inittab.4 (2010 09)

ManualsBrandsHP ManualsSoftwareHP-UX Manpages

inittab(4) inittab(4)

NAME

inittab - script for the boot init

process

DESCRIPTION

The

/etc/inittab ﬁle supplies the script to the boot

init daemon in its role as a general process

dispatcher (see init (1M)). The process that constitutes the majority of boot

init’s process dispatching

activities is the line process

/usr/sbin/getty

that initiates individual terminal lines. Other

processes typically dispatched by boot

init are daemons and shells.

The

inittab ﬁle is composed of entries that are position-dependent and have the following format:

:rstate :action :process

Each entry is delimited by a newline; however, a backslash (

\) preceding a newline indicates a continua-

tion of the entry. Up to 1024 characters per entry are permitted. Comments can be inserted in the pro-

cess ﬁeld by starting a "word" with a

# (see sh(1)). Comments for lines that spawn getty

s are displayed

by the

who command (see who(1)). It is expected that they will contain some information about the line

such as the location. There are no limits (other than maximum entry size) imposed on the number of

entries within the inittab ﬁle.

The entry ﬁelds are:

id A one- to four-character value used to uniquely identify an entry. Duplicate entries

cause an error message to be issued, but are otherwise ignored. The use of a four-

character value to identify an entry is strongly recommended (see WARNINGS below).

rstate Deﬁnes the run level in which this entry is to be processed. Run levels correspond to a

conﬁguration of processes in the system where each process spawned by boot init is

assigned one or more run levels in which it is allowed to exist. Run levels are

represented by a number in the range 0 through 6. For example, if the system is in run

level 1, only those entries having a 1 in their rstate ﬁeld are processed.

When boot

init is requested to change run levels, all processes that do not have an

entry in the rstate ﬁeld for the target run level are sent the warning signal (

SIGTERM)

and allowed a 20-second grace period before being forcibly terminated by a kill signal

(

SIGKILL). You can specify multiple run levels for a process by entering more than one

run level value in any combination. If no run level is speciﬁed, the process is assumed to

be valid for all run levels, 0 through 6.

Three other values,

a, b and c, can also appear in the rstate ﬁeld, even though they are

not true run levels. Entries having these characters in the rstate ﬁeld are processed only

when a user init process requests them to be run (regardless of the current system run

level). They differ from run levels in that boot init can never enter "run level"

a, b,or

c. Also, a request for the execution of any of these processes does not change the current

numeric run level.

Furthermore, a process started by an

a, b,orc option is not killed when boot init

changes levels. A process is killed only if its line in inittab is marked off in the

action ﬁeld, its line is deleted entirely from inittab, or boot init goes into the single-

user state.

action A keyword in this ﬁeld tells boot

init how to treat the process speciﬁed in the process

ﬁeld. The following actions can be speciﬁed:

boot Process the entry only at boot init’s boot-time read of the inittab

ﬁle. Boot init starts the process, does not wait for its termination,

and when it dies, does not restart the process. In order for this

instruction to be meaningful, the rstate should be the default or it

must match boot init’s run level at boot time. This action is useful

for an initialization function following a hardware boot of the system.

bootwait Process the entry only at boot init’s boot-time read of the inittab

ﬁle. Boot init starts the process, waits for its termination, and,

when it dies, does not restart the process.

initdefault An entry with this action is only scanned when boot init is initially

invoked. Boot init uses this entry, if it exists, to determine which

run level to enter initially. It does this by taking the highest run level

speciﬁed in the rstate ﬁeld and using that as its initial state. If the

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (2 pages)

PAGE 1
inittab(4) inittab(4) NAME inittab - script for the boot init process DESCRIPTION The /etc/inittab file supplies the script to the boot init daemon in its role as a general process dispatcher (see init (1M)). The process that constitutes the majority of boot init’s process dispatching activities is the line process /usr/sbin/getty that initiates individual terminal lines. Other processes typically dispatched by boot init are daemons and shells.
PAGE 2
inittab(4) inittab(4) rstate field is empty, boot init enters run level 6. The initdefault entry cannot specify that boot init start in the single-user state. Additionally, if boot init does not find an initdefault entry in inittab, it requests an initial run level from the user at boot time. A iA process off If the process associated with this entry is currently running, send the warning signal (SIGTERM) and wait 20 seconds before forcibly terminating the process via the kill signal (SIGKILL).