Replace Text in Many Files is described as 'tool you can use to search and modify text inside multiple files at once. The program includes full Unicode and different character encodings support'. There are more than 25 alternatives to Replace Text in Many Files for a variety of platforms, including Windows, Mac, Linux, BSD and PortableApps.com. The best alternative is grepWin, which is both free and Open Source. Other great apps like Replace Text in Many Files are grep (Free, Open Source), dnGREP (Free, Open Source), Search Monkey (Free, Open Source) and AstroGrep (Free, Open Source).
grepWin is a simple search and replace tool which can use PCRE regular expressions to search for strings of text within files. grepWin adds an entry to the shell context menu to easily search selected folders.
AstroGrep is A Microsoft Windows GUI File Searching (grep) utility. Features include regular expressions, versatile printing options, stores most recent used paths and has a "context" feature which is very nice for looking at source code.
regexxer is a nifty GUI search/replace tool featuring Perl-style regular expressions. If you need project-wide substitution and you’re tired of hacking sed command lines together, then you should definitely give it a try.
Quickly search through large numbers of files on your PC or network using powerful text patterns to find exactly the information you want. Search and replace with plain text or regular expressions to maintain web sites, source code, reports, ...