FAR is a tool for searching and replacing multiple files. You can apply ordinary "word-by-word" replacement or choose to use full-featured regular expressions.
FAR automatically creates backups (unless you deselect this option) and is designed to work on files scattered across entire directory trees.
FAR was created out of the need to change the layout of a website with hundreds of html pages. While all editors know "find and replace" and most support regular expressions, only a few allow:
Modify a number of files in different directories at once.
Allow search (and replace) patterns that span multiple lines.