code: def show(*args, **kw):
      
  
      if len(kw):
          raise TypeError('unexpected keyword argument: %r' % list(kw))
  
      if args:
          for arg in args:
              print(envget(arg))
      else:
          # print them all
          listVars(prefix="    ", equals="=")
docs: Print value of IRAF or OS environment variables.