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3 perry 1 !!!INITTAB
5 JohnMcPherson 2
3 perry 3 ----
4 !!NAME
5
6
7 inittab - format of the inittab file used by the sysv-compatible init process
5 JohnMcPherson 8
3 perry 9 !!DESCRIPTION
10
11
12 The __inittab__ file describes which processes are
13 started at bootup and during normal operation (e.g.
5 JohnMcPherson 14 /etc/init.d/boot, /etc/init.d/rc, gettys...). init(8)
3 perry 15 distinguishes multiple ''runlevels'', each of which can
16 have its own set of processes that are started. Valid
17 runlevels are __0__-__6__ plus __A__, __B__, and
18 __C__ for __ondemand__ entries. An entry in the
19 __inittab__ file has the following format:
20
21
22 ''id'':''runlevels'':''action'':''process''
23
24
25 Lines beginning with `#' are ignored.
26
27
28 ''id''
29
30
31 is a unique sequence of 1-4 characters which identifies an
32 entry in __inittab__ (for versions of sysvinit compiled
33 with the ''old'' libc5 (
34 ''
35
36
37 Note: traditionally, for getty and other login processes,
38 the value of the ''id'' field is kept the same as the
39 suffix of the corresponding tty, e.g. __1__ for
40 __tty1__. Some ancient login accounting programs might
41 expect this, though I can't think of any.
42
43
44 ''runlevels''
45
46
47 lists the runlevels for which the specified action should be
48 taken.
49
50
51 ''action''
52
53
54 describes which action should be taken.
55
56
57 ''process''
58
59
60 specifies the process to be executed. If the process field
61 starts with a `+' character, __init__ will not do utmp
62 and wtmp accounting for that process. This is needed for
63 gettys that insist on doing their own utmp/wtmp
64 housekeeping. This is also a historic bug.
65
66
67 The ''runlevels'' field may contain multiple characters
68 for different runlevels. For example, __123__ specifies
69 that the process should be started in runlevels 1, 2, and 3.
70 The ''runlevels'' for __ondemand__ entries may contain
71 an __A__, __B__, or __C__. The ''runlevels''
72 field of __sysinit__, __boot__, and __bootwait__
73 entries are ignored.
74
75
76 When the system runlevel is changed, any running processes
77 that are not specified for the new runlevel are killed,
78 first with SIGTERM , then with
79 SIGKILL .
80
81
82 Valid actions for the ''action'' field are:
83
84
85 __respawn__
86
87
88 The process will be restarted whenever it terminates (e.g.
89 getty).
90
91
92 __wait__
93
94
95 The process will be started once when the specified runlevel
96 is entered and __init__ will wait for its
97 termination.
98
99
100 __once__
101
102
103 The process will be executed once when the specified
104 runlevel is entered.
105
106
107 __boot__
108
109
110 The process will be executed during system boot. The
111 ''runlevels'' field is ignored.
112
113
114 __bootwait__
115
116
117 The process will be executed during system boot, while
118 __init__ waits for its termination (e.g. /etc/rc). The
119 ''runlevels'' field is ignored.
120
121
122 __off__
123
124
125 This does nothing.
126
127
128 __ondemand__
129
130
131 A process marked with an __ondemand__ runlevel will be
132 executed whenever the specified __ondemand__ runlevel is
133 called. However, no runlevel change will occur
134 (__ondemand__ runlevels are `a', `b', and
135 `c').
136
137
138 __initdefault__
139
140
141 An __initdefault__ entry specifies the runlevel which
142 should be entered after system boot. If none exists,
143 __init__ will ask for a runlevel on the console. The
144 ''process'' field is ignored.
145
146
147 __sysinit__
148
149
150 The process will be executed during system boot. It will be
151 executed before any __boot__ or __bootwait__ entries.
152 The ''runlevels'' field is ignored.
153
154
155 __powerwait__
156
157
158 The process will be executed when the power goes down. Init
159 is usually informed about this by a process talking to a UPS
160 connected to the computer. __Init__ will wait for the
161 process to finish before continuing.
162
163
164 __powerfail__
165
166
167 As for __powerwait__, except that __init__ does not
168 wait for the process's completion.
169
170
171 __powerokwait__
172
173
174 This process will be executed as soon as __init__ is
175 informormed that the power has been restored.
176
177
178 __powerfailnow__
179
180
181 This process will be executed when __init__ is told that
182 the battery of the external UPS is almost empty and the
183 power is failing (provided that the external UPS and the
184 monitoring process are able to detect this
185 condition).
186
187
188 __ctrlaltdel__
189
190
191 The process will be executed when __init__ receives the
192 SIGINT signal. This means that someone on the system console
193 has pressed the __CTRL-ALT-DEL__ key combination.
194 Typically one wants to execute some sort of __shutdown__
195 either to get into single-user level or to reboot the
196 machine.
197
198
199 __kbrequest__
200
201
202 The process will be executed when __init__ receives a
203 signal from the keyboard handler that a special key
204 combination was pressed on the console
205 keyboard.
206
207
208 The documentation for this function is not complete yet;
209 more documentation can be found in the kbd-x.xx packages
210 (most recent was kbd-0.94 at the time of this writing).
211 Basically you want to map some keyboard combination to the
212
213
214 alt keycode 103 = !KeyboardSignal
215 !!EXAMPLES
216
217
218 This is an example of a inittab which resembles the old
219 Linux inittab:
220
221
222 # inittab for linux
223 id:1:initdefault:
224 rc::bootwait:/etc/rc
225 1:1:respawn:/etc/getty 9600 tty1
226 2:1:respawn:/etc/getty 9600 tty2
227 3:1:respawn:/etc/getty 9600 tty3
228 4:1:respawn:/etc/getty 9600 tty4
229
230
231 This inittab file executes __/etc/rc__ during boot and
232 starts gettys on tty1-tty4.
233
234
235 A more elaborate __inittab__ with different runlevels
236 (see the comments inside):
237
238
239 # Level to run in
240 id:2:initdefault:
241 # Boot-time system configuration/initialization script.
242 si::sysinit:/etc/init.d/rcS
243 # What to do in single-user mode.
244 ~:S:wait:/sbin/sulogin
245 # /etc/init.d executes the S and K scripts upon change
246 # of runlevel.
247 #
248 # Runlevel 0 is halt.
249 # Runlevel 1 is single-user.
250 # Runlevels 2-5 are multi-user.
251 # Runlevel 6 is reboot.
252 l0:0:wait:/etc/init.d/rc 0
253 l1:1:wait:/etc/init.d/rc 1
254 l2:2:wait:/etc/init.d/rc 2
255 l3:3:wait:/etc/init.d/rc 3
256 l4:4:wait:/etc/init.d/rc 4
257 l5:5:wait:/etc/init.d/rc 5
258 l6:6:wait:/etc/init.d/rc 6
259 # What to do at the
260 !!FILES
261
262
263 /etc/inittab
264 !!AUTHOR
265
266
267 __Init__ was written by Miquel van Smoorenburg
268 (miquels@cistron.nl). This manual page was written by
269 Sebastian Lederer (lederer@francium.informatik.uni-bonn.de)
270 and modified by Michael Haardt
271 (u31b3hs@pool.informatik.rwth-aachen.de).
272 !!SEE ALSO
273
274
275 init(8), telinit(8)
276 ----
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