How to Restart Ubuntu from the Terminal

reboot

Restart now:

sudo reboot now

Or simply:

sudo reboot

Force an immediate restart without stopping services cleanly (a last resort):

sudo reboot -f

shutdown

Restart in one minute:

sudo shutdown -r

Restart after a number of minutes:

sudo shutdown -r +min

Example, in 4 minutes:

sudo shutdown -r +4

Cancel it:

sudo shutdown -c

systemctl

sudo systemctl reboot

init

sudo init 6

telinit

sudo telinit 6

REISUB

When the system is frozen and does not react to the mouse or the keyboard, hold Alt and SysRq (Print Screen) and type these keys slowly, one by one:

• R switches the keyboard to raw mode.
• E sends the terminate signal to all processes except init.
• I sends the kill signal to all processes except init.
• S syncs all file systems to the disk.
• U remounts file systems as read-only.
• B reboots the system.

Remember it as "Reboot Even If System Utterly Broken". The magic SysRq keys must be enabled on the system.

Before you reboot a server

• Save your work and tell other users, for example with sudo shutdown -r +10 "Rebooting for updates".
• Check that services start at boot with systemctl is-enabled service.
• Keep console or panel access in case the server does not come back.

Quick recap

• sudo reboot is the quickest way.
• Use shutdown -r +N to schedule it and shutdown -c to cancel.