Unfortunately, Radiance input files are designed to be read with scanf(), which doesn't differentiate between spaces, tabs, and newlines. That means that the formatting of primitives in Radiance is almost entirely by convention. The only exceptions to this are for inline commands and comments, which must appear on a single line. (In the case of inline commands, the newline may be escaped with '\'.)
This is all spelled out pretty clearly in the basic reference manual:
You should probably consult it.