group file contains the names of UNIX groups and a list of each group's members. Here's a portion of the group file from an AIX system: system:!:0:root,pconsole,esaadmin staff:!:1:ipsec,esaadmin,trent,ben,garth,evi bin:!:2:root,bin sys:!:3:root,bin,sys adm:!:4:bin,adm nobody:!:4294967294:nobody,lpd Each line represents one group and contains four fields: · · · · Group name Encrypted password or a placeholder GID number List of members, separated by commas (be careful not to add spaces) As in /etc/passwd, fields are separated by colons. Group names should be limited to eight characters for compatibility, although many systems do not actually re- quire this. It is possible to enter a group password to allow users not belonging to a group to enter it with the newgrp command, but this is rarely done. Only Linux has real support for group passwords. 8 A password can be set with the gpasswd