grpck(8) - f14

1GRPCK(8)                  System Management Commands                  GRPCK(8)
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NAME

6       grpck - verify integrity of group files
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SYNOPSIS

9       grpck [-r] [group [ shadow ]]
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11       grpck [-s] [group [ shadow ]]
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DESCRIPTION

14       The grpck command verifies the integrity of the groups information. It
15       checks that all entries in /etc/group and /etc/gshadow have the proper
16       format and contain valid data. The user is prompted to delete entries
17       that are improperly formatted or which have other uncorrectable errors.
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19       Checks are made to verify that each entry has:
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21       ·   the correct number of fields
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23       ·   a unique and valid group name
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25       ·   a valid group identifier (/etc/group only)
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27       ·   a valid list of members and administrators
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29       ·   a corresponding entry in the /etc/gshadow file (respectively
30           /etc/group for the gshadow checks)
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32       The checks for correct number of fields and unique group name are
33       fatal. If an entry has the wrong number of fields, the user will be
34       prompted to delete the entire line. If the user does not answer
35       affirmatively, all further checks are bypassed. An entry with a
36       duplicated group name is prompted for deletion, but the remaining
37       checks will still be made. All other errors are warnings and the user
38       is encouraged to run the groupmod command to correct the error.
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40       The commands which operate on the /etc/group and /etc/gshadow files are
41       not able to alter corrupted or duplicated entries.  grpck should be
42       used in those circumstances to remove the offending entries.
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OPTIONS

45       The options which apply to the grpck command are:
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47       -r
48           Execute the grpck command in read-only mode. This causes all
49           questions regarding changes to be answered no without user
50           intervention.
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52       -s
53           Sort entries in /etc/group and /etc/gshadow by GID.
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55       By default, grpck operates on /etc/groupand /etc/gshadow. The user may
56       select alternate files with the group and shadow parameters.
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CONFIGURATION

59       The following configuration variables in /etc/login.defs change the
60       behavior of this tool:
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62       MAX_MEMBERS_PER_GROUP (number)
63           Maximum members per group entry. When the maximum is reached, a new
64           group entry (line) is started in /etc/group (with the same name,
65           same password, and same GID).
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67           The default value is 0, meaning that there are no limits in the
68           number of members in a group.
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70           This feature (split group) permits to limit the length of lines in
71           the group file. This is useful to make sure that lines for NIS
72           groups are not larger than 1024 characters.
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74           If you need to enforce such limit, you can use 25.
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76           Note: split groups may not be supported by all tools (even in the
77           Shadow toolsuite). You should not use this variable unless you
78           really need it.
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FILES

81       /etc/group
82           Group account information.
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84       /etc/gshadow
85           Secure group account information.
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87       /etc/passwd
88           User account information.
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EXIT VALUES

91       The grpck command exits with the following values:
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93       0
94           success
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96       1
97           invalid command syntax
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99       2
100           one or more bad group entries
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102       3
103           can´t open group files
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105       4
106           can´t lock group files
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108       5
109           can´t update group files
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