Thursday, 21 June 2007



关于runlevel N和/etc/rcN.d的关系.

只要进入rc3.d 更改gdm前面的s为k,这样,当再init 3的时候,就和fedora效果一样,进入text command界面.

如果要修改默认runlevel,更改/etc/event.d/rc-default.d,在最后一行加入你想要的runLEVEL,比如:telinit 3


UPDATE-RC.D(8) sysv-rc UPDATE-RC.D(8)


update-rc.d - install and remove System-V style init script links


update-rc.d [-n] [-f] name remove

update-rc.d [-n] name defaults|multiuser [NN | SS KK]

update-rc.d [-n] name start|stop NN runlevel [runlevel]... .

start|stop NN runlevel [runlevel]... . ...


update-rc.d updates the System V style init script links /etc/rcrun‐

level.d/NNname whose target is the script /etc/init.d/name. These

links are run by init when it changes runlevels; they are generally

used to start and stop system services such as daemons. runlevel is

one of the runlevels supported by init, namely, 0123456789S, and NN is

the two-digit sequence number that determines where in the sequence

init will run the scripts.

This manpage documents only the usage and behaviour of update-rc.d.

For a discussion of the System V style init script arrangements please

see init(8) and the Debian Policy Manual.

Please note that this program was designed for use in package main‐

tainer scripts and, accordingly, has only the very limited functional‐

ity required by such scripts. System administrators are not encouraged

to use update-rc.d to manage runlevels. They should edit the links

directly or use runlevel editors such as sysv-rc-conf and bum instead.


When run with either the defaults, multiuser, start, or stop options,

update-rc.d makes links /etc/rcrunlevel.d/[SK]NNname that point to the

script /etc/init.d/name.

If any files /etc/rcrunlevel.d/[SK]??name already exist then update-

rc.d does nothing. The program was written this way so that it will

never change an existing configuration, which may have been customized

by the system administrator. The program will only install links if

none are present, i.e., if it appears that the service has never been

installed before.

A common system administration error is to delete the links with the

thought that this will "disable" the service, i.e., that this will pre‐

vent the service from being started. However, if all links have been

deleted then the next time the package is upgraded, the package’s

postinst script will run update-rc.d again and this will reinstall

links at their factory default locations. The correct way to disable

services is to configure the service as stopped in all runlevels in

which it is started by default. In the System V init system this means

renaming the service’s symbolic links from S to K.

If defaults is used then update-rc.d will make links to start the ser‐

vice in runlevels 2345 and to stop the service in runlevels 016. If

multiuser is used then update-rc.d will make links to start the service

in runlevels 2345 and top stop the service in only runlevel 1. By

default all the links will have sequence number 20, but this can be

overridden by supplying one NN or two SS and KK arguments to either

defaults or multiuser; a single argument overrides the sequence number

for both start and stop links whereas a pair of arguments overrides the

sequence numbers for start and stop links, respectively.

As a rule of thumb, the sequence number of the stop link should 100

minus the sequence number of the start link; this causes services to be

stopped in the opposite order to that in which they are started. Obvi‐

ously, therefore, the default stop sequence number should be 80.

Defaulting to 20, as update-rc.d does, is an old bug that cannot be

fixed because of the risk of breaking things.

Instead of defaults or multiuser one can give one or more sets of argu‐

ments specifying particular runlevels in which to start or stop the

service. Each of these sets of arguments starts with the keyword start

or stop and a sequence number NN, followed by one or more runlevel num‐

bers. The set is terminated by a solitary full stop character. When

explicit specification, rather than defaults, is used there will usu‐

ally be one start and one stop set. If different sequence codes are

required in different runlevels then several start sets or several stop

sets may be specified. If this is done and the same runlevel is named

in multiple sets then only the last one counts. Therefore it is not

possible to create multiple start or multiple stop links for a service

in a single runlevel directory.

The script /etc/init.d/name must exist before update-rc.d is run to

create the links.


When invoked with the remove option, update-rc.d removes any links in

the /etc/rcrunlevel.d directories to the script /etc/init.d/name. The

script must have been deleted already. If the script is still present

then update-rc.d aborts with an error message.

update-rc.d is usually called from a package’s post-removal script when

that script is given the purge argument. Any files in the /etc/rcrun‐

level.d directories that are not symbolic links to the script

/etc/init.d/name will be left untouched.


-n Don’t do anything, just show what we would do.

-f Force removal of symlinks even if /etc/init.d/name still exists.


Insert links using the defaults:

update-rc.d foobar defaults

Equivalent command using explicit argument sets:

update-rc.d foobar start 20 2 3 4 5 . stop 20 0 1 6 .

Insert links for a service that should be running during multi-user

mode, but that does not need to be explicitly stopped on shutdown:

update-rc.d foobar multiuser

Equivalent command using explicit argument sets:

update-rc.d foobar start 20 2 3 4 5 . stop 20 1 .

More typical command using explicit argument sets:

update-rc.d foobar start 30 2 3 4 5 . stop 70 0 1 6 .

Remove all links for a script (assuming foobar has been deleted


update-rc.d foobar remove

Example of disabling a service:

update-rc.d -f foobar remove

update-rc.d foobar stop 20 2 3 4 5 .

Example of a command for installing a system initialization-and-shut‐

down script:

update-rc.d foobar start 45 S . start 31 0 6 .

Example of a command for disabling a system initialization-and-shutdown


update-rc.d -f foobar remove

update-rc.d foobar stop 45 S .


The multiuser option is an Ubuntu-extension intended to reduce the

amount of time spent stopping services during shutdown and reboot that

have no particular requirement to be explicitly stopped.

Unless your init script does something in the stop command that is more

than just sending the TERM or KILL signal to the running process, you

should strongly consider using multiuser instead of defaults.





The directory containing the actual init scripts.


The directories containing the links used by init and managed by



Model for use by writers of init.d scripts.


Debian Policy Manual,


sysv-rc-conf(8), bum(8), init(8).

Debian Project 14 November 2005 UPDATE-RC.D(8)

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