Useful Commands

terminal (mac)

!!     ... rewrite, appending new commands onto previous command.
ctrl a ... move to beginning of line
ctrl e ... move to end of line.

vim

esc    ... escape mode.
note: commands follow action number noun format.
d5d    ... delete 5 lines
d5w    ... delete 5 words
p      ... paste what was deleted  -- this is a different paste from command c and command v which is convenient.
u      ... each u is an undo
j      ... josh plicque likes this one.. ive still got to figure it out.
   shift i ... enter insert mode from escape mode at beginning of line.
   shift a ... enter insert mode from escape mode at end of line.
   i       ... enter insert mode from escape mode at current position of cursor.
:wq    ... write and quit from escape mode.
:q!    ... quit and overide changes.
:wq!   ... write and quit with overide.
:5     ... jump to line #5


:%s/foo/bar/g
Find each occurrence of 'foo' (in all lines), and replace it with 'bar'.

I go to this command often...
http://vim.wikia.com/wiki/Search_and_replace
this looked useful
http://www.radford.edu/~mhtay/CPSC120/VIM_Editor_Commands.htm

(pending double checking all commands)
visual mode
   from escape mode type v

scroll a number of lines
x   -- delete and enter insert mode can be put back in excape mode with p or undo
shift i -- insert mode at beginning ... type info. then, escape will put to beginning of all lines selected in visual mode.
shift a -- insert mode at the end   ... type info. then, escape will put to end of all lines selected in visual mode.