--- a/prettyprint.rst	Wed Nov 14 16:15:18 2018 +0200
+++ b/prettyprint.rst	Thu Nov 15 14:18:37 2018 +0200
@@ -48,7 +48,11 @@
 
   $ xmllint --format file.xml
 
-or in Emacs::
+Pretty print XMLs in place::
+
+  for f in *.xml; do xmllint -o $f --format $f; done
+
+In Emacs::
 
   : C-x h C-u M-| xmllint --format - <RET>