安装步骤：

1.sudo pip install pyflakes (必要时加个代理更快 -i http://e.pypi.python.org/simple)  先安装pip

2.去https://github.com/kevinw/pyflakes-vim下载pyflakes-vim插件

3.解压

4.sudo vi /etc/vim/vimrc,添加“

filetype on            " enables filetype detection
filetype plugin on     " enables filetype specific plugins