vim开启了文件类型检测，即”filetype on”，并且关闭了vi兼容，”set nocompatible”。按照文档上说法：
Detail: The “:filetype on” command will load one of these files:
Mac $VIMRUNTIME:filetype.vim
Unix $VIMRUNTIME/filetype.vim
This file is a Vim script that defines autocommands for the
BufNewFile and BufRead events. If the file type is not found by the
name, the file $VIMRUNTIME/scripts.vim is used to detect it from the
contents of the file.
其中filetype.vim里关于markdown有下面条目：
” Markdown
au BufNewFile,BufRead *.markdown,*.mdown,*.mkd,*.mkdn,README.md setf markdown
说明README.md将被视为markdown文件。
可是我打开markdown文件后，却显示为vimwiki文件(vimwiki为我安装的插件)，如下图：
这个是什么原因呢？
The easiest solution to this is to change the default setting of the g:vimwiki_ext2syntax variable in your .vimrc (or Janus could make this the default) as follows:
let g:vimwiki_ext2syntax = {}
The default value of g:vimwikiext2syntax = {‘.md’: ‘markdown’}. This setting tells vimwiki to recognize files with a “.md” extension, overriding previous filetype associations. See “:help vimwikiext2syntax”.
谢邀 … 我打开 README.md 得到的是正确的结果 … 所以猜测是 vimwiki 覆盖了 vim 的默认配置 …
在 g:vimwiki_list 里面去掉 .md 文件试试看 ..?