vim 最基本操作

insert mode:               i

save :                        :w

save and quit:           :wq

move cursor:             H (left)     J(next line)      K（last row）     L(right)

open a new line:       o  (below current line)     O(above current line)

delete:                       d

copy:                         y

paste:                        p

undo：                      u

line-connection:         J

find and replace:       :%s/f/r/g               f:  texts to find     r: texts to replace f  /g:optional,means global

open several files:    vim file1 file2 ...

switch opened files:  :n (to the next one)    :N(to the previous one)

insert a whole file to another:   :r  file2           open file1 and use the command to insert content in file2