How to find out in which order /etc/init.d scripts are load on Debian?

There's some files in /etc/init.d/ directory:

$ ls -al /etc/init.d/ | grep -i depend
-rw-r--r--   1 root root  2739 Feb 17 05:20 .depend.boot
-rw-r--r--   1 root root  2221 Feb 17 05:20 .depend.start
-rw-r--r--   1 root root  1855 Feb 17 05:20 .depend.stop

Whenever you run update-rc.d the files will change. .depend.boot file is for S level, .depend.start is for 2 3 4 5 levels and .depend.stop for 0 1 6.

In my case, I have the following order in .depend.start:

TARGETS = killprocs motd nvidia-kernel nfs-common rsyslog privoxy virtualbox
linuxlogo acpi-fakekey binfmt-support fancontrol openvpn hddtemp cgconfig 
dropbox-container dbus dnscrypt-proxy pulseaudio atd cryptmount exim4 
qbittorrent-nox ddclient acpi-support smartmontools ssh ntp loadcpufreq acpid 
cron rsync cgrulesengd cpufrequtils bootlogs bootchart-done single rmnologin 
rc.local stop-bootlogd

You can also see why the order presents in the way you see above. Each next line looks like this:

cgrulesengd: rsyslog cgconfig

which means that cgrulesengd needs rsyslog cgconfig to be started prior.

For every runlevel (0 6) there is an folder /etc/rc[N].d

In every directory there are symbolic link either starts with an "S" or with a “K”. "S" to start e "K" to stop. The scripts are executed in a lexical sort manner of the filename, in other words S10script will be executed first than S20myscript. For example :

we have two simple scripts, the second.sh script must be execute after the fist.sh script in the current runlevel.

    root@localhost init.d]# cat /etc/init.d/first.sh 
    #!/bin/bash
    #
    echo 'I am the first'  >> /var/log/messages

    root@localhost init.d]# cat /etc/init.d/second.sh   
    #!/bin/bash
    #
    echo 'I am the second'  >> /var/log/messages

What is my current level?

    [root@localhost init.d]# runlevel 
    N 5

Now we need a symbolic link starting namely S(N)myScript for the first and S(N+1)mysecondScript:

    root@localhost rc5.d]# ln -s /etc/init.d/first.sh /etc/rc5.d/S1first
    root@localhost rc5.d]# ln -s /etc/init.d/second.sh /etc/rc5.d/S2second

We can reboot and check the messages log:

    [root@localhost ~]# cat /var/log/messages | grep "I am" -A 1 -B 1
    Dec 13 13:53:36 localhost rpc.statd[3468]: Version 1.0.9 Starting
    I am the first
    Dec 13 13:53:37 localhost hcid[3532]: Bluetooth HCI daemon
    --
    Dec 13 13:53:40 localhost automount[3689]: lookup_read_master:       lookup(nisplus): couldn't locate nis+ table auto.master
    I am the second
    Dec 13 13:53:41 localhost gpm[3785]: *** info [startup.c(95)]: 

Tested on old Centos5