sub become_daemon {
  croak "Can't fork" unless defined (my $child = fork);
  exit 0 if $child;    # parent dies;
  POSIX::setsid();     # become session leader
  open(STDIN,"</dev/null");
  open(STDOUT,">/dev/null");
  open(STDERR,">&STDOUT");
  $CWD = getcwd;       # remember working directory
  chdir '/';           # change working directory
  umask(0);            # forget file mode creation mask
  $ENV{PATH} = '/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin';
  delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};
  $SIG{CHLD} = \&reap_child;
}