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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).