How to find Serial Number?

Wonder how you can find a machine's serial number via a simple command? Especially helpful if you want to use it in a script or want to find the serial number of a remote machine. Or may be you just don't want to get under the desk to find it from behind the machine! It is as simple as this:

Windows:
wmic bios get serialnumber

Linux:

dmidecode -t system | grep Serial

Note: The above command should be run from a shell. Eg: Type cmd in Run (⊞ Win+R) for Windows.