在终端里输入：sudo gedit /boot/grub/grub.cfg
先装windows而后装linux系统，默认启动项会非常多，执行上面的命令后，会打开一个文档，里面代码如下：
---------------------------------------------------------------------------------------------------------------( 这些小横线是我自己加的)
#
# 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="8"
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 ${boot_once} ]; then save_env recordfail; fi; fi
}
insmod ext2
set root='(hd0,9)'
search --no-floppy --fs-uuid --set fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f
if loadfont /usr/share/grub/unicode.pf2 ; then
set gfxmode=640x480
insmod gfxterm
insmod vbe
if terminal_output gfxterm ; then true ; else
# For backward compatibility with versions of terminal.mod that don't
# understand terminal_output
terminal gfxterm
fi
fi
insmod ext2
set root='(hd0,9)'
search --no-floppy --fs-uuid --set fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f
set locale_dir=($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, with Linux 2.6.32-31-generic' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
insmod ext2
set root='(hd0,9)'
search --no-floppy --fs-uuid --set fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f
linux /boot/vmlinuz-2.6.32-31-generic root=UUID=fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f ro quiet splash
initrd /boot/initrd.img-2.6.32-31-generic
}
menuentry 'Ubuntu, with Linux 2.6.32-31-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
insmod ext2
set root='(hd0,9)'
search --no-floppy --fs-uuid --set fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f
echo 'Loading Linux 2.6.32-31-generic ...'
linux /boot/vmlinuz-2.6.32-31-generic root=UUID=fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f ro single
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32-31-generic
}
menuentry 'Ubuntu, with Linux 2.6.32-30-generic' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
insmod ext2
set root='(hd0,9)'
search --no-floppy --fs-uuid --set fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f
linux /boot/vmlinuz-2.6.32-30-generic root=UUID=fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f ro quiet splash
initrd /boot/initrd.img-2.6.32-30-generic
}
menuentry 'Ubuntu, with Linux 2.6.32-30-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
insmod ext2
set root='(hd0,9)'
search --no-floppy --fs-uuid --set fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f
echo 'Loading Linux 2.6.32-30-generic ...'
linux /boot/vmlinuz-2.6.32-30-generic root=UUID=fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f ro single
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32-30-generic
}
menuentry 'Ubuntu, with Linux 2.6.32-24-generic' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
insmod ext2
set root='(hd0,9)'
search --no-floppy --fs-uuid --set fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f
linux /boot/vmlinuz-2.6.32-24-generic root=UUID=fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f ro quiet splash
initrd /boot/initrd.img-2.6.32-24-generic
}
menuentry 'Ubuntu, with Linux 2.6.32-24-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
insmod ext2
set root='(hd0,9)'
search --no-floppy --fs-uuid --set fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f
echo 'Loading Linux 2.6.32-24-generic ...'
linux /boot/vmlinuz-2.6.32-24-generic root=UUID=fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f ro single
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32-24-generic
}
### END /etc/grub.d/10_linux ###
### BEGIN /etc/grub.d/20_memtest86+ ###
menuentry "Memory test (memtest86+)" {
insmod ext2
set root='(hd0,9)'
search --no-floppy --fs-uuid --set fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f
linux16 /boot/memtest86+.bin
}
menuentry "Memory test (memtest86+, serial console 115200)" {
insmod ext2
set root='(hd0,9)'
search --no-floppy --fs-uuid --set fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f
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 de1ca47d1ca45277
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 ###
--------------------------------------------------------------------------------------------------------------------------------------
如上所示，每一个menuentry表示一个启动项，如：
menuentry "Windows 7 (loader) (on /dev/sda1)" {
insmod ntfs
set root='(hd0,1)'
search --no-floppy --fs-uuid --set de1ca47d1ca45277
chainloader +1
}
表示win7的启动项，处于最后一个（本人计算机共有9个启动项，一般的也可能是7个等等）。若想修改启动项，只需将红色标记的部分中的数字做个修改，如set default="8" 表示默认启动项是列表中的第九个，即本人计算机中的win7系统，“0”表示启动项列表中的第一个。蓝色标记的部分set timeout=10表示留10秒的时间供用户选择。当然了，如果嫌启动项太多太麻烦，只需将menuentry及其后面大括号所包含的部分删除，则相应的启动项就不会在启动时出现。
还可以采取另外一种办法：
将包含win7启动项的部分
### 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 de1ca47d1ca45277
chainloader +1
}
### END /etc/grub.d/30_os-prober ###
整个地放到一下部分的前面：
### BEGIN /etc/grub.d/10_linux ###
menuentry 'Ubuntu, with Linux 2.6.32-31-generic' --class ubuntu --class gnu-linux --class gnu --class os {
recordfail
insmod ext2
set root='(hd0,9)'
search --no-floppy --fs-uuid --set fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f
linux /boot/vmlinuz-2.6.32-31-generic root=UUID=fd9c0f6c-5c20-4d95-b3f4-eebca82bea0f ro quiet splash
initrd /boot/initrd.img-2.6.32-31-generic
}
。。。。。（在这里省略了）
### END /etc/grub.d/10_linux ###
（注：此时 set default="0" 不需要修改，因为此时win7已经排在第一个了，至于其他的很多启动项，反正在后面，不需要管它们。）
最后一种方法 ：
其实不用那么麻烦，要解决启动项问题，你只要新立得安装 startupmanager
“系统”——“系统管理”——“启动管理器” 即可进行设置
不仅可以选择默认启动项，还可以选择等待时间