NAME

group − group file, grp.h

DESCRIPTION

Group contains for each group the following information:

group name
encrypted password
numerical group ID
comma-separated list of all users allowed in the group

This is an ASCII file.  The fields are separated by colons; each group is separated from the next by a new-line.  If the password field is null, no password is associated with the group. 

There are two files of this form in the system, /etc/group and /etc/logingroup.  /etc/group exists to supply names for each group, and to support changing groups via newgrp(1).  /etc/logingroup provides a default group access list for each user via login(1) and initgroups(3C). 

The real and effective group ID set up by login for each user is defined in /etc/passwd (see passwd(4).  If /etc/logingroup is empty or non-existent, the default group access list is empty.  If /etc/logingroup and /etc/group are links to the same file, the default access list includes the entire set of groups associated with the user.  The group name and password fields in /etc/logingroup are never used; they are included only to give the two files a uniform format, allowing them to be linked together. 

All group ID’s used in /etc/logingroup or /etc/passwd should be defined in /etc/group.  No user should be associated with more than NGROUPS (see setgroups(2)) groups in /etc/logingroup. 

These files reside in directory /etc.  Because of the encrypted passwords, they can and do have general read permission and can be used, for example, to map numerical group ID’s to names. 

Grp.h describes the group structure returned by getgrent(3C), etc:

/* see getgrent(3C) */
structgroup {
char*gr_name;
char*gr_passwd;
intgr_gid;
char**gr_mem;
};

WARNINGS

The gid 9 is reserved for the Pascal Language operating system and the BASIC Language operating system.  These are operating systems for the Series 200 and Series 300 computers that can co-exist with HP-UX on the same disk.  Using this gid for other purposes can inhibit file transfer and sharing. 

FILES

/etc/group
/etc/logingroup

SEE ALSO

groups(1), newgrp(1), passwd(1), setgroups(2), crypt(3C), getgrent(3C), initgroups(3C), passwd(4). 

BUGS

There is no tool that helps you ensure that /etc/passwd, /etc/group, and /etc/logingroup are compatible. 

There is no tool that helps you set group passwords in /etc/group. 

Hewlett-Packard Company  —  Version B.1,  April 12, 1993