Section 2.1 of the tutorial describes using import sys; sys.exit() if ^D
or ^Z doesn't work. However, both quit() and exit() work, as documented
in the "Built-in Constants" section of the Library documentation. Is
there something about them that should be hidden from the ordinary user
that they aren't used in place of the import sys; sys.exit()
combination? Seems easier to just say use "quit() or exit()", especially
for beginners following the tutorial who won't know what import or sys
are, or even the dot notation.