Add "serve.sh", a script to serve another script's output via netcat

bsp/default/root_file_system/etc/serve.sh

@@ -0,0 +1,13 @@
+#!/bin/ash
+
+[ $# -ge 3 ] || exit 1
+
+PORT="$1"
+DELAY="$2"
+shift 2
+COMMAND="$@"
+
+while true; do
+	(nc -l -p $PORT -e $COMMAND) > /dev/null 2>&1
+	sleep $DELAY
+done