add sort-lines arg, reverse func and key binding

layers/+distributions/spacemacs-base/funcs.el

@@ -825,12 +825,19 @@ With negative N, comment out original line and use the absolute value."
         (while (re-search-forward "^\\(.*\n\\)\\1+" end t)
           (replace-match "\\1"))))))
 
-(defun spacemacs/sort-lines ()
-  "Sort lines in region or current buffer"
+(defun spacemacs/sort-lines (&optional reverse)
+  "Sort lines in a region or the current buffer.
+A non-nil argument sorts in reverse order."
+  (interactive "P")
+  (let* ((region-active (or (region-active-p) (evil-visual-state-p)))
+         (beg (if region-active (region-beginning) (point-min)))
+         (end (if region-active (region-end) (point-max))))
+    (sort-lines reverse beg end)))
+
+(defun spacemacs/sort-lines-reverse ()
+  "Sort lines in reverse order, in a region or the current buffer."
   (interactive)
-  (let ((beg (if (region-active-p) (region-beginning) (point-min)))
-        (end (if (region-active-p) (region-end) (point-max))))
-    (sort-lines nil beg end)))
+  (spacemacs/sort-lines -1))
 
 ;; BEGIN linum mouse helpers
 

layers/+distributions/spacemacs-base/keybindings.el

@@ -437,6 +437,7 @@
   "xjr" 'set-justification-right
   "xld" 'spacemacs/duplicate-line-or-region
   "xls" 'spacemacs/sort-lines
+  "xlS" 'spacemacs/sort-lines-reverse
   "xlu" 'spacemacs/uniquify-lines
   "xtc" 'transpose-chars
   "xtl" 'transpose-lines