vi (visual editor) help message:
      is in 3 states: insert, command, line(ex)
 insert-- i I insert, a A append, o O open line below/above,  ends insert
 command-- x X del-char, dw del-word, dd del-line, p put after, P put before
   yw yank word to yank buffer, Y yank line, INTEGER may precede many of these
   cw change word, C change line right of here,  ends changes, ZZ exits
   saving changes.
 command moves-- h ( left ), j  ( down ), k - ( up ), l ( right ),
   w e b ( move word, word end, back ), 1G nmbrG G ( line go, end ), 0 \$ 
   ( move Beg/End of line ) .. number(s) allowed before most commands
 line-- Prefixed with <:> key and terminated with  key ( takes ed editor
   commands in lower left corner of crt .. man ed .. ) include:
   /string ?string ( search down or up for string ), q quit, q! lose changes,
   w wq ( like ZZ, write or write and quit )
   range cmd .. .,\$s/old/new/g from current line to eof subst old for new for
     each occurence on each line
   !command will execute a Unix shell command from within vi
   r !command will read into current session the results of a NONINTERACTIVE
     shell command.