perl простой сервер, проблема с $client->close()

use IO::Socket::INET;
use threads;
use 5.010;

my $srv = IO::Socket::INET->new(LocalPort => 3000, Proto => 'tcp', Listen => 5,
                                Reuse => 1) or die $!;

while ($cli = $srv->accept()) {
    threads->create(
        sub {
            while ($cli) {
                $cli->recv($data, 1024);
                $data =~ s/\v//g;
                my ($cmd, $arg) = split ' ', $data;
                given ($cmd) {
                    when ('..')   { chdir ".." }
                    when ('ls')   { my $ls = join ' ', (glob "./*");
                                    $cli->send($ls . "\n");          }
                    when ('cd')   { chdir $arg or $cli->send("$!\n") }
                    when ('md')   { mkdir $arg or $cli->send("$!\n") }
                    when ('rmd')  { rmdir $arg or $cli->send("$!\n") }
                    when ('quit') { $cli->close }
                    when ('halt') { exit }
                    default       { $cli->send("Неизвестная команда\n")}
                };
       });
}

#-*- coding:utf-8 -*-
require 'socket'

server = TCPServer.new 3000
loop do
    Thread.start(server.accept) { |cli|
        while cli
            cmd, arg = cli.gets.chomp.split " "
            case cmd
                when ".."    then Dir.chdir ".." rescue cli.puts $!#"error"
                when "ls"    then cli.puts  Dir.glob("./*").join ' '
                when "cd"    then Dir.chdir arg  rescue cli.puts $!#"error"
                when "md"    then Dir.mkdir arg  rescue cli.puts $!#"error"
                when "rmd"   then Dir.rmdir arg  rescue cli.puts $!#"error"
                when "quit!" then cli.close
                when "halt!" then exit
                else         cli.puts "Неизвестная команда \n"
            end
        end
    }
end