opendir(DIR, $some_dir) || die "can't opendir '$some_dir': $!";
while ($file = readdir(<DIR>)) {
   if ($file =~ /Somthing/){
         my  $fullpath = "$some_dir/$file";
         open(FILE, $fullpath) or die "can't open file '$fullpath' for reading: $!";
         while(<>) {
             if( m/PASS/ ) {
                 print $_;
             }
         }
         # look around ... I'm sure you can find examples
         # of reading files line by line
         close(FILE);
    }
close(DIR);