#!/usr/bin/perl 

use strict;

use IO::Socket;

use IO::Select;

use Getopt::Std; 

my %option;getopts('lp:', %option);

# listen on local port

if( defined $option{'l'} )

{

    if( !defined $option{'p'} )

    {

        &Usage( );

        exit( - );

    }

    my $port = $option{'p'};

    my $listen = IO::Socket::INET->new(Proto => 'tcp',

    LocalPort => $port,

    Listen => ,

    Reuse => ) or die "Listen on port $port error: $!n";

    while( my $client_sock = $listen->accept() )

    {

        &ProcessData( $client_sock );

    }

} 

# if has no -l argument, maybe want to connect to other host

if( @ARGV !=  )

{

    &Usage( );

    exit( - );

}

my $client_sock = IO::Socket::INET->new(Proto => 'tcp',

 PeerHost => $ARGV[],

 PeerPort => $ARGV[] ) || die "Connect to $ARGV[0]:$ARGV[1] error:$!n";

 &ProcessData( $client_sock );

 sub ProcessData

 {

    my $client_sock = shift;

    my $select = IO::Select->new( );

    $select->add( *STDIN );

    $select->add( $client_sock );

    my $buffer;

    while(  )

    {

        if( ! $select->exists( $client_sock ) )

        {

            print "waiting connection....n";

            last;

        }

        my @ready = $select->can_read;

        for my $tmp_sock(@ready)

        {

            if( $tmp_sock eq *STDIN )

            {

                if( my $recv_len = sysread( *STDIN, $buffer,  )  )

                {

                    if( ! syswrite($client_sock, $buffer) )

                    {

                        $select->remove( $client_sock );

                        $select->remove( *STDIN );

                        close( $client_sock );

                        last;

                    }

                }

                else

                {

                    $select->remove( $client_sock );

                    $select->remove( *STDIN );

                    close( $client_sock );

                    last;

                }

            }

            elsif( $tmp_sock eq $client_sock )

            {

                if( my $recv_len = sysread( $client_sock, $buffer, * ) )

                {

                    if( ! syswrite( *STDOUT, $buffer) )

                    {

                        $select->remove( $client_sock );

                        $select->remove( *STDIN );

                        close( $client_sock );

                        last;

                    }

                }

                else

                {

                    print "socket disconnected.n";

                    $select->remove( $client_sock );

                    $select->remove( *STDIN );

                    close( $client_sock );

                    last;

                }

            }

        }

    }

}

 sub Usage

 {

    print "simple nc.pl, code by wustyunshu@hotmail.comn";

    print "this script don't support -e cmd.exe, ^_^n";

    print "Usage:n";

    print "t  -l -p 99n";

    print "t 192.168.0.1 80n";

}