Red Hat LINUX 7.2 Reference Manual page 55

Section 3.4:Init Runlevels
them to quickly move in and out of their custom configuration without disturbing the normal set of
features at the standard runlevels.
If your machine gets into a state where it will not boot due to a bad /etc/inittab or will not
let you log in because you have a corrupted /etc/passwd (or if you have simply forgotten your
password), boot into single-user mode.
If you are using LILO, you can enter single-user mode by typing linux single at the LILO boot:
prompt.
If you are using GRUB as your boot loader, you can enter single-user mode using the following steps.
• In the graphical GRUB boot loader screen, select the
edit it.
• Arrow down to the kernel line and press
• At the prompt, type single and press
• You will be returned to the GRUB screen with the kernel information. Press the
system into single user mode.
A very bare system will boot, and you will have a command shell from which you can fix things.
If this does not work, you will need to boot by typing linux init=/bin/bash at the LILO
boot: prompt. This places you at a shell prompt; note that no filesystems other than the root filesys-
tem are mounted, and the root filesystem is mounted in read-only mode. To mount it in read-write
mode (to allow editing of a broken /etc/inittab, for example) do:
mount -n /proc
mount -o rw,remount /
3.4.1 Initscript Utilities
The chkconfig utility in /sbin provides a simple command-line tool for maintaining the
/etc/rc.d/init.d directory hierarchy. It relieves system administrators from having to directly
manipulate the numerous symbolic links in the directories under /etc/rc.d.
In addition, there is ntsysv that provides a text-based interface, which you may find easier to use than
chkconfig's command-line interface.
If you prefer a graphical interface, use the serviceconf program.
All of these utilities must be run as root.
Please refer to the Official Red Hat Linux Customization Guide for more information regarding these
tools.
Red Hat Linux
to edit it.
[e]
.
[Enter]
boot label and press
[e]
key to boot the
[b]
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to