osx man page for checkgid

CHECKGID(8)						    BSD System Manager's Manual 					       CHECKGID(8)

NAME
     checkgid -- validate group identifiers

SYNOPSIS
     checkgid group ...

DESCRIPTION
     Given one or more group identifers on the command line (e.g., "httpd" or "#-1"), figure out whether they'll be valid for the server to use at
     run-time.

     If a groupname isn't found, or we can't setgid() to it, return -1.  If all groups are valid, return 0.

     This may need to be run as the superuser for the setgid() to succeed; running it as any other user may result in a false negative.

SEE ALSO
     httpd(8)

BSD
								 October 21, 2008							       BSD