diff --git a/doc/content-for-reference.html b/doc/content-for-reference.html
index 9102a52ec..1e609c0f4 100644
--- a/doc/content-for-reference.html
+++ b/doc/content-for-reference.html
@@ -413,7 +413,8 @@ POKI_RUN_COMMAND{{mlr --opprint reorder -e -f i,b data/small}}HERE
 
 POKI_RUN_COMMAND{{mlr sort --help}}HERE
 
-<p/>xxx write up after -n/-r.
+<p/>Example:
+POKI_RUN_COMMAND{{mlr --opprint sort -f a -nr x data/small}}HERE
 
 <!-- ================================================================ -->
 <h2>stats1</h2>
diff --git a/doc/reference.html b/doc/reference.html
index 17d88bc96..7cf6a820e 100644
--- a/doc/reference.html
+++ b/doc/reference.html
@@ -1119,7 +1119,20 @@ Example:
 </div>
 <p/>
 
-<p/>xxx write up after -n/-r.
+<p/>Example:
+<p/>
+<div class="pokipanel">
+<pre>
+$ mlr --opprint sort -f a -nr x data/small
+a   b   i x                   y
+eks pan 2 0.7586799647899636  0.5221511083334797
+eks wye 4 0.38139939387114097 0.13418874328430463
+pan pan 1 0.3467901443380824  0.7268028627434533
+wye pan 5 0.5732889198020006  0.8636244699032729
+wye wye 3 0.20460330576630303 0.33831852551664776
+</pre>
+</div>
+<p/>
 
 <!-- ================================================================ -->
 <a id="stats1"/><h2>stats1</h2>