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_c