I use a free program called TextCrawler to find and replace text in multiple files at once. You can download it at TextCrawler - Seach and Replace Files
Notepad++ does this quite fine. It has a find and replace in files capability that you can utilize to update files with filters by file type and the ability to follow sub folders as well. Plus it's free.
notepad ++ find and replace in all opened documents. Load all 982 into notepad++ ctrl+f </head> > replace with <snip></head> press replace in all opened documents.