update-rc.d(8)



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/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.

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.

       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  cus-
       tomized  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 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.

       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/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.

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  differ-
       ence 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  run-
       levels.

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-shut-
       down 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)

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