Red Hat ENTERPRISE LINUX 3 Reference Manual page 22

4
To set up the user environment, the kernel executes the
1.2.4. The
/sbin/init
The program (also called
/sbin/init
the environment for the user.
When the command starts, it becomes the parent or grandparent of all of the processes that
init
start up automatically on the system. First, it runs the
the environment path, starts swap, checks the file systems, and executes all other steps required for
system initialization. For example, most systems use a clock, so on them
/etc/sysconfig/clock
if there are special serial port processes which must be initialized,
file.
/etc/rc.serial
The command then runs the
init
set up in each SysV init runlevel
and dictates that
/sbin/update
Next, the command sets the source function library,
init
system, which configures how to start, kill, and determine the PID of a program.
The program starts all of the background processes by looking in the appropriate
init
the runlevel specified as default in
to the runlevel they represent. For instance,
When booting to runlevel 5, the
mine which processes to start and stop.
Below is an example listing of the
K05innd -> ../init.d/innd
K05saslauthd -> ../init.d/saslauthd
K10psacct -> ../init.d/psacct
K10radiusd -> ../init.d/radiusd
K12mysqld -> ../init.d/mysqld
K15httpd -> ../init.d/httpd
K15postgresql -> ../init.d/postgresql
K16rarpd -> ../init.d/rarpd
K20iscsi -> ../init.d/iscsi
K20netdump-server -> ../init.d/netdump-server
K20nfs -> ../init.d/nfs
K20tomcat -> ../init.d/tomcat
K24irda -> ../init.d/irda
K25squid -> ../init.d/squid
K28amd -> ../init.d/amd
K34dhcrelay -> ../init.d/dhcrelay
K34yppasswdd -> ../init.d/yppasswdd
K35dhcpd -> ../init.d/dhcpd
K35smb -> ../init.d/smb
K35vncserver -> ../init.d/vncserver
K35winbind -> ../init.d/winbind
K36lisa -> ../init.d/lisa
K45arpwatch -> ../init.d/arpwatch
K45named -> ../init.d/named
K45smartd -> ../init.d/smartd
3. For more information on SysV init runlevels, refer to Section 1.4 SysV Init Runlevels.
4. The command is used to flush dirty buffers back to disk.
update
Program
) coordinates the rest of the boot process and configures
init
configuration file to initialize the hardware clock. Another example is
/etc/inittab
3
. Among other things, the
should be run whenever it starts a given runlevel
/etc/inittab
/etc/rc.d/rc5.d/
program looks in the
init
/etc/rc.d/rc5.d/
Chapter 1. Boot Process, Init, and Shutdown
program.
/sbin/init
/etc/rc.d/rc.sysinit
rc.sysinit
script, which describes how the system should be
/etc/inittab
/etc/rc.d/init.d/functions
. The directories are numbered to corresponds
rc
is the directory for runlevel 5.
/etc/rc.d/rc5.d/
directory:
script, which sets
reads the
rc.sysinit
will execute the
sets the default runlevel
4
.
, for the
directory for
rc
directory to deter-