Index: trunk/ippScripts/scripts/detrend_reject.pl
===================================================================
--- trunk/ippScripts/scripts/detrend_reject.pl	(revision 8194)
+++ trunk/ippScripts/scripts/detrend_reject.pl	(revision 8197)
@@ -10,4 +10,9 @@
 use constant RECIPE => "PPSTATS_REJECT"; # Recipe to use on residuals
 use constant CLIP => 3;		# Rejection limit for sigma clipping
+
+if (scalar @ARGV == 0) {
+    die "Output rejected images from a stack, based on their statistics.\n\n" .
+	"Usage: $0 FILE_1.fits FILE_2.fits FILE_3.fits ...\n\n";
+}
 
 # look for commands we need