bug#18132: Time for a smarter dired-guess-shell-alist-default? (dired-x.el)

[Juri Linkov]

> So now pushed to master.

Here is a patch that adds an option to use a system-dependent command
to open a file:

diff --git a/lisp/dired-aux.el b/lisp/dired-aux.el
index 47e97c96ce1..e945052b571 100644
--- a/lisp/dired-aux.el
+++ b/lisp/dired-aux.el
@@ -1329,6 +1329,7 @@ shell-command-guess-functions
           (choice (function-item shell-command-guess-dired)
                   (function-item shell-command-guess-mailcap)
                   (function-item shell-command-guess-xdg)
+                  (function-item shell-command-guess-open)
                   (function :tag "Custom function")))
   :group 'dired
   :version "30.1")
@@ -1380,6 +1381,29 @@ shell-command-guess-xdg
                   xdg-mime-apps)))
     (append xdg-commands commands)))
 
+(defcustom shell-command-guess-open
+  (cond
+   ((executable-find "xdg-open")
+    "xdg-open")
+   ((executable-find "run-mailcap")
+    "run-mailcap")
+   ((eq system-type 'ms-dos)
+    "start")
+   ((eq system-type 'cygwin)
+    "cygstart")
+   ((eq system-type 'windows-nt)
+    "open")
+   ((eq system-type 'darwin)
+    "open"))
+  "A shell command to open a file externally."
+  :type 'string
+  :group 'dired
+  :version "30.1")
+
+(defun shell-command-guess-open (commands _files)
+  "Populate COMMANDS by the `open' command."
+  (append (ensure-list shell-command-guess-open) commands))
+
 
 ;;; Commands that delete or redisplay part of the dired buffer