Linux System Administration for Beginners

Operation of Running Systems

Boot reboot and shutdown a system safely

Managing a Linux system’s power state correctly ensures data integrity and gives users time to save work before the machine goes offline. In this guide, you’ll learn how to:

  • Reboot or power off immediately with systemctl
  • Force a reset when the system is unresponsive
  • Schedule shutdowns or reboots with shutdown
  • Notify logged-in users in advance

1. Managing System States with systemctl

Most modern Linux distributions use systemd, and systemctl is the primary tool to control power states.

Note

All systemctl commands require root privileges. Prepend sudo if you’re not running as root.

ActionAs RootAs Non-Root User
Reboot now# systemctl reboot$ sudo systemctl reboot
Power off now# systemctl poweroff$ sudo systemctl poweroff

Reboot

# systemctl reboot
$ sudo systemctl reboot
[sudo] password for aaron:

Power Off (Shutdown)

# systemctl poweroff
$ sudo systemctl poweroff
[sudo] password for aaron:

For more options, refer to the official systemctl documentation.


2. Forcing a Reboot or Shutdown

If your system is hung or won’t shut down cleanly, you can force the operation. Use these commands sparingly—they bypass the normal shutdown sequence and risk data loss.

Warning

Forced shutdowns do not allow applications to close gracefully. Always try a standard reboot first.

SeverityCommand
Single forcesudo systemctl reboot --force<br>sudo systemctl poweroff --force
Immediate resetsudo systemctl reboot --force --force<br>sudo systemctl poweroff --force --force

3. Scheduling with shutdown

The shutdown utility lets you schedule a shutdown or reboot and broadcast a warning message to all users.

TaskCommand Syntax
Shutdown at specific timesudo shutdown HH:MM
Shutdown after a delaysudo shutdown +<minutes>
Reboot instead of shutdownAdd -r: sudo shutdown -r HH:MM
Reboot after a delaysudo shutdown -r +<minutes>

Schedule by Clock Time

$ sudo shutdown 02:00

(Times use 24-hour format, e.g., 00002359.)

Schedule by Delay

$ sudo shutdown +15

(The system will shut down in 15 minutes.)

Reboot with shutdown

$ sudo shutdown -r 02:00
$ sudo shutdown -r +15

4. Notifying Logged-In Users

To give users advance notice, append a quoted message at the end of the shutdown command:

$ sudo shutdown -r +5 'System maintenance: scheduled reboot in 5 minutes'

This message appears on all connected terminals, allowing users to save work before the system goes down.


References and Further Reading

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