Doc: http://http://docs.oracle.com/javase/8/docs/technotes/guides/scripting/nashorn/shell.html

Section: 4.5 Additional Nashorn Built-in Functions

Only "echo", "readLine" and "readFully" functions are defined only for (shell) -scripting mode. Other extensions like quit, exit, load, loadWithNewGlobal, Object.bindProperties are always available. These don't require -scripting mode.