[<channel>] [--{exact,nick,user,host}] <nick> [<seconds>] [<reason>]
If you have the #channel,op capability, this will kickban <nick> for
as many seconds as you specify, or else (if you specify 0 seconds or
don't specify a number of seconds) it will ban the person indefinitely.
--exact bans only the exact hostmask; --nick bans just the nick;
--user bans just the user, and --host bans just the host. You can
combine these options as you choose. <reason> is a reason to give for
the kick.
<channel> is only necessary if the message isn't sent in the channel
itself.