Rebooting a Linux server
The most useful command is
shutdown -r now
This reboots the system with immediate effect.
On bb3 /sbin isn't yet in the path, so it's
/sbin/shutdown -r now
shutdown -rF now
The "F" forces the server to run FSCK (disk checking utility) on startup. This can take several hours.
shutdown -rf now
The lower case "f" forces the server NOT to run FSCK (it normally does on startup) so it's a fast boot.