vi commands

Switch to command mode <ESC>

ESC	start command mode ( it starts in command mode )
i	change to insert mode
:q	quit
:wq	write and quit
:w	write the file
:#	goto line #
/str	search down for "str"
?str	search up for "str"
dd	delete line
x	delete character
dw	delete word ( cut )
yy	yank line ( copy )
yw	yank word
p	paste
u	undo ( only limit is the last write )
.	repeat last change
cw	change word

Go to line number ## :##

Undo previous command: u

Undo all changes to line: U

Search backward for string: ?string

Search forward for string: /string

% (entire file) s (search and replace) /old text with new/ c (confirm) g (global - all): %s/oldstring/newstring/cg

Delete 5 lines (to buffer): 5dd

Delete lines 5-10:5,10d

string replacement

Sometimes you want to replace one string with another. This is done with the ex command "s". The form of the replacement is :

: line_range s/old/new/g

ex ( replace foo with bar from line 10 to 20 ) :

:10,20s/foo/bar/g

You can use visual mode to select the lines, when you type the colon to start the command it will use symbols for the visual line range.