git config --global core.whitespace cr-at-eol
cr-at-eol treats a carriage-return at the end of line as part of the line terminator, i.e. with it, trailing-space does not
trigger if the character before such a carriage-return is not a whitespace (not enabled by default).
去掉git提交时出现很多^M提示符，
git config --global core.filemode false
git 提交时忽略文件权限，该值默认是true
