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group(4) [osf1 man page]

group(4)						     Kernel Interfaces Manual							  group(4)

group - 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 subject 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 membership 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
Commands: addgroup(8), groupadd(8), adduser(8), groups(1), passwd(1) Functions: setgroups(2) Routines: initgroups(3) Files: passwd(4) delim off group(4)

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group(4)						     Kernel Interfaces Manual							  group(4)

group, logingroup - group file, grp.h DESCRIPTION
contains for each group the following information: o group name o encrypted password o numerical group ID o comma-separated list of all users allowed in the group The file is an ASCII file. Fields are separated by colons, and each group is separated from the next by a new-line. No spaces should sep- arate the fields or parts of fields on any line. If the password field is null, no password is associated with the group. There are two files of this form in the system, and The file exists to supply names for each group, and to support changing groups by means of the utility (see newgrp(1)). provides a default group access list for each user via and (see login(1) and initgroups(3C)). The real and effective group ID set up by for each user is defined in (see passwd(4)). If is empty, the default group access list is empty. If and 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 are never used; they are included only to give the two files a uniform format, allowing them to be linked together. All group IDs used in or should be defined in These files reside in directory Because of the encrypted passwords, these files can and do have general read permission and can be used, for example, to map numerical group IDs to names. The group structure is defined in and includes the following members: NETWORKING FEATURES
NIS The file can contain a line beginning with a plus which means to incorporate entries from Network Information Services (NIS). There are two styles of entries: means to insert the entire contents of NIS group file at that point, and means to insert the entry (if any) for name from NIS at that point. If a entry has a non-null password or group member field, the contents of that field overide what is contained in NIS. The numerical group ID field cannot be overridden. A group file can also have a line beginning with a minus these entries are used to disallow group entries. There is only one style of entry; an entry that consists of means to disallow any subsequent entry (if any) for name. These entries are disallowed regardless of whether the subsequent entry comes from the NIS or the local group file. WARNINGS
Group files must not contain any blank lines. Blank lines can cause unpredictable behavior in system administration software that uses these files. Group ID (gid) 9 is reserved for the Pascal Language operating system and the BASIC Language operating system. These are operating systems for Series 300/400 computers that can co-exist with HP-UX on the same disk. Using this gid for other purposes can inhibit file transfer and sharing. The length of each line in is limited to as defined in Because of this limit, users should not be listed in their primary group - only in their additional groups. If is linked to group membership for a user is managed by NIS, and no NIS server is able to respond, that user cannot log in until a server does respond. There is no single tool available to completely ensure that and are compatible. However, and can be used to simplify the task (see pwck(1M)). There is no tool for setting group passwords in DEPENDENCIES
NIS Here is a sample file: Group has a gid of 1 and members and The group is ignored since it appears after the entry Also, the group has members and and the password and group ID of the NIS entry for the group All groups listed in the NIS are pulled in and placed after the entry for The plus and minus features are part of NIS. Therefore if NIS is not installed, these features cannot work. FILES
groups(1), newgrp(1), passwd(1), setgroups(2), crypt(3C), getgrent(3C), initgroups(3C), passwd(4). STANDARDS CONFORMANCE
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