vim 技巧: 將游標所在行移動到視窗上方, 下方或是中間

z.  -- 游標所在行移動到中央

zt  -- 游標所在行移動到上方

zb -- 游標所在行移動到下方

reference
https://nixtricks.wordpress.com/2009/08/30/vim-move-the-line-with-the-cursor-up-down-or-center-in-vim/https://nixtricks.wordpress.com/2009/08/30/vim-move-the-line-with-the-cursor-up-down-or-center-in-vim/