From a Mac OS command line, I'm looking for a command that will read my address book card and print my email address to stdout.
Doing it via an
osascript command would be fine.
What you are looking for is contacts.
ABFind from iHarder is your friend.
contacts (as mentioned in the other answer is great app, but its not compatible to osx versions newer than 10.7
ABFind runns just fine on 10.11 and returns a sort-of json response