my %commands = (
    'LS'   => \&lsftp,
    'DIR'  => \&dirftp,
    'GET'  => \&getftp,
    'PUT'  => \&putftp,
    'DEL'  => \&delftp,
    'SIZE' => \&sizeftp,
  );

  [...]

  my $cmd = $commands{$type};
  if(&$cmd($value1, $value2) == 1) {
    sleep $idletime;
    next;
  }