--- a/pvl/syslog/filter.py	Fri Jan 04 22:38:44 2013 +0200
+++ b/pvl/syslog/filter.py	Fri Jan 04 23:47:31 2013 +0200
@@ -25,6 +25,10 @@
             # ignore
             return None
 
+        if not prog :
+            # require
+            return False
+
         # normalize
         prog = prog.strip().lower()
         _, prog = os.path.split(prog)