#!/usr/bin/perl -w
use IO::Socket::UNIX;
use strict;
my $sockfile = '/tmp/mysocket';
my $r;
unlink($sockfile);
my $usock = new IO::Socket::UNIX(
   Type => SOCK_STREAM, 
   Local => $sockfile, 
   Listen => 1) 
  || die "ERROR: $!\n"; 

while (1) {
  if (($r) = $usock->accept) {
    my $out = do_something($r);
    $r->printflush($out);
    # sleep 1; # this makes it work
    $r->close;
  }
}

sub do_something {
  my ($fh) = @_; 
  my ($l) = <$fh>;
  return uc($l);
}

##</code><code>##

#!/usr/bin/perl -w
use IO::Socket::UNIX;
my ($sockfile) = shift 
  || die "$0: Socket address required\n";
my $r;
my $usock = new IO::Socket::UNIX (Type  => SOCK_STREAM,
				  Peer => $sockfile)
    || die "ERROR: $!\n";

# read stdin and write to socket
while(<>) {
    print $usock $_;
}

# shut down writing side (server receives EOF)
$usock->shutdown(1);
$sock->blocking(1);  # this does not help

# read socket (blocking) and write to stdout
while(<$usock>) {
    print $_;
}

# shut down reading side
$usock->shutdown(0);

##</code><code>##

my $linger = pack('ii', 1, 120); # BSD struct 
$usock->sockopt(SO_LINGER, $linger);