This is an object oriented perl interface to the FreeBSD jail subsystem.

Here's a replica of the 'jls' utility in just a few lines of perl:

  use BSD::Jail::Object 'jids';

  print "   JID  IP Address      Hostname                      Path\n";
  printf "%6d  %-15.15s %-29.29s %.74s\n",
      $_->jid, $_->ip, $_->hostname, $_->path foreach jids( instantiate => 1 );

And here's 'jexec':

  my $j = BSD::Jail::Object->new( $ARGV[0] ) or die $@;
  $j->attach && chdir('/') && exec $ARGV[1] or exit;

For more info please use 'perldoc' on the module.