GRPCK(8) 系统管理命令 GRPCK(8)

grpck - 检查组文件的完整性

grpck [选项] [group [ shadow ]]

The grpck 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.


•a valid group identifier (/etc/group only)
•a valid list of members and administrators
•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.

The -r and -s options cannot be combined.

The options which apply to the grpck command are:

-h, --help


-r, --read-only

Execute the grpck command in read-only mode. This causes all questions regarding changes to be answered no without user intervention.

-R, --root CHROOT_DIR

Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory.

-s, --sort

Sort entries in /etc/group and /etc/gshadow by GID.

By default, grpck operates on /etc/group and /etc/gshadow. The user may select alternate files with the group and shadow parameters.

The following configuration variables in /etc/login.defs change the behavior of this tool:


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).

默认值是 0,意味着组中的成员数没有限制。

此功能(分割组)允许限制组文件中的行长度。这对于确保 NIS 组的行比长于 1024 字符。

如果要强制这个限制,可以使用 25。

注意:分割组可能不受所有工具的支持(甚至在 Shadow 工具集中)。您不应该使用这个变量,除非真的需要。






The grpck 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

group(5), groupmod(8), gshadow(5), passwd(5), pwck(8), shadow(5).
2020-01-23 shadow-utils 4.8.1