There are some things that I have to perform a number of times and they require simple and quick solutions and searching and replacing text in a number of files normally constituting a project is one of them.
Sometimes there is the temptation to just code your own small application to do the task but this is unnecessary because there are a number of free utilities that do the job very well. For standalone applications I use very simple applications like TurboSR Search and Replace and Replace In files. Both are simple search and replace utilities that make changes to a whole range of text, HTML, XML or other text-based files including php.
The best scenario I think it to use an IDE that has an in-built function to replace text in a whole project if the files are source code files and one such example is PSPad . With PSPad you can specify whether you want to change and replace text in a project, open files or you can specify a folder as you would do with a stand-alone utility. I normally prefer project because I would be working in a project and at the end of the search I get a report specifying which files have been changed.