use strict;
use warnings;
use File::Find;

sub wanted {
  my $file = $File::Find::name;
  print "$File::Find::name is a ", -d $file ? 'directory' : 'file', $/;
}

sub filter {
  grep {
    my $file = "$File::Find::dir/$_";
    if (-d $file) {
      my $depth = $file =~ s#/#/#g;
      if ($depth > 3) {
        print "Depth > 3 in $file ... skipping\n";
        0;  # return as grep result for this $file
      } else {
        1;  # concider this to recurse into
      }
    } else {
      1;   # include non-dirs
    }
  } grep !/^\.\.?$/, @_;
}

find(
  {
    no_chdir => 1,
    wanted => \&wanted,
    preprocess => \&filter,
  },
  shift

);