Index: /trunk/psphot/src/psphot.c
===================================================================
--- /trunk/psphot/src/psphot.c	(revision 7729)
+++ /trunk/psphot/src/psphot.c	(revision 7730)
@@ -1,3 +1,8 @@
 # include "psphot.h"
+
+static void usage (void) {
+    fprintf (stderr, "USAGE: ppImage [-file INPUT.fits] [-list INPUT.txt] OUTPUT\n");
+    exit (2);
+}
 
 int main (int argc, char **argv) {
@@ -15,8 +20,5 @@
     // load command-line arguments, options, and system config data
     pmConfig *config = psphotArguments (argc, argv);
-    if (config == NULL) {
-        psErrorStackPrint(stderr, "");
-        exit(1);
-    }
+    if (config == NULL) usage ();
 
     // load input data (config and images (signal, noise, mask)