root# /usr/sbin/DirectoryService -h
Usage: /usr/sbin/DirectoryService [-hv]
-h Display this list of options.
-v Display the release version.

The command:
killall -HUP DirectoryService

Related

• http://lists.apple.com/archives/macos-x-server/2007/Nov/msg00849.html
• http://lists.apple.com/archives/macos-x-server/2007/Nov/msg00843.html
• http://developer.apple.com/releasenotes/MacOSXServer/RN-DirectoryServicesSession549/index.html