GRPCK(1)                                                 GRPCK(1)

       grpck - verify integrity of group files

       grpck [-r] [group shadow]

       grpck  verifies the integrity of the system authentication
       information.   All   entries   in   the   /etc/group   and
       /etc/gshadow  are  checked  to  see that the entry has the
       proper format and valid data in each field.  The  user  is
       prompted  to  delete entries that are improperly formatted
       or which have other incorrectable errors.

       Checks are made to verify that each entry has

            - the correct number of fields
            - a unique group name
            - a valid list of members and administrators

       The checks for correct number of fields and  unique  group
       name  are  fatal.   If  the  entry has the wrong number of
       fields, the user will be prompted  to  delete  the  entire
       line.  If the user does not answer affirmatively, all fur-
       ther checks are bypassed.   An  entry  with  a  duplicated
       group  name  is  prompted  for deletion, but the remaining
       checks will still be made.  All other errors are  warnings
       and  the user is encouraged to run the groupmod command to
       correct the error.

       The commands which operate on the /etc/group file are  not
       able  to  alter  corrupted  or  duplicated entries.  grpck
       should be  used  in  those  circumstances  to  remove  the
       offending entry.

       By  default,  grpck  operates  on the files /etc/group and
       /etc/gshadow.  The user may select  alternate  files  with
       the  group  and shadow parameters.  Additionally, the user
       may execute the command in read-only  mode  by  specifying
       the  -r flag.  This causes all questions regarding changes
       to be answered no without user intervention.

       /etc/group - group account information
       /etc/gshadow - encrypted passwords and group administrator
       /etc/passwd - user information

       groupmod(8), group(5), passwd(5), shadow(5)

       The grpck command exits with the following values:

       0    Success

       1    Syntax Error

       2    One or more bad group entries

       3    Cannot open group files

       4    Cannot lock group files

       5    Cannot update group files

       Julianne Frances Haugh (