--- zforce.in	2007-02-05 21:54:26.000000000 +0100
+++ zforce.in.oden	2008-12-19 16:39:43.000000000 +0100
@@ -58,7 +58,7 @@
     continue
   fi
 
-  if gzip -lv < "$i" 2>/dev/null | grep '^defl' > /dev/null; then
+  if gzip -l < "$i" 2>/dev/null | grep '^compressed' > /dev/null; then
 
     new="$i.gz"
     if mv "$i" "$new"; then