How to Auto Execute Commands and Scripts at Reboot or Startup on Linux

Linux is a powerful operating system known for its flexibility and automation capabilities. One of the most common requirements for system administrators and developers is to auto execute commands or scripts during reboot or startup. This automation ensures that essential services, applications, or maintenance tasks run without manual intervention each time the system boots.

In this detailed guide, we will explore multiple methods to configure Linux for executing scripts at system startup, reboot, login, and logout. We will cover both traditional approaches (like cron and rc.local) and modern systemd-based methods, making this tutorial distro-agnostic and useful for all Linux users.

Why Auto Execute Commands on Linux?

Setting up Auto Execute Commands is beneficial in many scenarios:

• Service Initialization: Automatically start web servers, databases, or monitoring tools.

• System Maintenance: Schedule backups, cleanup jobs, or disk checks at startup.

• Custom Configurations: Load firewall rules, mount storage drives, or tune system parameters.

• Developer Productivity: Start containers, environments, or applications automatically.

• Security Enforcement: Apply access controls or security scripts at every boot.

Without automation, administrators would need to manually repeat these tasks after every reboot, which is inefficient and prone to human error.

Methods to Auto Execute Commands at Reboot or Startup

Linux offers several ways to run commands automatically during boot or startup. Below are the most commonly used methods:

1. Using Cron’s @reboot Directive

The cron scheduler is widely used in Linux to automate recurring tasks. It also provides a special keyword @reboot, which allows you to run a script once every time the system boots.

Steps:

• Open crontab for the desired user:

crontab -e

• Add an entry with @reboot followed by the full path of your script:

@reboot /home/user/myscript.sh

• Save and exit.

Important Notes:

• Ensure the script has execute permissions:

chmod +x /home/user/myscript.sh

• If your script depends on environment variables, explicitly define them in the script or inside the crontab entry.

This method works well for lightweight tasks and is simple to implement.

2. Using /etc/rc.d/rc.local File

The rc.local file is a traditional method for executing commands at startup. Though some modern systemd-based distributions have deprecated it, it can still be enabled manually.

Steps:

• Open the rc.local file (create it if it doesn’t exist):

sudo nano /etc/rc.d/rc.local

• Add your script or command at the end of the file:

/home/user/myscript.sh

sudo chmod +x /etc/rc.d/rc.local

sudo nano /etc/systemd/system/myscript.service

• Add the following configuration:

[Unit]
Description=Run My Script at Startup
After=network.target

[Service]
ExecStart=/home/user/myscript.sh
Restart=on-failure
User=user

[Install]
WantedBy=multi-user.target

• Reload systemd and enable the service:

sudo systemctl daemon-reload
sudo systemctl enable myscript.service
sudo systemctl start myscript.service

With this method, you gain fine-grained control:

• Start, stop, or check status of the script like any other service.

• Define dependencies (e.g., run only after the network is available).

• Ensure reliability with automatic restarts.

This is the officially recommended approach for auto-executing commands in modern Linux systems.

4. Executing Scripts at User Logon and Logout

Sometimes, you may want to run commands not at boot, but at user login or logout.

• At Login: Add your script to ~/.bash_profile or ~/.profile. Example:

/home/user/myscript.sh

• At Logout: Use ~/.bash_logout. If the file doesn’t exist, create it. Example:

/home/user/cleanup.sh

This is useful for personal scripts, such as setting environment variables or cleaning up temporary files.

Example Scripts

Example 1 – Logging Date & Time at Startup:

#!/bin/bash
DATE=$(date +'%F %H:%M:%S')
echo "System booted at: $DATE" >> /home/user/bootlog.txt

Example 2 – Starting a Custom Application:

#!/bin/bash
/usr/bin/python3 /home/user/myapp.py &

Don’t forget to give execute permissions:

chmod +x /home/user/bootlog.sh