Index: trunk/Ohana/src/tools/src/fields.c
===================================================================
--- trunk/Ohana/src/tools/src/fields.c	(revision 40408)
+++ trunk/Ohana/src/tools/src/fields.c	(revision 40409)
@@ -96,4 +96,5 @@
 	  }
 	}
+	// we are checking each extension to see if it matches the regex.
 	if (!regexec (&preg, extname, 0, NULL, 0)) {
 	  GotField &= print_fields (filename, extname, &header, argc, argv);
@@ -105,4 +106,8 @@
 	Nextend ++;
 
+	// this implementation is very inefficient!
+	// since we are checking each header for a regex, we should
+	// loop over all extensions once.  the function below reads the
+	// entire file a second time
 	GotFile &= gfits_read_Xheader (filename, &header, Nextend);
 	continue;