Home IT Linux Windows Database Network Programming Server Mobile  
  Home \ Linux \ GRUB and Linux system repair     - Ubuntu 14.04 next upgrade to GNOME 3.12 (Linux)

- RHEL7 Apache MPM configuration (Server)

- Linux Study of --CentOS create local yum repository (Linux)

- KVM virtualization of nested virtualization (Linux)

- Linux iptables firewall settings whitelist (RHEL 6 and CentOS 7) (Linux)

- MariaDB 10 Multi-source replication (Database)

- ImageMagick Tutorial: How to cut images in Linux command line (Linux)

- How to monitor Linux system performance Nmon (Linux)

- Spring REST Exception Handling (Programming)

- Linux program analysis tool: ldd and nm (Linux)

- Summarize small problems encountered in the use Lua (Programming)

- Ubuntu and derivatives installation Atom 0.104.0 (Linux)

- Thinking in Java study notes - initialization and cleanup (Programming)

- How to Check notebook CPU temperature in Ubuntu (Linux)

- Linux system boot process ARM platforms (Linux)

- OpenWrt modify flash size (Linux)

- How to view the Linux QPS (Linux)

- Nodejs complete installation instructions for Express (Linux)

- Ubuntu 14.04 VirtualBox can not start solution (Linux)

- To install Redis under Linux (Database)

  GRUB and Linux system repair
  Add Date : 2017-09-03      
  GRUB configuration parsing
Configuration files are saved in a separate division /boot/grub/grub.conf[/boot partition should preferably come out]

Soft links saved in /etc/grub.conf

1, grub.conf file analysis

default # default start system

timeout # default wait time in seconds s

splashimage # define GRUB boot background image

 # (Hd0,0) # specify where the boot partition / -> the first hard disk, first partition

hiddenmenu # Hide menu

title CentOS (2.6.32-358.el6.i686) # menu item name, its contents can be modified

 root (hd0,0) # defines the GRUB kernel root device that is where the partition, the / boot directory, on behalf of all partitions on the boot device resides

 kernel /vmlinuz-2.6.32-358.el6.i686 ro root = UU ... # define the location of the kernel Note: / here does not mean that is the root partition, but rather that the / boot directory

 initrd /initramfs-2.6.32-358.el6.i686.img # load the image file, for more information, refer to < CentOS 6.X boot process> this blog

Single-user mode applications
Case: forget the root password, abnormal power failure

1. When the system starts, press the Esc key to enter the GRUB menu

GRUB function keys:

 e: Edit the current boot menu items // edit

 c: to enter the GRUB command line // command

 b: Start the current boot menu items //

 d: delete the current line // delete

 Esc: return to the GRUB boot menu interface, cancel any modifications made to the current single

2. Click the kernel line and press e to edit the start level, starting with the corresponding end of the line run level, such as: 1 or s, Enter, b to enter single-user mode

 passwd root # to change the root password

   # Can also be used for other settings, such as abnormal after power failure, the file system repair.

Setting GRUB password
Step 1: Set the ciphertext, the cipher text and copy

Method 1. Use the built-in GRUB grub-md5-crypt command

Method 2. Use md5crypt command in the GRUB interactive command-line interface

Step two: modify the configuration file /boot/grub/grub.conf

Added: password --md5 $ 1 $ EszU60 $ Mc2BwxeWUH / 8q3iqbRknz0 # - md5 representation is md5 encrypted

After the restart

OK, we're done!

GRUB repair
Case: When the boot into the grub menu interface but no, only a grub> prompt


grub> cat /grub/grub.conf # Found an error

Manual boot Linux system:

 grub> root (hd0,0)

 grub> kernel /vmlinuz-2.6.18-14 ro root = LABEL = / 3 # If you knock on the wrong this time, please pay attention to the message

 grub> initrd /initrd-2.6.18-14.img

 grub> boot # At this point you can use the Tab command completion

Linux ultimate recovery mode

Case: / etc / inittab file is damaged or missing, or other serious harm, cause the system to not start

Repair process

1. Place the installation disk into the drive, restart the system, F2 to enter the BIOS, the BIOS, the system is set to CD-ROM guide.

2.boot prompt, enter:

linux rescue

3. Enter into repair mode.

Follow the prompts to enter the system after:

4. Type chroot / mnt / sysimage # change the root partition

5, and then in front of the message, you can repair

6, the repair is completed, exit, reboot, done!


Linux no matter how serious the damage, you can enter the CD Linux repair repair environment, like important files are deleted, root with GRUB password forgot all about it, almost all errors; this time, although you are running Linux on the disc, but can the data on existing systems to be modified.
- Ubuntu 14.04 LTS next upgrade gcc to gcc-4.9, gcc-5 version (Linux)
- About enhanced Linux / Unix server system security program (Linux)
- CentOS7 installation configuration (Server)
- Download Google Android source code under Ubuntu 4.4 (Linux)
- Linux Creating a new user error Creating mailbox file: File exists (Linux)
- CentOS 7 server environment to quickly build Linux (Server)
- 10 Nginx safety tips (Linux)
- Xshell upload files to achieve Windows host Linux (Linux)
- RHEL5 establish a local yum source (Linux)
- How to upgrade to Oracle 11g Oracle 12c (Database)
- Locale files under Ubuntu (Linux)
- Top 10: HTML5, JavaScript 3D game engine and framework (Linux)
- Python 3.5 await / async (Programming)
- Oracle 11g contraction table space error ORA-03297: file contains used data beyondrequested RESIZE value (Database)
- Nagios (centreon) monitoring LVS (Server)
- Sort sql MySQL 5.6 upgrade slow Cause Analysis (Database)
- Debian (Wheezy) Install Java environment / replace OpenJDK as the SUN JDK (Linux)
- In-depth understanding of PHP ini configuration (Server)
- How to convert images, audio and video formats on Ubuntu (Linux)
- CoreCLR compiled in Linux CentOS (Linux)
  CopyRight 2002-2016 newfreesoft.com, All Rights Reserved.