1. Use systemctl reboot
On Debian 12 or other systemd-based distributions, reboot is essentially an alias for systemctl reboot. If reboot is not found, try:
systemctl reboot
2. Run /sbin/reboot Directly
Sometimes, reboot might not be in your PATH. Try running it directly:
/sbin/reboot
If this works, your PATH might be misconfigured. Check it with:
echo $PATH
If /sbin is missing, temporarily add it:
export PATH=$PATH:/sbin:/usr/sbin
3. Check If reboot Is Missing
If the command is truly missing, reinstall it with:
apt update apt install systemd-sysv -y
The systemd-sysv package includes reboot, shutdown, and other essential commands.
4. Use shutdown Instead
If reboot is unavailable, try:
shutdown -r now
-r means reboot
now means execute immediately
If none of these solutions work, check if /sbin/reboot exists:
ls -l /sbin/reboot
If it’s missing, verify whether it was removed or replaced using:
which reboot type reboot