diff --git a/share/examples/slattach/unit-command.sh b/share/examples/slattach/unit-command.sh
new file mode 100755
index 00000000000..9e97ffdcd69
--- /dev/null
+++ b/share/examples/slattach/unit-command.sh
@@ -0,0 +1,18 @@
+#!/bin/sh
+
+old_unit=$1
+new_unit=$2
+
+if [ $old_unit != -1 ]; then
+	ifconfig sl$old_unit delete down
+	if [ $new_unit == -1 ]; then
+		route delete default
+	fi
+fi
+
+if [ $new_unit != -1 ]; then
+	ifconfig sl$new_unit <address1> <address2>
+	if [ $old_unit == -1 ]; then
+		route add default <address2>
+	fi
+fi