checkDir('/usr/tmp', sub { -w shift }); # need write permission.
checkDir('/usr/tmp', sub { -r shift }); # need read permission.
checkDir('/usr/tmp', sub { my $x = shift; -r $x and -w $x; }); # need both.
checkDir('/usr/tmp', sub { my $x = shift; not $x =~ /\.\./; }); # safety check.

sub checkDir {
  my ($path, $perm) = @_;
  ### Check if output dir exists
  if (! defined $path) {
    LOG ("Output path not defined; using temp instead...", 1);
    $path = '/var/tmp/';
   }
  if (! -d $path) {
    die LOG ("$path is not a valid directory...", 0);
  }
  if (! $perm->($path)) {
    die LOG ("Test failed on $path, not able to use it.", 0);
  }
  LOG ("Using $path as output directory...", 2);
}