grpck [option] [files]

System administration command. Remove corrupt or duplicate entries in the /etc/group and /etc/gshadow files. Generate warnings for other errors found. grpck will prompt for a "yes" or "no" before deleting entries. If the user replies "no," the program will exit. If run in a read-only mode, the reply to all prompts is "no." Alternate group and gshadow files can be checked. If other errors are found, the user will be encouraged to run the groupmod command.