更改 GRUB 实现默认启动 win7

一般的 /boot/grub/grub.cfg 文件内容如下：

   1:  #

   2:  # DO NOT EDIT THIS FILE

   3:  #

   4:  # It is automatically generated by /usr/sbin/grub-mkconfig using templates

   5:  # from /etc/grub.d and settings from /etc/default/grub

   6:  #

   7:   

   8:  ### BEGIN /etc/grub.d/00_header ###

   9:  if [ -s $prefix/grubenv ]; then

  10:    load_env

  11:  fi

  12:  set default="4"

  13:  if [ ${prev_saved_entry} ]; then

  14:    set saved_entry=${prev_saved_entry}

  15:    save_env saved_entry

  16:    set prev_saved_entry=

  17:    save_env prev_saved_entry

  18:    set boot_once=true

  19:  fi

  20:   

  21:  function savedefault {
  
  

  22:    if [ -z ${boot_once} ]; then

  23:      saved_entry=${chosen}

  24:      save_env saved_entry

  25:    fi

  26:  }

  27:   

  28:  function