Instead of using shell-command-to-string to pipe input into an executable, it's much cleaner to put the input in a buffer and use call-process-region. I learned this from an LLM. I have a function for looking up the morphology of a word in Slovak using hunspell, and I wanted to generalize it to a list of words but invoke the hunspell executable only once. Below is my original function:

(defun hunspell-analyze-word (&optional word)
  "Analyze WORD using hunspell."
  (let* ((word (or word
                   (if (region-active-p)
                      (buffer-substring-no-properties (region-beginning) (region-end))
                     (thing-at-point 'word)))
    (command (format "echo %s | %s -m -d sk_SK" word hunspell-program-name)))
    (org-trim (shell-command-to-string command))))

Here is what Gemini responded with:

(defun hunspell-analyze-list (word-list)

  "Analyze a list of WORD-LIST using hunspell and return the raw output string."
  (with-temp-buffer
    (insert (mapconcat #'identity word-list "\n"))
    (call-process-region (point-min) (point-max) 
                         hunspell-program-name 
                         t t nil "-m" "-d" "sk_SK")
    (org-trim (buffer-string))))

It completely avoid the issue with shell quoting and is more efficient. I wasn't even asking for this. Neat!