更改Ubuntu 10.04和Windows 7启动顺序
转自:http://www.linuxidc.com/Linux/2010-10/29101.htm
刚安装了双系统，分别是windows7（先）和Ubuntu10.04（后）（非wubi安装),. 默认是Linux启动,通过下面的操作可把windows7改为默认启动系统
启动Ubuntu后，在终端中输入：

先备份 sudo cp /boot/grub/grub.cfg /boot/grub/grub.cfg.backup



修改启动列表：sudo gedit /boot/grub/grub.cfg(注意不是sudo gedit /boot/grub/menu.lst,

貌似9.10就改为了grub.cfg）

然后找到
default 0
然后往下看，找你想默认启动的操作系统！修改default 后面的数字，0对应第一个，1对应第二个，依次往下！以下是我的grub.cfg
默认是Ubuntu！把0改为4就可以了！(升级内核之后数字酌情修改）

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by /usr/sbin/grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
load_env
fi
set default="0"
if [ ${prev_saved_entry} ]; then
set saved_entry=${prev_saved_entry}
save_env saved_entry
set prev_saved_entry=
save_env prev_saved_entry
set boot_once=true
fi

function savedefault {
if [ -z ${boot_once} ]; then
saved_entry=${chosen}
save_env saved_entry
fi
}

function recordfail {
set recordfail=1
if [ -n ${have_grubenv} ]; then if [ -z ${boot_once} ]; then save_env recordfail; fi; fi
}
insmod ext2
set root='(hd0,3)'
search --no-floppy --fs-uuid --set 0ee185d8-a603-4309-97b7-6440643becb7
if loadfont /usr/share/grub/unicode.pf2 ; then
set gfxmode=640x480
insmod gfxterm
insmod vbe
if terminal_output gfxterm ; then true ; else
# For backward compatibility with versions of terminal.mod that don't
# understand terminal_output
terminal gfxterm
fi
fi
insmod ext2
set root='(hd0,3)'
search --no-floppy --fs-uuid --set 0ee185d8-a603-4309-97b7-6440643becb7
set locale_dir=($root)/boot/grub/locale
set lang=zh
insmod gettext
if [ ${recordfail} = 1 ]; then
set timeout=-1
else
set timeout=10
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/10_linux ###
menuentry 'Ubuntu，Linux 2.6.32-21-generic' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
insmod ext2
set root='(hd0,3)'
search --no-floppy --fs-uuid --set 0ee185d8-a603-4309-97b7-6440643becb7
linux    /boot/vmlinuz-2.6.32-21-generic root=UUID=0ee185d8-a603-4309-97b7-6440643becb7 ro   quiet splash
initrd    /boot/initrd.img-2.6.32-21-generic
}
menuentry 'Ubuntu，Linux 2.6.32-21-generic (恢复模式)' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
insmod ext2
set root='(hd0,3)'
search --no-floppy --fs-uuid --set 0ee185d8-a603-4309-97b7-6440643becb7
echo    '载入 Linux ...'
linux    /boot/vmlinuz-2.6.32-21-generic root=UUID=0ee185d8-a603-4309-97b7-6440643becb7 ro single
echo    '载入引导虚拟磁盘 ...'
initrd    /boot/initrd.img-2.6.32-21-generic
}
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_memtest86+ ###
menuentry "Memory test (memtest86+)" {
insmod ext2
set root='(hd0,3)'
search --no-floppy --fs-uuid --set 0ee185d8-a603-4309-97b7-6440643becb7
linux16    /boot/memtest86+.bin
}
menuentry "Memory test (memtest86+, serial console 115200)" {
insmod ext2
set root='(hd0,3)'
search --no-floppy --fs-uuid --set 0ee185d8-a603-4309-97b7-6440643becb7
linux16    /boot/memtest86+.bin console=ttyS0,115200n8
}
### END /etc/grub.d/20_