diff --git a/lora.py b/lora.py
index a356077..c4f1baf 100644
--- a/lora.py
+++ b/lora.py
@@ -27,6 +27,7 @@ import contextlib
 import functools
 import itertools
 import os
+import sys
 import unittest
 
 from Strobe.Strobe import Strobe, KeccakF
@@ -203,6 +204,105 @@ class MulticastSyncDatagram(SyncDatagram):
 		self.mt.close()
 		self.mt = None
 
+def listsplit(lst, item):
+	try:
+		idx = lst.index(item)
+	except ValueError:
+		return lst, []
+
+	return lst[:idx], lst[idx + 1:]
+
+async def main():
+	import argparse
+
+	from loraserv import DEFAULT_MADDR as maddr
+
+	parser = argparse.ArgumentParser()
+
+	parser.add_argument('-r', dest='client', metavar='module:function', type=str,
+	    help='Create a respondant instead of sending commands.  Commands will be passed to the function.')
+	parser.add_argument('-s', dest='shared_key', metavar='shared_key', type=str, required=True,
+	    help='The shared key (encoded as UTF-8) to use.')
+	parser.add_argument('args', metavar='CMD_ARG', type=str, nargs='*',
+	    help='Various commands to send to the device.')
+
+	args = parser.parse_args()
+
+	shared_key = args.shared_key.encode('utf-8')
+
+	if args.client:
+		# Run a client
+		mr = await multicast.create_multicast_receiver(maddr)
+		mt = await multicast.create_multicast_transmitter(maddr)
+
+		from ctypes import c_uint8
+
+		# seed the RNG
+		prngseed = os.urandom(64)
+		lora_comms.strobe_seed_prng((c_uint8 *
+		    len(prngseed))(*prngseed), len(prngseed))
+
+		# Create the state for testing
+		commstate = lora_comms.CommsState()
+
+		import util_load
+		client_func = util_load.load_application(args.client)
+
+		def client_call(msg, outbuf):
+			ret = client_func(msg._from())
+
+			if len(ret) > outbuf[0].pktlen:
+				ret = b'error, too long buffer: %d' % len(ret)
+
+			outbuf[0].pktlen = min(len(ret), outbuf[0].pktlen)
+			for i in range(outbuf[0].pktlen):
+				outbuf[0].pkt[i] = ret[i]
+
+		cb = lora_comms.process_msgfunc_t(client_call)
+
+		# Initialize everything
+		lora_comms.comms_init(commstate, cb, make_pktbuf(shared_key))
+
+		try:
+			while True:
+				pkt = await mr.recv()
+				msg = pkt[0]
+
+				out = lora_comms.comms_process_wrap(
+				    commstate, msg)
+
+				if out:
+					await mt.send(out)
+		finally:
+			mr.close()
+			mt.close()
+		sys.exit(0)
+
+	msd = MulticastSyncDatagram(maddr)
+	await msd.start()
+
+	l = LORANode(msd, shared=shared_key)
+
+	await l.start()
+
+	valid_cmds = { 'waitfor', 'runfor', 'ping', 'terminate', }
+
+	cmdargs = list(args.args)
+	while cmdargs:
+		cmd = cmdargs.pop(0)
+
+		if cmd not in valid_cmds:
+			print('invalid command:', repr(cmd))
+			sys.exit(1)
+
+		fun = getattr(l, cmd)
+		args, cmdargs = listsplit(cmdargs, '--')
+
+		await fun(*(int(x) for x in args))
+
+if __name__ == '__main__':
+	asyncio.run(main())
+
 class MockSyncDatagram(SyncDatagram):
 	'''A testing version of SyncDatagram.  Define a method runner which
 	implements part of the sequence.  In the function, await on either
diff --git a/util_load.py b/util_load.py
new file mode 100644
index 0000000..c96a78f
--- /dev/null
+++ b/util_load.py
@@ -0,0 +1,72 @@
+# Copyright P G Jones 2018.
+#
+# Permission is hereby granted, free of charge, to any person
+# obtaining a copy of this software and associated documentation
+# files (the "Software"), to deal in the Software without
+# restriction, including without limitation the rights to use,
+# copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following
+# conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+# OTHER DEALINGS IN THE SOFTWARE.
+#
+
+# Obtained from:
+# https://github.com/pgjones/hypercorn/blob/master/src/hypercorn/utils.py
+#
+# Slightly modified to adapt to my uses.
+#
+# Remove import path from sys.path as part of clean up.
+#
+# Use getattr instead of eval.
+
+import sys
+
+from pathlib import Path
+from importlib import import_module
+
+def load_application(path: str):
+	try:
+		module_name, app_name = path.split(":", 1)
+	except ValueError:
+		module_name, app_name = path, "app"
+	except AttributeError:
+		raise ValueError()
+
+	module_path = Path(module_name).resolve()
+	added_module = str(module_path.parent)
+	sys.path.insert(0, added_module)
+	try:
+		if module_path.is_file():
+			import_name = module_path.with_suffix("").name
+		else:
+			import_name = module_path.name
+		try:
+			module = import_module(import_name)
+		except ModuleNotFoundError as error:
+			if error.name == import_name:
+				raise ValueError('module %s not found' %
+				    repr(import_name))
+			else:
+				raise
+
+		try:
+			for i in app_name.split('.'):
+				module = getattr(module, i)
+			return module
+		except AttributeError:
+			raise ValueError('attribute %s not found on %s' %
+			    (repr(i), repr(module)))
+	finally:
+		sys.path.remove(added_module)