Re: /etc/init.d/ - add/remove services

[Thomas Hood <jdthood@yahoo.co.uk>]

Note that the expectation of the System V init system is
that every service have either an S or a K symlink in each
runlevel.  If there is no symlink for a service in a particular
runlevel then the behavior of sysv's invoke-rc.d is undefined
for that service in that runlevel.  Methods of shutting off
services must take that into account.

Suppose you have service foo that is S20 in runlevel 2 and
you want to shut it off.  You should do something like:

    /etc/rc2.d/$ mv S20foo K80foo_originallyS20

As someone has already pointed out, update-rc.d is intended for
use by maintainer scripts.  It allows maintainer scripts to 
work independently of which init system is in use, whether it
is the System V init system, file-rc or some other.  The
local administrator need not use update-rc.d to change sysv
symlinks.

-- 
Thomas Hood <jdthood@yahoo.co.uk>