Exporting contacts via adb I have a phone whose screen broke, but I'd like to export its contacts to .vcf so I can import them to another phone. I usually do this with the built-in import/export function in the Contacts app overflow menu, but without a screen it is inaccessible. Is it possible to do this via adb?
Yes and no, if your screen is working, you can use an org cable or a microusb to USB adapter and plug a mouse into your phone.  Works like a dream. If you have no visual display that is another matter.  


You must have already enabled usb debugging 
You must have already connected the phone to your computer and verified it. 


It's extremely difficult

If you have done the above then you send the adb pull request to the correct location, and with that recieved file you will have to do a couple things. 


Find out the correct format for your phone's contacts db.
Figure out the correct conversation script to convert to new phones db format


Send converted file to new phone



Edit
Forgot to mention you missy have already rooted your phone to access the contacts file

Easiest Solution
Just make sure your contacts are backed up to and linked to your gmail email.