9.4.3.3.3.6 gg.handler.name.format.nullColumnChar
Specifies a special column prefix for a column value that exists in the trail and is set to NULL
.
The character used to represent the state of the column can be customized. For example:
gg.handler.handler1.format.nullColumnChar=N
By default, the null column value is set to an empty string and does not show.
Parent topic: Properties for CSV and Fixed Format Output