dpkg/scripts/update-rc.d.8

.\" Hey, Emacs!  This is an -*- nroff -*- source file.
.\" Authors: Ian Jackson
.TH UPDATE\-RC.D 8 "2 March 1998" "Debian Project" "Debian/GNU Linux"
.SH NAME
update\-rc.d \- install and remove System-V style init script links
.SH SYNOPSIS
.B update\-rc.d
.RI [ -n ]
.RI [ -f ]
.IB name " remove"
.HP
.B update-rc.d
.RI [ -n ]
.RI [ -f ]
.IB name " defaults"
.RI [ NN " | " NN-start " " NN-stop ]
.HP
.B update-rc.d
.RI [ -n ]
.RI [ -f ]
.I name
.BR start | stop
.IR "NN runlevel runlevel " ...
.B .
.BR start | stop
.IR "NN runlevel runlevel " ...
.BR . " ..."
.SH DESCRIPTION
.B update-rc.d
automatically updates the System V style init script links
.BI /etc/rc runlevel .d/ NNname
to scripts
.BI /etc/init.d/ name \fR.
These are run by
.B init
when changing runlevels and are generally used to start and stop
system services such as daemons.
.I runlevel
is one of the runlevels supported by
.BR init ", " 0123456789S ,
and
.I NN
is the two-digit sequence code used by
.B init
to decide which order to run the scripts in.

This manpage documents only the usage and behaviour of
.BR update-rc.d .
For a discussion of the System V style init script arrangements please
see
.BR init (8)
and the
.IR "dpkg programmers' manual" .
.SH INSTALLING INIT SCRIPT LINKS
When run with either the
.BR defaults ", " start ", or " stop
options, update-rc.d makes links
.BI /etc/rc runlevel .d/[SK] NNname
pointing to the script
.BI /etc/init.d/ name\fR,

If any files
.BI /etc/rc runlevel .d/[SK]?? name
already exist then
.B update-rc.d
does nothing.  This is so that the system administrator can rearrange
the links, provided that they leave at least one link remaining,
without having their configuration overwritten.

If
.B defaults
is used then
.B update-rc.d
will make links to start the service in runlevels
.B 2345
and stop the service in runlevels
.BR 016 .
By default all the links will have sequence code 20, but
this can be overridden by supplying one or two
.I NN
arguments; one argument overrides the sequence code for both start and
stop links whereas of two arguments the first overrides the code for
start links and the second that for stop links.

Instead of
.B defaults
the runlevels in which to start and stop the service may be specified
explicitly using a series of sets of arguments:

Each of these sets starts with an argument
.BR start " or " stop
to specify whether start or stop links are to be created by that set.
Then follows
.IR NN ,
the sequence code number for all the links in the set, and one or more
runlevel numbers as a single argument each.  The set is terminated by
an argument
.B .
(a single full stop).

When explicit specification, rather than
.BR defaults ,
is used there will usually be one
.B start
and one
.B stop
set.  If different sequence codes are required in different runlevels
then several 
.B start
sets or several
.B stop
sets may be specified.

The script
.BI /etc/init.d/ name
must exist before
.B update-rc.d
is run to create the links.
.SH REMOVING SCRIPTS
When invoked with the
.I remove
option, update-rc.d removes any links in the
.BI /etc/rc runlevel .d
directories to the script
.BI /etc/init.d/ name\fR.
The script must have been deleted already -
.B update-rc.d
checks for this.
.B update-rc.d
is usually called from a package's post-removal script when that
script detects that its first argument is
.BR purge ,
indicating that the user has requested the configuration for the
package to be removed.
Any files in the
.BI /etc/rc runlevel .d
directories that are not symbolic links to the script
.BI /etc/init.d/ name
will be left untouched.
.SH OPTIONS
.TP
.I -n
Don't do anything, just show what we would do.
.TP
.I -f
Force removal of symlinks even if
.BI /etc/init.d/ name
still exists.
.SH EXAMPLES
Insert links using the defaults:
.nf
.B "   update-rc.d foobar defaults"
.fi
Equivalent command using explicit argument sets:
.nf
.B "   update-rc.d foobar start 20 2 3 4 5 . stop 20 0 1 6 ."
.fi
.SH BUGS

There should be a way for the system administrator to specify at least
the default start and stop runlevels to be used by
.B defaults
and possibly to override other things as well.
.SH FILES
.TP
.B /etc/init.d/
The directory containing the actual init scripts.
.TP
.B /etc/rc?.d/
The directories containing the links used by
.BR init
and managed by
.BR update-rc.d .
.TP
.B /etc/init.d/skeleton
Model for use by writers of
.B init.d
scripts.
.SH SEE ALSO
.IR "dpkg programmers manual" ,
.br
.BR /etc/init.d/skeleton ,
.br
.BR init (8).