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



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

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

       update-rc.d [-n] name defaults

       update-rc.d [-n] 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  run‐
       levels;  they  are generally used to start and stop system services such as daemons.  run‐
       level 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  Man‐
       ual.


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/rcrun‐
       level.d/[SK]NNname that point to the script /etc/init.d/name, using  runlevel  and  depen‐
       dency information from the init.d script LSB comment header.

       If  any files named /etc/rcrunlevel.d/[SK]??name already exist then update-rc.d does noth‐
       ing.  The program was written this way so that it will never change an existing configura‐
       tion,  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.

       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 symbolic links from S to K.

       The script /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/rcrun‐
       level.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/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.

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

       -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
       runlevels 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 http://bugs.debian.org/sysv-rc.

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



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