Re: Control of fan-speed on Lenovo Thinkpads

[Jean Louis <bugs@gnu.support>]

* Stefan Monnier <monnier@iro.umontreal.ca> [2021-03-30 18:03]:
> > (defun sudo (&rest arguments)
> >   "Executes list ARGUMENTS with system command `sudo'."
> >   (let ((default-directory "/sudo::"))
> >     (shell-command-to-string (string-join arguments " "))))
> 
> Please don't `string-join` arguments and please don't use a shell when
> it's not necessary: they're recipes for quoting bugs.
> Better use something like `file-process` here.

Yes, you are right, that it works well is coincidence. I think that
string-join came from earlier command which used call-process or
similar where arguments are separate.

I have improved my command, and it still works well. 

(defun sudo (command)
  "Execute COMMAND with system command `sudo'."
  (let ((not-remote (not (file-remote-p default-directory))))
    (if not-remote
	(let* ((command (format "sudo su -c -- root -c \"%s\"" command))
	       (return (shell-command-to-string command)))
	  return)
      (message "This `sudo' does not work on remote directory: %s" default-directory))))

You probably mean process-file? There is no file-process.

There is practical burden to use call-process, and it is with &rest
ARGS, as those have to be given all separately.

One echo to file and command with sudo becomes very complex, and it does not work:

(call-process "/usr/bin/sudo" nil (get-buffer-create "sudo") nil "su" "-c" "--" "root" "-c" "echo" "level" "full-speed" ">" "/proc/acpi/ibm/fan")

(call-process "/usr/bin/sudo" nil (get-buffer-create "sudo") nil "su" "-c" "--" "root" "-c" "echo" "hello" ">" "/tmp/text.txt") → 0 -- but does not produce /tmp/text.txt, so I do not know how to use it.

Then again I would like to pass a command, and not quote each part of command as arguments.

I would like something like (sudo "echo hello > /proc/file") that it works.

But for that to work, how I understand, I need to split string with spaces, remove empty strings maybe, and then pass it as list as ARGS to call-process.

(setq args '("su" "-c" "--" "root" "-c" "echo" "level" "full-speed" ">" "/proc/acpi/ibm/fan"))

(call-process "sudo" nil t t args) -> this will not work, so to
pass it as a list there, I would need to make a macro expansion?

`(call-process "sudo" nil (get-buffer-create "sudo") nil ,@args) → (call-process "sudo" nil (get-buffer-create "sudo") nil "su" "-c" "--" "root" "-c" "echo" "level" "full-speed" ">" "/proc/acpi/ibm/fan")

(defun sudo (command)
  "Execute COMMAND with system command `sudo'."
  (let ((not-remote (not (file-remote-p default-directory))))
    (if not-remote
	(let* ((sudo "sudo")
	       (args (append '("su" "-c" "--" "root" "-c") (split-string command)))
	       (status `(call-process ,sudo nil (get-buffer-create "*sudo*") t ,@args)))
	  (message "%s" status)
	  (eval status)))))

By using that above function, this will work: (sudo "ls") but this will not work:
(sudo "ls /boot /var") -- so I do not know how to expand the list properly in the function. 

I would like to get following to work in simpler way by providing string:

(sudo "echo level full-speed > /proc/acpi/ibm/fan")

-- 
Jean

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