win7和ubuntu12.04雙系統，修改啓動順序

剛安裝了雙系統，分別是windows7（先）和Ubuntu12.04（後）（非wubi安裝),. 默認是Linux啓動,經過下面的操做可把windows7改成默認啓動系統

啓動ubuntu後，在終端中輸入：

先備份 sudo cp /boot/grub/grub.cfg /boot/grub/grub.cfg.backup

修改啓動列表：sudo gedit /boot/grub/grub.cfg(注意不是sudo gedit /boot/grub/menu.lst,

貌似9.10就改成了grub.cfg）

而後找到
default 0
而後往下看，找你想默認啓動的操做系統！修改default 後面的數字，0對應第一個，1對應第二個，依次往下！如下是個人grub.cfg
默認是ubuntu！把0改成4就能夠了！(升級內核以後數字酌情修改）

#
# 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 (恢復模式)' --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    '載入 Linux ...'
linux    /boot/vmlinuz-2.6.32-21-generic root=UUID=0ee185d8-a603-4309-97b7-6440643becb7 ro single
echo    '載入引導虛擬磁盤 ...'
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_memtest86+ ###

### BEGIN /etc/grub.d/30_os-prober ###
menuentry "Windows 7 (loader) (on /dev/sda1)" {
insmod ntfs
set root='(hd0,1)'
search --no-floppy --fs-uuid --set 6e40b6ff40b6ccd9
chainloader +1
}
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# 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.
### END /etc/grub.d/40_custom ###

→→此處分割←←

上面的本身修改default後面的數字。！··

若是你以爲這樣不方便到話，我建議你把win7的那一項剪切到ubuntu前面

也就是這個樣子，這樣既美觀又方便（不用修改default後面的數字）。

#
# 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/30_os-prober ###
menuentry "Windows 7 (loader) (on /dev/sda1)" {
insmod ntfs
set root='(hd0,1)'
search --no-floppy --fs-uuid --set 6e40b6ff40b6ccd9
chainloader +1
}
### END /etc/grub.d/30_os-prober ###

### 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 (恢復模式)' --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    '載入 Linux ...'
linux    /boot/vmlinuz-2.6.32-21-generic root=UUID=0ee185d8-a603-4309-97b7-6440643becb7 ro single
echo    '載入引導虛擬磁盤 ...'
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_memtest86+ ###

### BEGIN /etc/grub.d/40_custom ###
# 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.
### END /etc/grub.d/40_custom ###

每次更新內核，你都要從新修改這個啓動項