The letter 'd' is the delete operator in vi.  Because it is
	an operator, it has no effect by itself; but requires a 
	motion command to tell it the scope of the deletion.  As
	a special case, "dd" deletes the entire current line.

	So, what can we do with this delete operator?  Basically,
	'd' followed by any command that would move the cursor deletes
	text up to and including where the cursor would have gone for
	that motion.

	For example:

	  de	delete 'til end of word
	  d^	delete back to beginning of line
	  df:	delete until next occurence of a ':'	
	  dL	delete to bottom of screen
	  d/how	delete up to next occurrence of "how"

	  d?^[a-q]*:
		delete back to next line which matches "^[a-q]*:"


	Deletions are saved in queue of 10 buffers, numbered 1 thru 10.
	The most recent deletion is always in 1.  You can get back
	your most recent deletion with 'p', and other deletions
	with `"np' where " is itself, and n is the number of the buffer.

	Therefore, to reverse the order of 3 lines, you could use 
	this sequence of four commands:

		ddddp"2p