There’s plenty of times you can need the serial number (aka Service Tag) from a Dell machine, but not be able to physically look at the label. It’s a server in a datacenter, it’s your laptop and it’s on a dock, etc, etc. Fortunately, there are easy commands to get the serial number right from the command line in both Windows and Linux.
From a command prompt, type:
wmic bios get serialnumber
Linux (Ubuntu and others):
From a terminal, type:
sudo dmidecode -s system-serial-number
Comments are welcome, as always.