Red Hat

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#!/usr/bin/perl

 # server1.pl - a simple server


 use strict;

 use Socket;


 # use port 7890 as default

 my $port = shift || 7890;

 my $proto = getprotobyname('tcp');


 # create a socket, make it reusable

 socket(SERVER, PF_INET, SOCK_STREAM, $proto) or die "socket: $!";

 setsockopt(SERVER, SOL_SOCKET, SO_REUSEADDR, 1) or die "setsock: $!";


 # grab a port on this machine

 my $paddr = sockaddr_in($port, INADDR_ANY);


 # bind to a port, then listen

 bind(SERVER, $paddr)      or die "bind: $!";

 listen(SERVER, SOMAXCONN) or die "listen: $!";

 print "SERVER started on port $port\n";

 $| = 1;


 # for each connection...

 my $client_addr;

 while ($client_addr = accept(CLIENT, SERVER)) {
    # find out who connected
    my ($client_port, $client_ip) =
                     sockaddr_in($client_addr);
    my $client_ipnum = inet_ntoa($client_ip);
    my $client_host =
             gethostbyaddr($client_ip, AF_INET);
    # tell who connected
    print "got a connection from: $client_host",
          " [$client_ipnum]\n";
    # send them a message, close connection
    my $w = `w`;
    # log the access event
    print CLIENT "$w\n ";
    close CLIENT;

 }