Writing “Hello World” in Emacs?

Question

I would like to write a few Unix scripts in Emacs Lisp. However, there doesn\'t seem to be a clean way to write to STDOUT so I can redirect the results to a file or pipe the ou

Answer 1

As David Antaramian says, you probably want princ.

Also, message supports a format control string (akin to printf in C) that is adapted from format. So, you may eventually want to do something like

(princ (format "Hello, %s!\n" "World"))

As a couple of functions plus demonstration:

(defun fmt-stdout (&rest args)
  (princ (apply 'format args)))
(defun fmtln-stdout (&rest args)
  (princ (apply 'format
                (if (and args (stringp (car args)))
                    (cons (concat (car args) "\n") (cdr args))
                  args))))

(defun test-fmt ()
  (message "Hello, %s!" "message to stderr")
  (fmt-stdout "Hello, %s!\n" "fmt-stdout, explict newline")
  (fmtln-stdout "Hello, %s!" "fmtln-stdout, implicit newline"))

Answer 2

Seems like you want princ instead of print. So, basically:

(princ "Hello world! I'm writing to STDOUT but I'm not in quotes!")

However, one caveat is that princ does not automatically terminate the output with \n.