If you're looking for a quick way to find your Dell service tag from the command line:
Use the following command to get the Dell tag:
# dmidecode -s system-serial-number
If Dell doesn't recognize that tag, try:
This will give a list of a bunch of the DMI devices that are built into the server that they can parse for the correct number.
You can then calculate the express code by translating the Service tag from base-36 to base-10. Another option is to use this website to translate:http://www.creativyst.com/Doc/Articles/HT/Dell/DellPop.htm