Is it possible to extract Nexus 7 serial number through command line (e.g., ADB)? I'm possibly into a rare situation. I have a Nexus 7 LTE 2013 that suddenly stopped showing anything on the screen. It looks like turned off all the time, even the LED light does not turn on. I tried charging it in various ways and it did not help. 

I contacted Asus and they asked me for the serial number, which I don't have. They said I can find this on the box, which I don't have either. 

Using ADB, while N7 is connected to my Macbook Air, I did adb devices and it shows up a device that is "offline". When issuing the command adb get-serialno, it says unknown. It looks like the device is not dead but probably the screen is. 

Is there any tool that can get me the serial number through command line? 

Update:

I had an alarm set on the device. Today the alarm was fired and I heard the alarm ring from the device. I could only turn off the alarm by holding the power button.
The "device offline" output means that the device is detected, but it refuses any operation because the user didn't allow that particular computer to connect (secure ADB). Your device is up and running, and displaying a confirmation window on its non-functioning screen. You could try to power the device on and blindly hit the OK button after unlocking the screen, then all ADB commands should work. Alternatively, if you have used ADB with another computer, try it with that.

Also, all devices offer some kind of ID even in this state, displayed by "adb devices"; this is the serial number most of the time. See if it's the right format.

Edit: "fastboot devices" should show the serial number too. Also, it should be easy to put the N7 into fastboot mode even without a screen.