grub密码设置与修改
默认GRUB启动参数可以的进入单用户模式从而修改root密码,如果想要给GRUB菜单设置密码，可以修改/etc/grub.conf文件 （/boot/grub/grub.conf）
设置grub密码
密码生成
grub-md5-crypt 生成md5密码 grub-crypt 生成sha256密码
写入配置文件
vim /etc/grub.conf 1 # grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd0,)
# kernel /vmlinuz-version ro root=/dev/sda2
# initrd /initrd-[generic-]version.img
#boot=/dev/sda
default=
timeout=
splashimage=(hd0,)/grub/splash.xpm.gz
hiddenmenu
password=123456 #明文密码
#password --md5 $1$XEWYA/$5HUOCImxTf4UwpYQGMlue/ #密文密码 md5密码123456
#password --sha-256 $5$hwX.zwZ7EMcJW0Tu$GaZZGQzvAAPfSUpK5mW.Jq3v4hZ/1IludjcWmjwPMT3 #密文密码sha密码123456
title CentOS (2.6.-642.13..el6.i686.debug)
root (hd0,)
kernel /vmlinuz-2.6.-642.13..el6.i686.debug ro root=UUID=a298ed8b-f1b6-409b-a17c-59e72d rd_NO_LUKS KEYBOARDTYPE=pc
KEYTABLE=us rd_NO_MD crashkernel=auto LANG=zh_CN.UTF- rd_NO_LV M rd_NO_DM
initrd /initramfs-2.6.-642.13..el6.i686.debug.img
title CentOS (2.6.-642.13..el6.i686)
root (hd0,)
kernel /vmlinuz-2.6.-642.13..el6.i686 ro root=UUID=a298ed8b-f1b6-409b-a17c-59e72d401964 rd_NO_LUKS
KEYBOARDTYPE=pc KEYTABLE=us rd_NO_MD crashkernel=auto LANG=zh_CN.UTF- rd_NO_LVM rd_N O_DM
initrd /initramfs-2.6.-642.13..el6.i686.img
title CentOS (2.6.-.el6.i686)
root (hd0,)
重启系统进入grub,输入p,会提示输入密码
grub密码清除
1.在bios中进行光驱引导.
2.开机选择Bescure installed system.
3.选择语言.
4.根据自己的需要配置网卡.
5.系统会自动查找磁盘中的Linux分区并尝试将其挂载到/mnt/sysimage目录,选continue..
6.当出现这个提示的时候应该记住，他提示的命令：chroot /mnt/sysimage.
7.选择shell.
8.紧接着下面会出现shell,并在端口中输入chroot /mnt/sysimage.
9.执行vi /etc/grup.conf,删除配置文件中的密码.
10.保存退出,关机重启,不要忘记修改bios.