Synopsis:
   nick [<new nickname>]

Description:
   The NICK command allows you to change your current nickname to something
   else.  If you choose a nickname that is already in use, you will receive
   an error message to that effect, and your nickname will not be changed.
   Nicknames are not case-sensitive.

   If you do not specify a new nickname, your current one is displayed.

Examples:
   To change your nick to foobar:
      /nick foobar

   To display your current nickname:
      /nick

See Also:
   on(5) channel_nick, nickname; set(4) auto_new_nick

Restrictions:
   Nicknames on IRC are restricted to 9 characters in total length (except
   on DALnet, where the limit is 30).  All nicknames must begin with a
   letter, and then may be followed by any letter, number or any of the
   following characters: - _ \ | [ ] { } ` ^

Other Notes:
   The special allowance for 30-character nicknames requires the client
   to be compiled with the #define "ALLOW_LONG_NICKNAMES" enabled.  This
   is done by default, but if for some reason the person compiling the
   client has disabled it, any attempts to use a nickname longer than 9
   characters will be truncated to 9 characters.  This can be circumvented
   by using the raw server NICK command: /quote nick <new nick>