Index: trunk/Ohana/src/opihi/cmd.data/accum.c
===================================================================
--- trunk/Ohana/src/opihi/cmd.data/accum.c	(revision 3897)
+++ trunk/Ohana/src/opihi/cmd.data/accum.c	(revision 3898)
@@ -16,4 +16,5 @@
   if ((argc != 6) && (argc != 7)) {
     fprintf (stderr, "USAGE: accum <value> <vector> <key> start end [delta]\n");
+    fprintf (stderr, "  sum <value> in bins corresponding to the value of <key>\n");
     return (FALSE);
   }