先运行update-grub命令生成一次grub配置,顺便查看一下识别出来的引导菜单内容

[email protected]:~# update-grub
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.4.0-21-generic
Found initrd image: /boot/initrd.img-4.4.0-21-generic
Found memtest86+ image: /boot/memtest86+.elf
Found memtest86+ image: /boot/memtest86+.bin
Found Windows 7 (loader) on /dev/sda1
done
[email protected]:~# 

注意看,以上共有5个菜单项,最后一个是windows7

接下来我们来看看gurb配置文件/etc/default/grub

[email protected]:~# cat /etc/default/grub 
# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
#   info -f grub -n 'Simple configuration'

GRUB_DEFAULT=4
#GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=3
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX="locale=zh_CN"

# Uncomment to enable BadRAM filtering, modify to suit your needs
# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"

# Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL=console

# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=640x480

# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
#GRUB_DISABLE_LINUX_UUID=true

# Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_RECOVERY="true"

# Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"

其中GRUB_DEFAULT就是默认引导项,这里设置为4,对应的为windows7,说明一下,这个引导序列号是从0开始排的,所以第五项window7的序列号应为为4

GRUB_TIMEOUT表示菜单等待时间,单位为秒(s)

还值得说明的是GRUB_GFXMODE,设置grub显示的分辨率

自定义编辑完grub配置文件后,运行update-grub使配置生效即可。