1group(4) File Formats group(4)
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6 group - group file
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9 The group file is a local source of group information. The group file
10 can be used in conjunction with other group sources, including the NIS
11 maps group.byname and group.bygid, the NIS+ table group, or group
12 information stored on an LDAP server. Programs use the getgrnam(3C)
13 routines to access this information.
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16 The group file contains a one-line entry for each group recognized by
17 the system, of the form:
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20 groupname:password: gid:user-list
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23 where
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25 groupname The name of the group. A string consisting of lower case
26 alphabetic characters and numeric characters. Neither a
27 colon (:) nor a NEWLINE can be part of a groupname. The
28 string must be less than MAXGLEN-1, usually 8, characters
29 long.
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32 gid The group's unique numerical ID (GID) within the system.
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35 user-list A comma-separated list of users allowed in the group.
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39 The maximum value of the gid field is 2147483647. To maximize interop‐
40 erability and compatibility, administrators are recommended to assign
41 groups using the range of GIDs below 60000 where possible.
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44 If the password field is empty, no password is demanded. During user
45 identification and authentication, the supplementary group access list
46 is initialized sequentially from information in this file. If a user is
47 in more groups than the system is configured for, {NGROUPS_MAX}, a
48 warning will be given and subsequent group specifications will be
49 ignored.
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52 Malformed entries cause routines that read this file to halt, in which
53 case group assignments specified further along are never made. To pre‐
54 vent this from happening, use grpck(1B) to check the /etc/group data‐
55 base from time to time.
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58 If the number of characters in an entry exceeds 2047, group maintenance
59 commands, such as groupdel(1M) and groupmod(1M), fail.
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62 Previous releases used a group entry beginning with a `+' (plus sign)
63 or `−' (minus sign) to selectively incorporate entries from a naming
64 service source (for example, an NIS map or data from an LDAP server)
65 for group. If still required, this is supported by specifying
66 group:compat in nsswitch.conf(4). The compat source may not be sup‐
67 ported in future releases. Possible sources are files followed by ldap
68 or nisplus. This has the effect of incorporating information from an
69 LDAP server or the entire contents of the NIS+ group table after the
70 group file.
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73 Example 1 Example group File.
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76 The following is an example of a group file:
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79 root::0:root
80 stooges:q.mJzTnu8icF.:10:larry,moe,curly
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85 and the sample group entry from nsswitch.conf:
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88 group: files ldap
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93 With these entries, the group stooges will have members larry, moe, and
94 curly, and all groups listed on the LDAP server are effectively incor‐
95 porated after the entry for stooges.
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99 If the group file was:
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102 root::0:root
103 stooges:q.mJzTnu8icF.:10:larry,moe,curly
104 +:
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109 and the group entry from nsswitch.conf:
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112 group: compat
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117 all the groups listed in the NIS group.bygid and group.byname maps
118 would be effectively incorporated after the entry for stooges.
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122 groups(1), grpck(1B), newgrp(1), groupadd(1M), groupdel(1M), group‐
123 mod(1M), getgrnam(3C), initgroups(3C), nsswitch.conf(4),
124 unistd.h(3HEAD)
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127 System Administration Guide: Basic Administration
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131SunOS 5.11 27 Aug 2008 group(4)