#!/usr/bin/perl
$|++;
use IO::Socket;
use IO::Select;
my $lsn = IO::Socket::INET->new( 
    Listen    => 10,
    LocalAddr => 'localhost',
    LocalPort => 9000
);
my $client = new IO::Select( $lsn );
while( my @ready = $client->can_read ) {
    for my $fh (@ready) {
        if($fh == $lsn) {
            warn "Accepted new socket\n";
            my $new = $lsn->accept;
            $client->add($new);
        }
        else {
            # process socket
            sysread($fh, $_, 1 );
            print;   # NB syswrite(STDOUT,$_,1) will be unbuffered by default
        }
    }
}