return
    }
    if {$line eq {}} return
    set line [string trim $line]
    debug "([clientState $fd]:$fd) [clientNick $fd] -> '$line'"
    if {[clientState $fd] eq {UNREGISTERED}} {
	if {[regexp -nocase {NICK +([^ ]+)$} $line -> nick]} {
            if {[string index $nick 0] eq ":"} {
                set nick [string range $nick 1 end]
            stripColon nick
            }
	    if {[nickToFd $nick] ne {}} {
		rawMsg $fd "433 * $nick :Nickname is already in use."
		return
	    }
	    clientNick $fd $nick
	    nickToFd $nick $fd
	    if {[clientUser $fd] ne {}} {