Add a new user option grep-command-position

* lisp/progmodes/grep.el (grep-command): Mention it.
(grep-command-position): New user option.
(grep): Use it (bug#50502).

lisp/progmodes/grep.el

@@ -126,11 +126,20 @@ include it when specifying `grep-command'.
 
 In interactive usage, the actual value of this variable is set up
 by `grep-compute-defaults'; to change the default value, use
-\\[customize] or call the function `grep-apply-setting'."
+\\[customize] or call the function `grep-apply-setting'.
+
+Also see `grep-command-position'."
   :type '(choice string
 		 (const :tag "Not Set" nil))
   :set #'grep-apply-setting)
 
+(defcustom grep-command-position nil
+  "Where point will be put when prompting for a grep command.
+If nil, put point at the end.  If not nil, this should be the
+column number where point should be set in `grep-command'."
+  :type '(choice (const :tag "At the end" nil)
+                 natnum))
+
 (defcustom grep-template nil
   "The default command to run for \\[lgrep].
 The following place holders should be present in the string:
@@ -931,10 +940,15 @@ list is empty)."
    (progn
      (grep-compute-defaults)
      (let ((default (grep-default-command)))
-       (list (read-shell-command "Run grep (like this): "
-                                 (if current-prefix-arg default grep-command)
-                                 'grep-history
-                                 (if current-prefix-arg nil default))))))
+       (list (read-shell-command
+              "Run grep (like this): "
+              (if current-prefix-arg
+                  default
+                (if grep-command-position
+                    (cons grep-command grep-command-position)
+                  grep-command))
+              'grep-history
+              (if current-prefix-arg nil default))))))
   ;; If called non-interactively, also compute the defaults if we
   ;; haven't already.
   (when (eq grep-highlight-matches 'auto-detect)