USAGE: grep.php?keyword=[search text pattern]&dir=[search from sub folder name, default: .]&extensions=[file extensions separated by commas character, default: php,js,css,html,phtml]
Ex:

1. grep.php?keyword=Pamysoft&extensions=php,js,css,html,phtml,tpl
2. grep.php?keyword=Pamysoft&dir=/subdir