added an environment variable example

scripts/env_example.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# This example demonstrates that if the BASH_ENV_EX environment variable is set then it will print it out
+# If not it assigns a default as an empty string which will evaluate to false.
+
+set -e
+
+if [ -n "${BASH_ENV_EX:-}" ]; then
+    echo $BASH_ENV_EX
+else
+    echo "You didn't set the BASH_ENV_EX"
+fi