Manual: update-rc.d

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update-rc.d(8) Debian GNU/Linux update-rc.d(8)

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

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

update-rc.d name defaults

update-rc.d name defaults-disabled

update-rc.d name disable|enable [ S|2|3|4|5 ]

DESCRIPTION
update-rc.d updates the System V style init script links /etc/rcrunlevel.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.

INSTALLING INIT SCRIPT LINKS
update-rc.d requires dependency and runlevel information to be provided in the init.d script LSB comment header of
all init.d scripts. See the insserv(8) manual page for details about the LSB header format.

When run with the defaults option, update-rc.d makes links named /etc/rcrunlevel.d/[SK]NNname that point to the
script /etc/init.d/name, using runlevel and dependency information from the init.d script LSB comment header.

When run with the defaults-disabled option, update-rc.d makes links named /etc/rcrunlevel.d/KNNname that point to the
script /etc/init.d/name, using dependency information from the init.d script LSB comment header. This means that the
init.d script will be disabled (see below).

If any files named /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 admin‐
istrator. The program will only install links if none are present, i.e., if it appears that the service has never
been installed before.

Older versions of update-rc.d also supported start and stop options. These options are no longer supported, and are
now equivalent to the defaults option.

A common system administration error is to delete the links with the thought that this will "disable" the service,
i.e., that this will prevent 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 sym‐
bolic links from S to K. .P The script .BI /etc/init.d/ name must exist before update-rc.d is run to create the
links.

REMOVING SCRIPTS
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. .P 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/rcrunlevel.d directories that are not symbolic links to the script
/etc/init.d/name will be left untouched.

DISABLING INIT SCRIPT START LINKS
When run with the disable [ S|2|3|4|5 ] options, update-rc.d modifies existing runlevel links for the script
/etc/init.d/name by renaming start links to stop links with a sequence number equal to the difference of 100 minus
the original sequence number.

When run with the enable [ S|2|3|4|5 ] options, update-rc.d modifies existing runlevel links for the script
/etc/init.d/name by renaming stop links to start links with a sequence number equal to the positive difference of
current sequence number minus 100, thus returning to the original sequence number that the script had been installed
with before disabling it. .P Both of these options only operate on start runlevel links of S, 2, 3, 4 or 5. If no
start runlevel is specified after the disable or enable keywords, the script will attempt to modify links in all
start runlevels.

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

EXAMPLES
Insert links using the defaults:
update-rc.d foobar defaults

The equivalent dependency header would have start and stop dependencies on $remote_fs and $syslog, and start in run‐
levels 2-5 and stop in runlevels 0, 1 and 6.

Remove all links for a script (assuming foobar has been deleted already):
update-rc.d foobar remove

Example of disabling a service:
update-rc.d foobar disable

Example of a command for installing a system initialization-and-shutdown script:
update-rc.d foobar defaults

Example of a command for disabling a system initialization-and-shutdown script:
update-rc.d foobar disable

BUGS
See and .

FILES
/etc/init.d/
The directory containing the actual init scripts.

/etc/rc?.d/
The directories containing the links used by init and managed by update-rc.d .

/etc/init.d/skeleton
Model for use by writers of init.d scripts.

SEE ALSO
Debian Policy Manual,
/etc/init.d/skeleton,
insserv(8),
init(8)

Author
Ian Jackson, Miquel van Smoorenburg

License: GNU General Public License v2 or Later (GPLv2+)

14 November 2005 update-rc.d(8)

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Manual: update-rc.d

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