You could always make a PHP script to accomplish the same task. Have it [man]glob/man a directory of files (possibly specifying an extension, if you know it, e.g. "*.txt"), loop over the results and if it's a directory ([man]is_dir/man) then run the same function on that directory (e.g. a recursive search), else read the file in ([man]file_get_contents/man, for example) and search.