How to run a script during boot as root

Question

I had a script that automatically enables my wifi without using networkmanager, but I don't know how to run the script as root while the system is booting. How do I make the script run automatically during boot?

Answer 1

Place the script you want to run in the /etc/init.d directory and make the script executable.

chmod 755 myscript

Once that is done create a symbolic link in the run level directory you would like to use, for example if you wanted to run a program in the graphical runlevel 2, the default runlevel for Ubuntu, you would place it in the /etc/rc2.d directory. You just cannot place it the directory, you must signify when it will run by indicating the startup with an “S” and the execution order is important. Place it after everything else that is in the directory by giving it a higher number.

If the last script to be run is rc.local and it is named S99rc.local then you need to add your script as S99myscript.

ln -s /etc/init.d/myscript /etc/rc3.d/S99myscript

Each backward compatible /etc/rc*.d directory has symbolic links to the /etc/init.d/ directory.

Answer 2

Include the command in /etc/rc.local. It will be run whenever the user's runlevel changes.

Note: You have to put the command before the last line in /etc/rc.local that contains: "exit 0".

Answer 3

Use a crontab option to make your script run after reboot,

you can do it by adding @reboot code in cron

@reboot yourScriptPath 

will do it

Answer 4

Include your Script file to /etc/init.d/ with Executable permission then set different run level

$ update-rc.d script-name default

It will put your script on boot startup.

Answer 5

Create a text file like this in /etc/cron.d/:

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

@reboot   root    yourScriptPath

(You should replace yourScriptPath with the path to the script you want to run.)

Answer 6

This worked for me on Ubuntu 17.04:

1. create tour script file like disable_cdrom in convenient for you location. In my case home/yterle/disable_cdrom. In my case:

#!/bin/sh
eject /dev/sr0 -i 1

2. make it executable chmod 775 disable_cdrom
3. navigate to /etc/systemd/system and create there a service file. For example sudo gedit /etc/systemd/system/disable_cdrom.service

My disable_cdrom.service looks like this:

[Unit]
Description=Disable cdrom

[Service]
Type=oneshot
ExecStart=/bin/sh /home/yterle/disable_cdrom

[Install]
WantedBy=multi-user.target

Where ExecStart points to run your script with /bin/sh

Then run systemctl enable vgaoff.service to enable the systemd service