diff --git a/good.sh b/good.sh
new file mode 100644
index 0000000..5e2ebc1
--- /dev/null
+++ b/good.sh
@@ -0,0 +1,13 @@
+#! /bin/bash
+
+set -eu
+
+IFS=$'\n\t'
+
+test $# -eq 1 || exit 1
+
+[ -d ${1:-} -o -f ${1:-} ] || exit 2 
+
+[[ $1 =~ \.\. ]]  &&  exit 3
+
+echo rm -f $1