How to start a program or script at boot time
at the right moment and with root privileges
This tutorial shows a simple way to get your programs or scripts running at boot time.
Let's imagine we want a set of programs and/or scripts to start at boot.
First we prepare the programs and the scripts.
We will call the programs from scripts so we assume from now on that we only have scripts.
We assume the name of the scripts are of the kind: script1.sh script2.sh and so on.
Those scripts will be located at the folder /usr/local/sbin.
For instance, imagine that script3.sh is a script that calls a program with several options.
Then the content of the script should be something like this:
#!/bin/bash
# I am a very basic script calling a program with some options
/usr/bin/myprogram3 -option1 -option2 -option3
Notice that we wrote the path where the program is located.
The programs or services that are started at boot time have an script in the folder /etc/init.d/. Many of the scripts already present in that directory will give you an example of the kind of things that you can do. Here's is the simplest script which is divided into two parts, code which runs when called with "start", or code that stops running when called with "stop".
#! /bin/sh
### BEGIN INIT INFO
# Provides: myprogram
# Should-Start: console-screen dbus network-manager
# Required-Start: $remote_fs $network $local_fs
# Required-Stop: $remote_fs
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: start myprogram at boot time
### END INIT INFO
#
set -e
. /lib/lsb/init-functions
PATH=/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/sbin
SCRIPT="/usr/local/sbin/script.sh"
PROGRAMNAME="myprogram"
case "$1" in
start)
$SCRIPT
;;
stop)
skill $PROGRAMNAME
;;
esac
exit 0
To use this example just do the following:
- In the line # Provides: you change myprogram by the real name of your program
- Make sure that the line PATH= contains the path of all your programs and scripts
- In the line SCRIPT="" you change script.h by the name of your scripts. If you need to execute several scripts you add lines of the type SCRIPT2="..." etc.
- Same thing for the name of the programs PROGRAMNAME. Add a line for every program of the type program1, program2 that are called from the scripts.
- After the line start) you have all the scripts that will be called at boot time. If you need to call more than one, you have to add lines of the type $SCRIPT2="....", etc.
- After the line stop) the programs should be killed. skill is not the intended action for this kind of script but it is the simplest way.
- Do not change anything else and do not miss any line you have in the example.
Once you have your script you give it a name like myprogram, give to it execution permission (chmod +x myprogram), and copy it to the folder /etc/init.d as root. Then you check that the script works by calling it as root:
sudo /etc/init.d/myprogram start:
and you check that it also stops:
sudo /etc/init.d/myprogram stop
During boot the script myprogram will be called in this way. When you stop the computer, it will also stopped in this way. If skill does not its job, the OS will stop it anyway (which is a dirty way but it is simple right?).
Now we have to tell the OS that we want our program to be be started at boot time.
There are several services and programs that are called initiated at boot time.
In our script we have a line such as # Required-Start: $remote_fs $network $local_fs.
This means that our script will be executed after the system has mounted all the filesystems and the network facility is on service.
If you want/need your script to be executed at the end of the boot, change the line # Required-Start: like this
# Required-Start: $allThe last step follows. Open a terminal and type the following:
sudo insserv myprogram
This way we ask the OS to use our script at boot time at the right moment. If we check the folder /etc/rc2.d we will see that a file of the type SXmyprogram has been added. The number X indicates the order in which every program is called.
This is a quick and a bit dirty way (but effective) of starting a program at boot time. If you want to know a bit more, check the following:
http://www.debian-administration.org/articles/28
https://wiki.debian.org/LSBInitScripts
https://wiki.debian.org/LSBInitScripts/DependencyBasedBoot
and also it is good to read the files located at /etc/init.d/README and /etc/rc2.d/README and an example of init script: /etc/init.d/skeleton. Good luck!
