linux默认启动命令行_win10和linux双系统切换[通俗易懂]

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=640×480

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。)