Hi!
On going thrugh the man page of omscan, you would come to know that omscan.server runs continously, the details is as below:
Excerpts from man page for omscan:
The server omscan.server operates as a Scalix service (Omscan Service) which can
be started/stopped using omon/omoff as required. It also supports various standard
features available to a service such as setting nice value and running auxiliary
processes. Once (re)started, the server will continue from the last processing point,
systematically scanning the message store for inconsistencies and storing the results
so that the tool omscan can be used in passive mode. For details of program options
available to the server, see its configuration file at ~/sys/omscan.cfg.
If you would have run omscan.server --help, you come to know that -F option expects the configuration file for omscan.server.
Warm Regards,
Subir