Usage: m4 [-?] [-Dvar[=value]] [filename(s)] Win32 implementation of the m4 preprocessor. -? Displays this usage string. -Dvar[=value] Defines an M4 preprocessor symbol with optional initial value. If no initial value is supplied, then the symbol is define with a null value. [filename(s)] Optional list of files to process. If no files are given, then preprocesses from stdin. The result is sent to stdout. See m4.man for language description. See m4.txt for implementation description.