📄 1139-1140.html
字号:
<HTML>
<HEAD>
<TITLE>Linux Complete Command Reference:File Formats:EarthWeb Inc.-</TITLE>
</HEAD>
<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">
<SCRIPT>
<!--
function displayWindow(url, width, height) {
var Win = window.open(url,"displayWindow",'width=' + width +
',height=' + height + ',resizable=1,scrollbars=yes');
}
//-->
</SCRIPT>
</HEAD>
-->
<!-- ISBN=0672311046 //-->
<!-- TITLE=Linux Complete Command Reference//-->
<!-- AUTHOR=Red Hat//-->
<!-- PUBLISHER=Macmillan Computer Publishing//-->
<!-- IMPRINT=Sams//-->
<!-- CHAPTER=05 //-->
<!-- PAGES=1103-1208 //-->
<!-- UNASSIGNED1 //-->
<!-- UNASSIGNED2 //-->
<P><CENTER>
<a href="1136-1138.html">Previous</A> | <a href="../ewtoc.html">Table of Contents</A> | <a href="1141-1143.html">Next</A></CENTER></P>
<A NAME="PAGENUM-1139"><P>Page 1139</P></A>
<TABLE>
<TR><TD>
rfc931 = timeout_in_seconds
</TD><TD>
</TD></TR><TR><TD>
rfc931 (no argument)
</TD><TD>
Look up the remote user name with the RFC
931 (ident and so on) protocol. This option is
silently ignored in case of services based on transports
other than TCP. It requires that the client system runs
an RFC 931 (ident and so on) compliant daemon and may cause noticeable delays with connections
from non-UNIX hosts. The time-out period is
optional. If no time-out is specified, a default value is taken.
</TD></TR></TABLE>
<P><B>
DIAGNOSTICS
</B></P>
<P>When a syntax error is found in an access control rule, the error is reported to the
syslog daemon; further options will be ignored, and service is denied.
</P>
<P><B>
SEE ALSO
</B></P>
<P>hosts_access(5), the default access control language
</P>
<P><B>
AUTHOR
</B></P>
<P>Wietse Venema (wietse@wzv.win.tue.nl), Department of Mathematics and Computing Science, Eindhoven University
of Technology, Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
</P>
<H3><A NAME="ch05_ 24">
inittab
</A></H3>
<P>inittab—Format of the inittab file used by the SysV-compatible
init process.
</P>
<P><B>
DESCRIPTION
</B></P>
<P>The inittab file describes which processes are started at bootup and during normal operation (such as
/etc/rc, gettys). init distinguishes multiple run levels, of which each can have its own set of processes that are started. Valid
runlevels are 0_6 and A, B, and C for ondemand entries. An entry in the
inittab file has the following format:
</P>
<!-- CODE SNIP //-->
<PRE>
id:runlevels:action:process
</PRE>
<!-- END CODE SNIP //-->
<P>Lines beginning with # are ignored.
</P>
<TABLE>
<TR><TD>
id
</TD><TD>
A unique two-character-sequence which identifies an entry in
inittab.
</TD></TR><TR><TD>
</TD><TD>
Note: For gettys or other login processes, the
id field should be the tty suffix of the corresponding
tty, such as 1 for tty1. Otherwise, the login accounting will not
work correctly. This is a bug in login and will be fixed.
</TD></TR><TR><TD>
runlevels
</TD><TD>
Describes in which run levels the specified action should be taken.
</TD></TR><TR><TD>
action
</TD><TD>
Describes which action should be taken.
</TD></TR><TR><TD>
process
</TD><TD>
Specifies the process to be executed. If the process field starts with a
+ character, init will not do utmp and wtmp accounting for that process. This is needed for
gettys that insist on doing their own utmp/wtmp housekeeping. This is also a historic bug.
</TD></TR></TABLE>
<P>Valid actions are
</P>
<TABLE>
<TR><TD>
respawn
</TD><TD>
The process will be restarted whenever it terminates (such as
getty).
</TD></TR><TR><TD>
wait
</TD><TD>
The process will be started once when the specified run level is entered and
init will wait for its termination.
</TD></TR><TR><TD>
once
</TD><TD>
The process will be executed once when the specified run level is entered.
</TD></TR><TR><TD>
boot
</TD><TD>
The process will be executed during system boot. The run level field is ignored.
</TD></TR></TABLE>
<A NAME="PAGENUM-1140"><P>Page 1140</P></A>
<TABLE>
<TR><TD>
bootwait
</TD><TD>
The process will be executed during system boot while
init waits for its termination (such as /etc/rc). The
runlevel field is ignored.
</TD></TR><TR><TD>
off
</TD><TD>
This does nothing.
</TD></TR><TR><TD>
ondemand
</TD><TD>
A process marked with ondemand will be executed whenever the specified
ondemand run level is called. However, no runlevel change will occur.
</TD></TR><TR><TD>
initdefault
</TD><TD>
An initdefault-entry specifies the run level that should be entered after system boot.
If none exists, init will ask for a runlevel on the console.
</TD></TR><TR><TD>
sysinit
</TD><TD>
The process will be executed during system boot. It will be executed before any
boot or bootwait entries.
</TD></TR><TR><TD>
powerwait
</TD><TD>
The process will be executed when
init receives the SIGPWR signal, indicating that there
is something wrong with the power. init will wait for the process to finish before continuing.
</TD></TR><TR><TD>
powerfail
</TD><TD>
As powerwait but init will not wait for the processes completion.
</TD></TR><TR><TD>
powerokwait
</TD><TD>
The process will be executed when
init receives the SIGPWR signal, provided there is a
file called /etc/powerstatus containing the word
OK. This means that the power has come back again.
</TD></TR><TR><TD>
ctrlaltdel
</TD><TD>
The process will be executed when
init receives the SIGINT signal. This means that
someone on the system console pressed the Ctrl+Alt+Del key combination. Typically, one wants
to execute some sort of shutdown either to get into single_user level or to reboot the machine.
</TD></TR></TABLE>
<P>The runlevel field may contain multiple characters for different run levels, such as
123 if the process should be started in run levels 1, 2 and 3.
Ondemand entries may contain an A, B, or C. The
runlevel field of sysinit, boot, and bootwait entries
are ignored.
</P>
<P>When the run level is changed, any running processes that are not specified for the new run level are killed, first with
SIGTERM and then with SIGKILL.
</P>
<P><B>
EXAMPLES
</B></P>
<P>This is an example of an inittab that resembles the old Linux
inittab:
</P>
<!-- CODE //-->
<PRE>
# inittab for linux
id:1:initdefault:
rc::bootwait:/etc/rc
1:1:respawn:/etc/getty 9600 tty1
2:1:respawn:/etc/getty 9600 tty2
3:1:respawn:/etc/getty 9600 tty3
4:1:respawn:/etc/getty 9600 tty4
</PRE>
<!-- END CODE //-->
<P>This inittab file executes /etc/rc during boot and starts
gettys on tty1_tty4.
</P>
<P>A more elaborate inittab with different run levels (see the comments inside) is
</P>
<!-- CODE //-->
<PRE>
#Level to run in
id:4:initdefault:
ud::boot:/etc/update
rc::bootwait:/etc/rc
cr::boot:/etc/crond
#
# level 1: getty on tty1
# level 2: getty on tty1-4
# level 3: tty1-4, dialin via modem(ttys2)
# level 4: tty1-4, ttyb
#
mr:126:once:/usr/bin/nodialin
mi:345:once:/usr/bin/dialin
1:1234:respawn:/etc/getty 9600 tty1
2:234:respawn:/etc/getty 9600 tty2
3:234:respawn:/etc/getty 9600 tty3
</PRE>
<!-- END CODE //-->
<P><CENTER>
<a href="1136-1138.html">Previous</A> | <a href="../ewtoc.html">Table of Contents</A> | <a href="1141-1143.html">Next</A></CENTER></P>
</td>
</tr>
</table>
<!-- begin footer information -->
</body></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -