How to Restart Ubuntu from the Terminal?

This article provides a quick overview of the commands used to reboot an Ubuntu system directly from the command line. You will learn the standard, safest commands for immediate restarts, how to schedule a reboot for a later time, and how to safely force a restart if your system becomes unresponsive.

The Standard Restart Command

The most common and safest way to restart an Ubuntu system from the terminal is by using the shutdown command with the --reboot flag (or -r). Because restarting affects system-wide operations, you must precede the command with sudo to grant administrative privileges.

sudo shutdown -r now

Alternatively, you can use the shorter, dedicated reboot command, which achieves the exact same result:

sudo reboot

Both of these commands signal the operating system to gracefully close all running applications, save ongoing processes, and safely cycle the power.

Scheduling a Delayed Restart

If you are managing a server or working on a shared system, you might want to postpone the restart to give other users time to save their work. The shutdown command allows you to specify a time delay in minutes or set a specific 24-hour timestamp.

• To restart in 10 minutes:

sudo shutdown -r +10 "System restarting for updates in 10 minutes!"

• To restart at a specific time (e.g., 2:30 AM):

sudo shutdown -r 02:30

The optional string message in quotation marks will be broadcasted to all active terminal sessions on the machine. If you need to cancel a scheduled reboot before it happens, simply run:

sudo shutdown -c

Alternative and Emergency Restart Methods

In some scenarios, such as headless server management or system freezes, you might need alternative approaches to initiate a reboot.

Using systemd

Modern Ubuntu releases utilize systemd as their init system. You can talk directly to the system manager to trigger a restart:

sudo systemctl reboot

The Emergency Magic SysRq Method

If your Ubuntu desktop or server completely freezes and traditional terminal commands do not respond, you can trigger a low-level reboot using the Linux kernel’s Magic SysRq key combination. This safely flushes data to the disks and reboots without corrupting the file system.

While holding down the Alt and SysRq (often the Print Screen) keys, slowly type the following sequence of letters, pausing for a second between each:

R - E - I - S - U - B

This forces the system to regain control of the keyboard, terminate running processes, sync your hard drives, and safely initiate a hardware reset.