#! perl

use IO::Socket;
use Storable qw/nfreeze thaw/;

my %global; # for use by eval'ed commands

sub tcp_serve($) {
   my ($fh) = @_;

   binmode $fh, ":raw:perlio:utf8";

   my $buf;
   my ($a,$b,$c,$d,%l,@l); # for use by shell users

   print $fh "Welcome\n> ";

   Event->io (fd => $fh, poll => 'r', cb => sub {
      if (defined (my $cmd = <$fh>)) {
         my $old_fh = select $fh;

         if ($cmd =~ /^\s*exit\b/i) {
            print "will not exit() server.\n";
         } else {
            {
               package cf;
               eval $cmd;
            }
            print $@ if $@;
         }

         print "> ";
         select $old_fh;
      } else {
         $_[0]->w->cancel;
      }
   });
}

# now a shell listening on a tcp-port - let the firewall decide access rights
if (my $listen = new IO::Socket::INET LocalAddr => "127.0.0.1:13322", Listen => 1, ReuseAddr => 1) {
   Event->io (fd => $listen, poll => 'r', cb => sub { tcp_serve $listen->accept });
}