r.water.drain

[Morris Trimmer]

Users, 
  I must be missing something conceptually or software wise .  .  .  
  I am trying to find the drainage basin above a point in a stream.  I can not 
get r.watershed to do this and it does not seem to be intended to.  Though 
r.water.drain is in my on-line manual and looks like it is exactly what I need, 
the program itself is not in my grass version 4.1.  Should it be?  Is it a 
contributed program that I need to compile?  Or, is there another way to go 
about this.  Thanks !  !  !
     Morris