add missing obj arg.
addressbook read/write roundtrip works!

$ ./addressbook.sh write | ./addressbook.sh read
Reading message from stdin
  (note, this will likely fail)
  (if you are on windows,     )
  (see README.                )

  mobile phone: 555-1212
  student at: MIT
  home phone: 555-4567
  work phone: 555-7654
  unemployed