Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide

Command file syntax

To provide input to NMAKE with a command file, type

nmake @commandfile

In the commandfile field, enter the name of a file containing the same information as is normally entered on the command line.

NMAKE treats line breaks that occur between arguments as spaces. Macro definitions can span multiple lines if you end each line except the last with a backslash (\). Macro definitions that contain spaces must be enclosed by quotation marks, just as if they were entered directly on the command line.

Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide