diff --git a/pickups/__main__.py b/pickups/__main__.py
index a6a6b8d..5918f3c 100644
--- a/pickups/__main__.py
+++ b/pickups/__main__.py
@@ -12,14 +12,16 @@
     logging.basicConfig(level=logging.INFO, stream=sys.stdout)
     logging.getLogger('hangups').setLevel(logging.WARNING)
     dirs = appdirs.AppDirs('hangups', 'hangups')
-    default_cookies_path = os.path.join(dirs.user_cache_dir, 'cookies.json')
-    cookies = hangups.auth.get_auth_stdin(default_cookies_path)
 
     parser = argparse.ArgumentParser(description='IRC Gateway for Hangouts')
+    parser.add_argument('--cookies', help='cookies filename', default='cookies.json')
     parser.add_argument('--address', help='bind address', default='127.0.0.1')
     parser.add_argument('--port', help='bind port', default=6667)
     parser.add_argument('--ascii-smileys', action='store_true',
                         help='display smileys in ascii')
     args = parser.parse_args()
 
+    default_cookies_path = os.path.join(dirs.user_cache_dir, args.cookies)
+    cookies = hangups.auth.get_auth_stdin(default_cookies_path)
+
     Server(cookies, args.ascii_smileys).run(args.address, args.port)
diff --git a/pickups/irc.py b/pickups/irc.py
index 040a73d..cd7d216 100644
--- a/pickups/irc.py
+++ b/pickups/irc.py
@@ -1,4 +1,5 @@
 import logging
+from . import util
 
 RPL_WELCOME = 1
 RPL_WHOISUSER = 311
@@ -22,12 +23,14 @@
 
 class Client(object):
 
-    def __init__(self, reader, writer):
+    def __init__(self, server, reader, writer):
+        self.server = server
         self.reader = reader
         self.writer = writer
 
         self.nickname = None
         self.sent_messages = []
+        self.joined_channels = set()
 
     def readline(self):
         return self.reader.readline()
@@ -64,7 +67,12 @@ def list_channels(self, info):
 
     def join(self, channel):
         """Tells the client to join a channel."""
-        self.write(self.nickname, 'JOIN', ':{}'.format(channel))
+        self.joined_channels.add(channel)
+        self.write(self.nickname, 'JOIN', channel)
+        conv = util.channel_to_conversation(channel, self.server._conv_list)
+        self.topic(channel, util.get_topic(conv))
+        self.list_nicks(channel, (util.get_nick(user) for user in conv.users))
+
 
     def list_nicks(self, channel, nicks):
         """Tells the client what nicks are in channel."""
@@ -87,6 +95,8 @@ def topic(self, channel, topic):
 
     def privmsg(self, hostmask, target, message):
         """Sends the client a message from someone."""
+        if target not in self.joined_channels:
+            self.join(target)
         for line in message.splitlines():
             if line:
                 self.write(hostmask, 'PRIVMSG', target, ':{}'.format(line))
diff --git a/pickups/server.py b/pickups/server.py
index e5f5759..8269ad0 100644
--- a/pickups/server.py
+++ b/pickups/server.py
@@ -57,7 +57,7 @@ def _on_hangups_event(self, conv_event):
 
     def _on_client_connect(self, client_reader, client_writer):
         """Called when an IRC client connects."""
-        client = irc.Client(client_reader, client_writer)
+        client = irc.Client(self, client_reader, client_writer)
         task = asyncio.Task(self._handle_client(client))
         self.clients[task] = client
         logger.info("New Connection")
@@ -102,25 +102,37 @@ def _handle_client(self, client):
                 segments = hangups.ChatMessageSegment.from_str(message[1:])
                 asyncio.async(conv.send_message(segments))
             elif line.startswith('JOIN'):
-                channel = line.split(' ')[1]
-                conv = util.channel_to_conversation(channel, self._conv_list)
-                if not conv:
-                    client.swrite(irc.ERR_NOSUCHCHANNEL,
-                            ':{}: Channel not found'.format(channel))
-                else:
-                    # If a JOIN is successful, the user receives a JOIN message
-                    # as confirmation and is then sent the channel's topic
-                    # (using RPL_TOPIC) and the list of users who are on the
-                    # channel (using RPL_NAMREPLY), which MUST include the user
-                    # joining.
+                channel_line = line.split(' ')[1]
+                channels = channel_line.split(',')
+                for channel in channels:
+                    conv = util.channel_to_conversation(channel, self._conv_list)
+                    if not conv:
+                        client.swrite(irc.ERR_NOSUCHCHANNEL,
+                                ':{}: Channel not found'.format(channel))
+                    else:
+                        # If a JOIN is successful, the user receives a JOIN message
+                        # as confirmation and is then sent the channel's topic
+                        # (using RPL_TOPIC) and the list of users who are on the
+                        # channel (using RPL_NAMREPLY), which MUST include the user
+                        # joining.
+                        client.write(util.get_nick(self._user_list._self_user),
+                                     'JOIN', channel)
+                        client.topic(channel, util.get_topic(conv))
+                        client.list_nicks(channel, (util.get_nick(user)
+                                                    for user in conv.users))
+                        client.joined_channels.add(channel)
+            elif line.startswith('PART'):
+                channel_line = line.split(' ')[1]
+                channels = channel_line.split(',')
+                for channel in channels:
+                    if channel in client.joined_channels:
+                        client.joined_channels.remove(channel)
                     client.write(util.get_nick(self._user_list._self_user),
-                                 'JOIN', channel)
-                    client.topic(channel, util.get_topic(conv))
-                    client.list_nicks(channel, (util.get_nick(user)
-                                                for user in conv.users))
+                                 'PART', channel)
             elif line.startswith('WHO'):
                 query = line.split(' ')[1]
                 if query.startswith('#'):
+                    channel = line.split(' ')[1]
                     conv = util.channel_to_conversation(channel,
                                                          self._conv_list)
                     if not conv: