How do I reboot a Linux system using the command line?

Shutting down or rebooting a Linux system from the terminal is one of the most basic activities of every system administrator, done for applying necessary changes, resolving issues, or routine maintenance. This article explains the main commands and procedures for rebooting a Linux system.

Basic Reboot Command

The easiest Linux booting method is the reboot command. This command will reboot the Linux system. This command can be run under the root account since undertaking this command implies modifying the current system environment.

sudo reboot

This command immediately initiates a system reboot. The sudo prefix is crucial as it grants the necessary permissions to act.

Using the Shutdown Command

Another common method to reboot a Linux system is through the shutdown command. This command allows for more controlled shutdowns and reboots. To reboot the system immediately, you can use:

sudo shutdown -r now

Here, the -r option tells the system to reboot, while now indicates that the action should be taken immediately. The shutdown command can also be scheduled later by replacing now with a specific time (e.g., +5 for five minutes later) or a specific time format (e. g. , hh: MM is also referred to (mm).

Systemd and systemctl

On modern distributions based on the Linux operating system that utilizes systems as their init system, systemctl is an effective means of controlling system states; it also pertains to rebooting. Usually, to reboot the system using systemctl, the command is:

sudo systemctl reboot

This command effectively halts all processes and sends a reset signal to the motherboard, similar to the reboot command but integrated into the system framework.

Alternative Methods

In addition to the commands above, there are alternative methods to reboot a Linux system:

1. Init Command: For systems using SysVinit, the command to reboot is:

sudo init 6

This command corresponds to runlevel 6, designated for rebooting the system.

2. Using /proc Filesystem: A more advanced method involves writing directly to the /proc filesystem. To enable the SysRq system, you can execute:

echo 1 | sudo tee /proc/sys/kernel/sysrq

Then, to reboot the system, you can use:

echo b | sudo tee /proc/sysrq-trigger

This approach is usually not advised for regular use but can be useful during emergencies.

Best Practices for Rebooting

It is recommended to create a backup of important data before starting a reboot to avoid data loss in case of any unforeseen problems during the reboot. Furthermore, informing users about the upcoming restart can prevent interruptions, particularly on systems with multiple users.

Conclusion

Rebooting a Linux system via the command line is straightforward, with several commands available to suit different needs. The reboot and shutdown commands are the most commonly used, while Systemctl provides a modern approach for systems running systems. Understanding these commands and their options is essential for effective Linux system administration, ensuring reboots are performed safely and efficiently.

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