How to start an application automatically on boot

Question

I am new to Linux & looking forward to start application (which toggles a led every 10 sec). I have written the application program & it is working fine but now I want to start it automatically on boot.

The documentation here says to copy the startup script to the /etc/init.d directory and make a symbolic link to the copied script in the rc.d directory.

What should be the extension and name of these script files? Can we manually add the symbolic link in rc.d or is there some specific procedure for this?

Any suggestion how to achieve it?

Answer 1

Here's the excerpt from http://www.debian-administration.org/articles/28 which seems to answer your question.

Note: In the example script below just add a call to the "start)" section to actually launch your program. You can test the script's functionality without rebooting the system: call it with the full path and giving it a parameter of "start" or "stop"

Here goes:

Debian uses a Sys-V like init system for executing commands when the system runlevel changes - for example at bootup and shutdown time.

If you wish to add a new service to start when the machine boots you should add the necessary script to the directory /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 a very simple script which is divided into two parts, code which always runs, and code which runs when called with "start" or "stop".

#! /bin/sh
# /etc/init.d/blah
#

# Some things that run always
touch /var/lock/blah

# Carry out specific functions when asked to by the system
case "$1" in
  start)
    echo "Starting script blah "
    echo "Could do more here"
    ;;
  stop)
    echo "Stopping script blah"
    echo "Could do more here"
    ;;
  *)
    echo "Usage: /etc/init.d/blah {start|stop}"
    exit 1
    ;;
esac

exit 0

Once you've saved your file into the correct location make sure that it's executable by running "chmod 755 /etc/init.d/blah".

Then you need to add the appropriate symbolic links to cause the script to be executed when the system goes down, or comes up.

The simplest way of doing this is to use the Debian-specific command update-rc.d:

root@skx:~# update-rc.d blah defaults
 Adding system startup for /etc/init.d/blah ...
   /etc/rc0.d/K20blah -> ../init.d/blah
   /etc/rc1.d/K20blah -> ../init.d/blah
   /etc/rc6.d/K20blah -> ../init.d/blah
   /etc/rc2.d/S20blah -> ../init.d/blah
   /etc/rc3.d/S20blah -> ../init.d/blah
   /etc/rc4.d/S20blah -> ../init.d/blah
   /etc/rc5.d/S20blah -> ../init.d/blah

Answer 2

Newer versions of linux support systemd (as @AlexanderShcheblikin said). It has more features and is more portable than debian-specific solution.

Please read this really great guide.

Here is a quick reference of the bare minimum needed:

1. A script (e.g. myscript.sh) with executable permissions.
2. A Unit file (e.g. myservice.service) with ".service" extension in /etc/systemd/system with 644 permissions that contains the command to execute the script. For example,

:

[Unit]
Description=Example systemd service.

[Service]
Type=simple
ExecStart=/bin/bash /path/to/myscript.sh

[Install]
WantedBy=multi-user.target

3. Run the command sudo systemctl enable myservice to enable it to start on boot.

Answer 3

Using crontab is much easier.

Use crontab -e to edit user's crontab.
Add following line at the end:

@reboot <command>

Examples:

• @reboot my_script.sh
• @reboot python my_script.py arg1 arg2

Finally, use crontab -l to make sure your script was added to the list.

---

Update:

For example, this one liner will add a job that runs script.sh on every reboot:

crontab -l > file; echo "@reboot /home/user/script.sh" >> file; crontab file; rm file;

credit goes to: Gumby The Green Jul 16 '19 at 10:20

https://stackoverflow.com/users/9364000/gumby-the-green

Answer 4

The best way is to check package source of your distribution for a regular system service, e.g. for OpenSSH - you'll see what the good practices are. After all, one of the reasons behind open-source is to be able to learn from the sources.

Answer 5

Use Supervisor, an effective program that manages and logs the startup applications with arguments. Learn more from http://supervisord.org/running.html and (Follow the installation instruction.

Create a conf file at /etc/supervisor/conf.d/{PROGRAM_NAME}.conf and Here is the code,

[program:{PROGRAM_NAME}]
command=/usr/bin/{PROGRAM_NAME} -arg1 -arg2
autostart=true  
autorestart=true  
stderr_logfile=/var/log/supervisor/{PROGRAM_NAME}.err.log  
stdout_logfile=/var/log/supervisor/{PROGRAM_NAME}.out.log  

Then execute from cmd line:

supervisorctl reload

Answer 6

The other answers will work great for developers. But if you'd like to enable and disable your service within the "Startup Applications" settings GUI on Debian-based desktop OS (Ubuntu|Mint) you can create an App in /etc/xdg/autostart/:

/etc/xdg/autostart/blinky.desktop

[Desktop Entry]
Type=Application
Name=Blinky LED Service
Comment=Launch a background service (daemon) to blink an LED every 10 seconds.
Exec=nohup bash -c "$HOME/blinky.sh >> $HOME/blinky.log" &
Icon=
Terminal=true
Categories=
NoDisplay=false
StartupNotify=false
Encoding=UTF-8
StartupNotify=false
X-GNOME-Autostart-Delay=5
X-MATE-Autostart-Delay=5

That should create a "Blinky LED Service" app in your settings for Startup Applications:

Your blinky.sh app can be any executable you like:

~/blinky.sh

#!/usr/bin/env bash
i=0
while [ $i -le 2 ] ; do
  echo "$i LED ON"
  sleep .1
  echo "$i LED OFF"
  sleep 9.9
  ((i++))
done

Make sure your app is executable: chmod +x ~/blinky.sh