chkgrp - check the syntax of the group file
Synopsis Description Files Exit Status Diagnostics See Also History Authors Bugs
The chkgrp utility scans the given file or, failing that, the system-wide group file for errors. Specifically, it checks that every non-blank, non-comment entry is composed of four colon-separated fields, that none of them contains whitespace, and that the third field (the group ID) is numeric. It will also check for invalid characters in the group names and group members.