Synopsis:
   join [-invite|<channel list> [<key>]]

Description:
   JOIN lets you join a new channel.  If you are on multiple channels,
   the specified channel will become the current one.  If you do not
   specify a channel (or channels) to join, your client will display
   your current channels, along with their respective modes and users,
   and which server you are on the channel from.

   You may join more than channel at a time with a single JOIN command
   by separating the channels with commas.  If a key (channel mode +k)
   is set on a channel you wish to join, you must specify that key in
   the JOIN command to be able to join the channel.

   You can create a new channel simply by joining a channel that does
   not exist.  Channel names begin with a '#', a '&' (&channels are local
   to your server), or a '+' (modeless channels, not available everywhere)
   and following that may consist of any character except SPACE, BELL, NUL,
   CR, LF, or comma (',').  Channel names may be up to 200 characters in
   length.  Additionally, a channel may be restricted to only users from
   certain hosts, by adding a hostmask to the end of the channel name,
   separated with a ':' (this is not supported everywhere).

Options:
   -invite   makes you join the last channel to which you were INVITEd

Examples:
   To join channel #blah (or create it if it does not exist):
      /join #blah

   To join channel #blah that has the key "foobar":
      /join #blah foobar

   To join more than one channel at once:
      /join #foo,#bar,&blah

   To join a channel that only German users may join:
      /join #blah:*.de

   To join channel #blah if you have been invited to it (either will
   work, although the first is better, since channel names may contain
   characters that your terminal can't display):
      /join -invite
      /join #blah

Aliases:
   CHANNEL is identical in operation to JOIN.

See Also:
   bind(4) switch_channels; invite(1); mode(1); on(5) join; set(4) novice;
   window(4) channel

Restrictions:
   The ability to join a channel can be restricted by the channel's modes.
   If mode +k is set, you must specify the channel's key to join.  If mode
   +i is set, you must first be INVITEd.  If mode +l is set, and the limit
   has been reached, you cannot join.  If a ban (mode +b) has been set
   that matches your nick!user@host pattern, you cannot join.  See MODE
   for more information.

Other Notes:
   The ircII client provides a NOVICE mode mechanism.  When turned on, the
   client will not allow you to join more than one channel at once.  If
   you are on a channel and try to join another, it will first make you
   leave the first channel.