Index: /trunk/ippTools/src/dettool.c
===================================================================
--- /trunk/ippTools/src/dettool.c	(revision 8503)
+++ /trunk/ippTools/src/dettool.c	(revision 8504)
@@ -3689,4 +3689,25 @@
     PS_ASSERT_PTR_NON_NULL(config, false);
 
+    // either -rerun or -stop must be specified
+    bool status = false;
+    bool again = psMetadataLookupBool(&status, config->args, "-again");
+    if (!status) {
+        psError(PS_ERR_UNKNOWN, false, "failed to lookup value for -again");
+        return false;
+    }
+    bool stop = psMetadataLookupBool(&status, config->args, "-stop");
+    if (!status) {
+        psError(PS_ERR_UNKNOWN, false, "failed to lookup value for -stop");
+        return false;
+    }
+    if (!(again || stop)) {
+        psError(PS_ERR_UNKNOWN, true, "either -again or -stop must be specified");
+        return false;
+    }
+    if (again && stop) {
+        psError(PS_ERR_UNKNOWN, true, "either -again or -stop must be specified");
+        return false;
+    }
+
     return true;
 }
Index: /trunk/ippTools/src/dettoolConfig.c
===================================================================
--- /trunk/ippTools/src/dettoolConfig.c	(revision 8503)
+++ /trunk/ippTools/src/dettoolConfig.c	(revision 8504)
@@ -401,5 +401,5 @@
     psMetadataAddStr(updatedetrunArgs, PS_LIST_TAIL, "-det_id",  0,
         "search for detrend master for detrend ID (required)", NULL);
-    psMetadataAddBool(updatedetrunArgs, PS_LIST_TAIL, "-rerun",  0,
+    psMetadataAddBool(updatedetrunArgs, PS_LIST_TAIL, "-again",  0,
         "start a new iteration of this detrend run", false);
     psMetadataAddBool(updatedetrunArgs, PS_LIST_TAIL, "-stop",  0,