Linux reboot Command Explained
The reboot command in Linux restarts the operating system. It is commonly used to apply updates, clear temporary issues, or reinitialize system services.
This guide provides a detailed overview of the reboot command and demonstrates how to use it for restarting a Linux machine.
Syntax of the reboot Command
The basic syntax of the reboot command is as follows:
reboot [OPTIONS]
Here, the OPTIONS define how the system will restart.
Important Note
To run the reboot command, you must either be logged in as the root user or have sudo privileges.
Usage of the reboot Command
Running the command without any additional options will immediately restart the system.
$ sudo reboot
Executing this command terminates all active processes, which may cause the loss of unsaved changes. After running it, the terminal session closes and the machine restarts.
How the reboot Command Works
The reboot command relies on systemd to interact with the init system, shutting down services before restarting the computer. It performs similar actions to the shutdown command before powering off the machine. This behavior can be overridden by using the -f (force) option, as explained in the next section.
Options for the reboot Command
The reboot command can be customized with the following options:
- –force or -f: Immediately restarts the system without completing shutdown procedures, such as unmounting drives or notifying logged-in users.
- –no-wall: Prevents the broadcast message from being displayed. Logged-in users are not warned before their sessions end.
- –no-sync or -n: Skips writing pending buffer data to disks, usually applied only in emergencies.
- –no-wtmp or -d: Prevents creating a reboot entry in the
/var/log/wtmpfile. - –wtmp-only or -w: Creates a log entry in
/var/log/wtmpwithout actually rebooting the system.
Alternative Commands to reboot
Besides the reboot command, Linux offers other ways to restart the system:
| Command | Description |
|---|---|
sudo systemctl reboot |
Uses systemd to initiate a system reboot. |
sudo shutdown -r now |
Shuts down the system and restarts it immediately. |
Conclusion
In this guide, you explored the reboot command, its syntax, usage, internal working, and available options. You also learned about alternative commands to achieve a system reboot. For more details, run:
man reboot
