Centos7 + Windows7 双系统

以前装双系统只要先装Windows7，然后再装Centos7的话，grub会自动添加原有的Windows7系统。不过在新的Centos7中需要手动修改、

步骤如下

$ sudo vi /etc/grub.d/40_custom

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry 'Windows7'{
set root=(hd0,1)
chainloader +1
}

$ grub2-mkconfig -o /boot/grub2/grub.cfg
$ reboot