Yes. It gave me quite a lot of trouble when I asked it to replace "cut -d:" with pure elisp. Eventually after a few minutes I got it to work, but during real work I probably would have just written it myself if something so simple didn't work the first time I asked.

Here's the log:

    ChatGPT> Replace the cut shell command with a pure elisp implementation in this code:

    (let* ((group-command "cut -d: -f1 /etc/group") ; command to list the groups
    (group-data (with-temp-buffer
    (shell-command group-command (current-buffer))
    (sort (split-string (buffer-substring-no-properties (point-min) (point-max)) "\n") #'string<))))
      (message "Selected group: %s" (completing-read "Choose a group: " group-data nil t)))
    <shell-maker-end-of-prompt>
    (let* ((group-command "cut -d: -f1 /etc/group") ; command to list the groups
    (group-data (sort (split-string (with-output-to-string
          (call-process-shell-command group-command nil standard-output))
        "\n")
         #'string<)))
      (message "Selected group: %s" (completing-read "Choose a group: " group-data nil t)))

    ChatGPT> replace group-command with and call-process-shell-command with elisp that does the same 
    <shell-maker-end-of-prompt>
    (setq group-command "cut -d: -f1 /etc/group")
    (setq group-data (sort (split-string (shell-command-to-string group-command) "\n") #'string<))
    (message "Selected group: %s" (completing-read "Choose a group: " group-data nil t)))

    ChatGPT> What is the elisp equivalent of: cut -d: -f1 /etc/group
    <shell-maker-end-of-prompt>
    The equivalent Elisp code for `cut -d: -f1 /etc/group` is:

    (concat
     (nth 0 (split-string (with-temp-buffer
       (insert-file-contents "/etc/group")
       (buffer-string))
     "\n"))
     ":")

    ChatGPT> Give me elisp I can evaluate to check that the elisp you gave is equal to the cut call 
    <shell-maker-end-of-prompt>
    You can evaluate the following Elisp code to check that the Elisp I provided is equal to the `cut` call:

    (equal
     (concat
      (nth 0 (split-string (with-temp-buffer
        (insert-file-contents "/etc/group")
        (buffer-string))
      "\n"))
      ":")
     (shell-command-to-string "cut -d: -f1 /etc/group"))

    ChatGPT> It's not equal. the cut shell command gave a list of results. The elisp you gave only gives one result 
    <shell-maker-end-of-prompt>
    I apologize for the confusion. You're right, the Elisp code I provided only returns the first entry in `/etc/group`.

    Here's the updated code to get all group names from `/etc/group` file separated by a newline:

    (with-temp-buffer
      (insert-file-contents "/etc/group")
      (let ((groups (split-string (buffer-substring-no-properties (point-min) (point-max)) "\n")))
 (mapconcat #'(lambda (group)
   (car (split-string group ":")))
     groups
     "\n"))) 

    When you evaluate this Elisp code, it will return all the group names separated by a newline character, as the `cut -d: -f1 /etc/group` command would.

    ChatGPT> Give me elisp to check the equality of it 
    <shell-maker-end-of-prompt>
    You can use the following Elisp code to check the equality of the two commands:

    (equal
     (with-temp-buffer
       (insert-file-contents "/etc/group")
       (let ((groups (split-string (buffer-substring-no-properties (point-min) (point-max)) "\n")))
  (mapconcat #'(lambda (group)
    (car (split-string group ":")))
      groups
      "\n")))
     (shell-command-to-string "cut -d: -f1 /etc/group"))