Synopsis:
   topic <channel> [<new topic>]
   topic [<new topic>]
   
Description:
   With this command you can change the current topic of the specified
   channel.  If no new topic is specified, the current one is displayed.
   If the new topic is not specified AND either the channel name is prefixed
   with a hyphen (a "-") or the hyphen is the only argument, the topic
   for the assumed channel will be removed.

Examples:
   To set a new topic on your channel:
      /topic #blah Welcome to #blah, a very serious channel.
      or
      /topic Welcome to #blah, a very serious channel.

   To view the current topic for your channel:
      /topic #blah
      or
      /topic
      
   To unset the topic for your channel:
      /topic -#blah
      or
      /topic -

See Also:
   mode(1); on(5) topic

Restrictions:
   On channels with channel mode +t set, only channel operators may
   change the topic (though anyone may view it).

Other Notes:
   Most modern IRC servers support the 333 numeric.  When using TOPIC to
   display the current topic, it will also display the person who placed
   it.  This feature originated on the Undernet.