ezcommand.pl script comes with a short README.txt and related PSTNCrossAuth.pm module. A E-mail Security Batch Reference Guide contains detailed documentation on how to use batch processing to manage Postini accounts (a .pdf version can be downloaded here). Basically this remote version of Postini’s ezcommand scripting environment lets you use the following command types: adduser, modifyuser, deleteuser, addalias, deletealias, suspenduser.
Now if you have an enterprise LDAP directory service that has been established as the “primary source of truth” for your IT systems, you may be able to avoid using ezcommand, at least on a regular basis. That’s because Postini also offers their free Directory Sync to let you synchronize changes on your directory with your org setup on Postini. Directory Sync looks like it is very flexible, allowing for especially granular configuration. For example, you can use exact, substring and regex matches on LDAP searches to include or exclude users. See the video training for more.