用 SuSE Linux Rescue Mode 恢复超级用户口令

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用 SuSE Linux Rescue Mode 恢复超级用户口令

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SUSE LINUX contains a rescue system for accessing your Linux partitions from

the outside in the event of an emergency. The rescue system can be loaded

from CD, the network, or the SUSE FTP server. The rescue system includes

several help programs with which you can remedy large problems with

inaccessible hard disks, misconfigured configuration files, or other similar

problems.

Another component of the rescue system is Parted,

which is used for resizing partitions. This program can be launched

from within the rescue system, if you do not want to use

the resizer integrated in YaST. Information about

.

Boot your system as you would for installation. Select ‘Rescue

System

’

from the boot menu. The rescue system is then

decompressed, loaded onto a RAM disk as a new root file system, mounted, and

started.

Under Alt

-F1

to

Alt

-F3

, the rescue

system provides three virtual consoles.

You can log in as <code>root</code>

without a password. Press Alt

-F10

to enter the system console displaying the kernel and

syslog messages.

A shell and many other useful utilities, such as the

mount program, can be found in the

<code>/bin</code>

directory. The <code>sbin</code>

directory contains important file and network utilities for

reviewing and repairing the file system, including

reiserfsck and

e2fsck.

This directory also contains the most important binaries for system

maintenance, such as fdisk, mkfs, mkswap, mount, mount,

init, and shutdown, and ifconfig,

route, and netstat for

maintaining the network.

The directory <code>/usr/bin</code>

contains the

vi editor, grep,

find, less,

and telnet.

To mount your SUSE LINUX system using the rescue system, use the mount

point <code>/mnt</code>

. You can also use or create another

directory.

The following example demonstrates the procedure for

a system with the <code>/etc/fstab</code>

details

Example 5.1. Example /etc/fstab

Warning

Pay attention to the order of steps outlined in the following section for

mounting the various devices.

To access your entire system, mount it step by step in the

<code>/mnt</code>

directory using the following commands:

Now, access your entire system and, for example, correct mistakes

in configuration files, such as <code>/etc/fstab</code>

,

<code>/etc/passwd</code>

, and

<code>/etc/inittab</code>

. The configuration files are now located

in the <code>/mnt/etc</code>

directory instead of in

<code>/etc</code>

Before recovering lost partitions with the

fdisk program by simply

setting them up again,

make a printout of <code>/etc/fstab</code>

and the output of fdisk -l

Damaged file systems are tricky problems for the rescue system.

Generally, file systems cannot be repaired on a running

system. If you encounter serious problems, you may not even be able

to mount your root file system and the system boot may end with

<code>kernel panic</code>

. In this case, the

only way is to repair the system from the outside

using a rescue system.

The SUSE LINUX rescue system contains the utilities

reiserfsck,

e2fsck, and dumpe2fs

(for diagnosis). These should remedy most problems.

In an emergency, man pages often are not available. For this

reason, they are

If mounting an <code>ext2</code>

file system fails due to an

invalid

superblock, the e2fsck program would probably

fail, too. If this were the case, your superblock may be corrupted, too.

There are copies of the superblock located every 8192 blocks (8193, 16385,

etc.). If your superblock is corrupted, try one of the copies instead. This

is accomplished by entering the command e2fsck -f -b 8193

/dev/damaged_partition

. The -f

option forces

the file system check and overrides e2fsck's

error so that, because the superblock copy is intact, everything is fine.