Open Source Software

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 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
   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/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/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).



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