Many of the examples in this manual print text when they are
evaluated. If you execute example code in a Lisp Interaction buffer
(such as the buffer *scratch*) by typing C-j after the
closing parenthesis of the example, the printed text is inserted into
the buffer. If you execute the example by other means (such as by
evaluating the function
eval-region), the printed text is
displayed in the echo area.
Examples in this manual indicate printed text with ‘-|’, irrespective of where that text goes. The value returned by evaluating the form follows on a separate line with ‘⇒’.
(progn (prin1 'foo) (princ "\n") (prin1 'bar)) -| foo -| bar ⇒ bar