Windows NT4/3.5x:
111843 NTBackup Command Needs Both /L and /E for Exceptions Only Log
http://support.microsoft.com/?id=111843

The /E switch also lists the beginning and ending commands, plus a list of
the backed-up directories. It does not list any files unless there are
Exceptions. The /E switch is equivelent to a summary report in the GUI.

Server 2003:
814583 HOW TO: Use Command Line Parameters with the Ntbackup Command in
Windows
http://support.microsoft.com/?id=814583

Server/Professional 2000:
300439 How to use command line parameters with the "Ntbackup" command
http://support.microsoft.com/?id=300439

The comand line option for 2000 and 2003 products is:

Switch: /L:{f | s | n}
Description: Specifies the type of log file: f=full, s=summary, n=none (no
         log file is created).

Mark Wilson [MS]