How to change the default run level of a RedHat 9.0 or Fedora Core Linux system
During the boot process for Redhat 9.0 and Fedora Core systems
the
init command opens the
/etc/inittab file to decide what
"runlevel" the system should be booted to. The
/etc/inittab file is a plain text
file that can be opened with your favorite text editor.
The relavent section of a sample
/etc/inittab
file is as follows:
#
Default runlevel. The runlevels used by RHS are:
# 0 - halt (Do NOT
set initdefault to this)
# 1 - Single user mode
# 2 - Multiuser,
without NFS (The same as 3, if you do not have networking)
# 3 - Full multiuser
mode
# 4 - unused
# 5 - X11
# 6 - reboot (Do NOT
set initdefault to this)
#
id:3:initdefault:
The key line in the example above is:
id:3:initdefault:
This tells the init process that the default run level for the system
is run level 3. To change to a different run level simply change the
number and save the /etc/inittab file. Before doing this, however, be
absolutely sure you know which run level you want. Selecting the wrong
runlevel can have serious consequences. To help with this a detailed
description of the individual run levels is outlined in the table below:
Table 1: Linux Runlevel Descriptions
Runlevel
|
Runlevel Description
|
Runlevel 0
|
The halt runlevel - this is the
runlevel at which the system shuts down. For obvious reasons it is
unlikely you would want this as your default runlevel.
|
Runlevel 1
|
Single runlevel. This causes the
system to start up in a single user mode under which only the root user
can log in. In this mode the system does not start any networking or X
windowing, X or multi-user services. This run level is ideal for system
administrators to perform system maintenance or repair activities.
|
Runlevel 2
|
Boots the system into a
multi-user mode with text based console login capability. This runlevel
does not, however, start the network.
|
Runlevel 3
|
Similar to runlevel 2 except
that networking services are started. This is the most common runlevel
for server based systems that do not require any kind of graphical
desktop environment.
|
Runlevel 4
|
Undefined runlevel. This
runlevel can be configured to provide a custom boot state.
|
Runlevel 5
|
Boots the system into a
networked, multi-user state with X Window System capability. By default
the graphical desktop environment will start at the end of the boot
process. This is the most common run level for desktop or workstation
use.
|
Runlevel 6
|
Reboots the system. Another
runlevel that you are unlikely to want as your default.
|
