diff --git a/bin/bak b/bin/bak
new file mode 100755
index 0000000..4efb3ff
--- /dev/null
+++ b/bin/bak
@@ -0,0 +1,14 @@
+#!/bin/sh
+
+bakrotate() {
+  if [ -f $1 ]
+  then
+    if [ -f "$1.bak" ]
+    then bakrotate "$1.bak"
+    fi
+    mv "$1" "$1.bak"
+  fi
+}
+
+bakrotate "$1.bak"
+cp $1 $1.bak