If you're already going to write a Perl script, why shelling out? Do it all in Perl - or does speed matter that much?

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

my @start_dirs = qw(/home/bob/mytemp);

sub rm_empty_file {
  my $file = $File::Find::name;

  if ( -f $file and -z $file ) {
    print "removing empty file: $file\n";
    #TODO: unlink $file or die "cannot remove $file - $!";
  }
}

find( { wanted => \&rm_empty_file, no_chdir => 1 }, @start_dirs );
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