diff --git a/nnfc.awk b/nnfc.awk
index 67d9ad3..3962e05 100644
--- a/nnfc.awk
+++ b/nnfc.awk
@@ -1,4 +1,4 @@
-# no-nonsense FreeCell
+# no-nonsense FreeCell in POSIX AWK
 # run as: [n]awk -f nnfc.awk [-v ASCII=1] [-v MONOCHROME=1] [-v SEED=x]
 # commands: q - quit, u - undo,
 # [number] [number] - move from column/freecell to column/freecell/foundation: