grpck - verify integrity of group files
[options] [ group [ shadow ]]
command verifies the integrity of the groups information. It
checks that all entries in /etc/group and /etc/gshadow have the proper format
and contain valid data. The user is prompted to delete entries that are
improperly formatted or which have other uncorrectable errors.
Checks are made to verify that each entry has:
•the correct number of fields
•a unique and valid group name
•a valid group identifier (/etc/group
•a valid list of members and
•a corresponding entry in the
/etc/gshadow file (respectively /etc/group for the gshadow checks)
The checks for correct number of fields and unique group name are fatal. If an
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 further 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 and /etc/gshadow files are not able
to alter corrupted or duplicated entries. grpck
should be used in those
circumstances to remove the offending entries.
options cannot be combined.
The options which apply to the grpck
Display help message and exit.
Execute the grpck command in read-only
mode. This causes all questions regarding changes to be answered no
without user intervention.
, --root CHROOT_DIR
Apply changes in the CHROOT_DIR
directory and use the configuration files from the CHROOT_DIR
Sort entries in /etc/group and /etc/gshadow by
By default, grpck
operates on /etc/group and /etc/gshadow. The user may
select alternate files with the group
The following configuration variables in /etc/login.defs change the behavior of
Maximum members per group entry. When the
maximum is reached, a new group entry (line) is started in /etc/group (with
the same name, same password, and same GID).
The default value is 0, meaning that there are no limits in the number of
members in a group.
This feature (split group) permits to limit the length of lines in the group
file. This is useful to make sure that lines for NIS groups are not larger
than 1024 characters.
If you need to enforce such limit, you can use 25.
Note: split groups may not be supported by all tools (even in the Shadow
toolsuite). You should not use this variable unless you really need it.
Group account information.
Secure group account information.
User account information.
command exits with the following values:
invalid command syntax
one or more bad group entries
can't open group files
can't lock group files
can't update group files