lib/Tools/getenv

--- a/lib/Tools/getenv	Sat Apr 02 23:29:05 2016 +0200
+++ b/lib/Tools/getenv	Sun Apr 03 19:47:29 2016 +0200
@@ -57,6 +57,7 @@
 
 # args
 
+[ -z "$ALL" -a -z "$DUMP" -a "$#" -eq 0 ] && usage
 [ -n "$ALL" -a "$#" -ne 0 ] && usage