group(4)group(4)NAMEgroup - Group file
DESCRIPTION
The /etc/group database contains the following information for each
group: Group name Encrypted password Numerical group ID A comma-sepa‐
rated list of all users allowed in the group
Note
Do not put any spaces between a comma and a username; otherwise,
the username following the comma will not be made a part of the
desired group.
The /etc/group file is an ASCII file, with the fields separated by
colons. Each group is separated from the next by a new line. If the
password field is null, no password is demanded.
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.
Note that commands or scripts used for adding users to groups are sub‐
ject to the 225 character limit on line lengths. However, you can
split lines as appropriate.
RESTRICTIONS
Increasing the number of groups that a user is in beyond 16 can affect
services that use ONC RPC. Tru64 UNIX ONC RPC supports up to 32 groups
for compatibility with ULTRIX Version 4.2 and higher. Other vendors may
support only 16 groups. ULTRIX versions before 4.2 support up to 8
groups. Users who increase their group membership beyond 8 or 16
groups will not be able to NFS mount file systems from servers that
only support 8 or 16 groups over NFS. In addition, if root group mem‐
bership is increased beyond 8 or 16, the NIS service will not work in a
mixed NIS server environment where the servers support only 8 or 16
groups. The addgroup command limits the length of a group name to
eight characters or less.
FILES
/etc/group
SEE ALSO
Commands: addgroup(8), groupadd(8), adduser(8), groups(1), passwd(1)
Functions: setgroups(2)
Routines: initgroups(3)
Files: passwd(4)group(4)