my @stat = stat("$dir/$file")
   or die("Can't stat \"$dir/$file\": $!");

if ( -d _) {
   warn("\"$dir/$file\" is a dir\n");
   ...
}
elsif (-f _) {
   warn("\"$dir/$file\" is a file\n");
   ...
}
else {
   die(sprintf("\"%s\" is neither a file nor a dir (mode=%o)\n",
      "$dir/$file",
      $stat[2],
   ));
}