group.5

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)group.5	8.3	4/9/91
.TH group 5 
.SH Name
group \- group file
.SH Description
.NXR "group file (general)"
The
.PN group
file is an ASCII file that contains the following information
for each group:
.PP
Group name
.br
Encrypted password
.br
Numerical group ID
.br
Comma-separated list of all users allowed in the group
.PP
Each group name is separated from the next by a new line.  
The fields are separated
by colons.
If the password field is null, no password is demanded.
.PP
Because of the encrypted
passwords, it can and does have general read
permission and can be used, for example,
to map numerical group IDs to names.
.PP
The 
.PN group
database can be distributed in a network by a naming service, 
such as Yellow Pages or BIND/Hesiod.  See the
\fIGuide to the Yellow Pages Service\fP
or the
\fIGuide to the BIND/Hesiod Service\fP
for setup information.
.SH Restrictions
The 
.MS passwd 1
command will not change the passwords.
.PP
Increasing the number of groups that a user is in beyond 8 can affect
services that use SUN RPC.  
The version of SUN RPC shipped with ULTRX V4.2 supports up to 32 groups.
Prior versions supported users being in up to 8 groups.  
Users who increase the
number of groups that they are a member of to more than 8 will not be
able to NFS mount file systems from ULTRIX servers older than V4.2.  
If
root group membership is increased to more than 8 groups on a V4.2 system,
the YP service may not work if that V4.2 system is in a mixed YP server
environment where there are both V4.2 and previous releases of YP servers.  
Again,
this incompatibility can only occur if a user's or root's group membership
is increased to more than 8 groups.
.SH Files
.PN /etc/group
.SH See Also
passwd(1), setgroups(2), crypt(3), getgrent(3), initgroups(3x), 
passwd(5)
.br
\fIGuide to the BIND/Hesiod Service\fP
.br
\fIGuide to the Yellow Pages Service\fP