Re: Control of fan-speed on Lenovo Thinkpads

[Jean Louis <bugs@gnu.support>]

* Stefan Monnier <monnier@iro.umontreal.ca> [2021-03-31 17:24]:
> > 	(let* ((sudo `(call-process "sudo" nil ,sudo-buffer t "su" "-c" "--" "root" "-c" ,command))
> > 	       (status (eval sudo))
> 
> Why?  No kitten needs to suffer here:
> 
>     (let* ((status (call-process "sudo" nil sudo-buffer t "su" "-c" "--" "root" "-c" command))

In that specific case yes. It works, I changed it. But it defeats
itself in purpose, do you see? That COMMAND is parameter to `su' which
invokes default user's shell. I don't find it bad, it just defeats the
purpose of `call-process'.

On the other hand, something like this would not work:

(call-process "dmesg" nil (get-buffer-create "*out*") t "-l info") → 1 with message "dmesg: unknown level ' info'"

but this works:

(call-process "dmesg" nil (get-buffer-create "*out*") t "-l" "info") → 0

Maybe `call-process' is not that much safer than `shell-command',
as with some dangerous arguments it could execute wrongly. I find
it beneficial that one can forget about quoting.

(call-process "echo" nil (get-buffer-create "*out*") t "-n" "Hello
there") → 0 -- works well even with new line.

(call-process "echo" nil (get-buffer-create "*out*") t "-n" "Hello \"there\" 'Somebody here' and ''' more than that.") → 0 with message: Hello "there" 'Somebody here' and ''' more than that.

For me it brings main benefit that I can forget about problems of
quoting. I will be replacing `shell-command' in those functions
where quoting is possible problem.

Example would be here, where `figlet' accepts strings but then
with `shell-command' I would need to take care of proper quoting.

(defvar figlet-history nil)
(defvar figlet-font-history nil)

(defun figlet ()
  (interactive)
  (let* ((fonts '("banner" "big" "block" "bubble" "digital"
		  "ivrit" "lean" "mini" "mnemonic" "script"
		  "shadow" "slant" "small" "smscript" "smshadow"
		  "smslant" "standard" "term"))
	 (font (completing-read "Font: " fonts nil t (car figlet-font-history) 'figlet-font-history))
	 (text (read-from-minibuffer "Text: " (car figlet-history) nil nil 'figlet-history))
	 (command (format "figlet -f %s \"%s\"" font text))
	 (figlet (shell-command-to-string command)))
    (if buffer-read-only
	(message figlet)
      (insert figlet))))

Then such can be improved so that programmer does not think of quoting:

(defun figlet ()
  (interactive)
  (let* ((fonts '("banner" "big" "block" "bubble" "digital"
		  "ivrit" "lean" "mini" "mnemonic" "script"
		  "shadow" "slant" "small" "smscript" "smshadow"
		  "smslant" "standard" "term"))
	 (font (completing-read "Font: " fonts nil t (car figlet-font-history) 'figlet-font-history))
	 (text (read-from-minibuffer "Text: " (car figlet-history) nil nil 'figlet-history)))
    (call-process "figlet" nil t nil "-f" font text)))

Where one can insert any kind of quotes in the string:

+-+-+-+-+-+-+-+ +-+-+-+-+-+
|"|t|h|a|n|k|"| |"|y|o|u|"|
+-+-+-+-+-+-+-+ +-+-+-+-+-+

or

+-+-+-+-+-+-+ +-+-+ +-+-+-+-+-+-+-+-+ +-+-+ +-+-+ +-+-+-+-+-+ +-+-+-+ +-+
|'|'|T|h|i|s| |i|s| |'|'|F|u|n|n|y|'| |\|'| |i|t| |w|o|r|k|s| |a|l|l| |-|
+-+-+-+-+-+-+ +-+-+ +-+-+-+-+-+-+-+-+ +-+-+ +-+-+ +-+-+-+-+-+ +-+-+-+ +-+
+-+-+-+-+-+-+-+-+-+-+
|||@|\|"|n|i|c|e|\|"|
+-+-+-+-+-+-+-+-+-+-+


-- 
Jean

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