A more programmatic solution to finding the appropriate files can be found through using File::Find::Rule

use File::Find::Rule

my $rule = rule(
  file  =>
  name  => '*.out',
  grep  => qr/error/,
  start => \@directory_list,
);

while(my $file = $rule->match) {
  # send mail here
}
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See. the File::Find::Rule docs for more information on this most marvellous of modules.