EDIT mode to GENERAL mode: press ESC

general mode:

CLOSE FILE

:q!    ：force to close the file but not save

:wq! ：force to save and close the file

:q    : close the file but not save

:wq  : save and close the file

ENTER EDIT MODE

i ：insert a charactor before cursor, and enter EDIT mode

a : insert a charactor after cursor, and enter EDIT mode

o : insert a new line backward, and enter EDIT mode

MOVE CURSOR

) ：cursor move to the end of line

( ：cursor move to the beginning of line

G : cursor move to the last line of the file

DELETE

dd ：delete the line where cursor is

D : delete the charactors in the back of cursor in a line, include the character of cursor

x,X：in the character of a line, x means "delete the character of cursor", X means "delete the character before cursor

OTHERS

u ：cancel the last operation