让 Vim 记住上次光标所在的行

" Only do this part when compiled with support for autocommands
if has("autocmd")
   " In text files, always limit the width of text to 78 characters
   autocmd BufRead *.txt set tw=78
   " When editing a file, always jump to the last cursor position
   autocmd BufReadPost *
     \ if line("'\"") > 0 && line ("'\"") <= line("$") |
     \   exe "normal! g'\"" |
     \ endif
endif