(this is taken from the very end of the Beginner's Guide to VI handout)
-----------------------------------------------------------------------
              
                           VI -- QUICK AND DIRTY
  		  	   ---------------------

Starting vi 				  Whatever you type in INSERT MODE
      vi				  is entered into your file.  COMMAND
Starting vi with a file			  MODE is used for moving around,
      vi filename			  deleting, saving, quitting, etc.

Insert (go to INSERT MODE)                In INSERT MODE
      i -- insert before cursor			DEL -- erase previous character
      a -- insert after cursor (append)		CTRL-U -- erase to start of
      o -- open a new line below			  insert or line
      O -- open a new line above		ESC -- go to COMMAND MODE

               All commands below are performed in COMMAND MODE

Deleting				  Saving and quitting
      x -- erase character at cursor		:w -- save (write) file
      dd -- delete line                         :q! -- quit without saving
      ndd -- delete n lines (eg, 10dd)		:wq -- save and quit
      dw -- delete word                         ZZ -- same as :wq

Moving around				  Undo
      h or left-arrow -- move left		u -- undo last command
      l or right-arrow -- move right
      j or down-arrow -- move down	  Miscellaneous
      k or up-arrow -- move up			J -- join this line with next
      $ -- go to end of line			% -- find matching ( ) { }
      ^ -- go to beginning of line		CTRL-L -- redraw messy screen
      w -- move forward one word                /xyz -- find word "xyz"
      CTRL-F -- forward one page
      CTRL-B -- back one page		  Useful options
      nG -- go to line n (eg, 10G)		:set ai -- autoindent
      G -- go to last line			:set nu -- show line numbers