The program macros

macros is a simple macro processor that reads from standard input and writes to standard output. Macros may be defined in the input stream or on the command line. For example, if you call it with the command line

   $ macros -DMAC=123

   define(TEST,this is a test)
   define(a1,$1 is an argument)
   TEST
   a1(x)
   MAC

   this is a test
   x is an argument
   123