cash_COW.csh
  Set a shell variable 'cash',
  and an environment variable 'COW'.
 
  Before running this script, you should
  set these variables yourself, 
    set cash = 10
    setenv COW 100
  and then, after running the script,
  check the current values of the variables again.
 
  Before: cash = NOT DEFINED.
  After:  cash = 30.
 
  Before: COW = 2.
  After:  COW = 50.
 
  Now you should check the value of these variables
  by typing
    DOLLAR(cash)
  and
    DOLLAR(COW).