doc: Fix a typo in an example

diff --git a/doc/rrdgraph_rpn.pod b/doc/rrdgraph_rpn.pod
index 8a7b5bc0776365a06d9cf19cc1e63a1e7283c9df..3ee61d525f6f60adacc095505613325d5ed51071 100644 (file)
--- a/doc/rrdgraph_rpn.pod
+++ b/doc/rrdgraph_rpn.pod
@@ -346,7 +346,7 @@ B<STEPWIDTH>
 The with of the current step in seconds. You can use this to go back from
 rate based presentations to absolute numbers
 
-  CDEF:abs=rate,STEPWIDTH,*,PREF,ADDNAN
+  CDEF:abs=rate,STEPWIDTH,*,PREV,ADDNAN
 
 B<NEWDAY>,B<NEWWEEK>,B<NEWMONTH>,B<NEWYEAR>