If you're not a PHP programmer the following info is a complete waste of time. You've been warned.
To tell the truth I've almost finished writing another "Why I dislike PEAR?" article, but under a fit of creativity I've completely forgot what I want to tell in the first place. So I stripped all spicy stuff and left only fruits.
Let me introduce my tool http://pear.php.net/package/File_SearchReplace/ written by Richard Heyes (http://www.phpguru.org/ ). Very useful PHP library for filtering files, bunch of .html or sources all at once. It is a low-level analog of numerous "Search and Replace" utilities. Well written articles about how to use it are here:
The main flaw in this library that it doesn't support Search without Replace. By calling doSearch() you immediately start write modifications. No preview, no read-only grep. This may become quite dangerous and was meant to be changed in version 2 or even in another new package that was proposed , but the proposal has been rejected. That's why I disliked PEAR. There is no way to change API even though this API is a bug in the first place. It was also not possible to release new refactored version with new API without the approval. You have to be nice and polite and even then nobody guarantees that your arguments are acceptable. The method for search without replace could be easily added if not this PEAR bureaucracy and backwards compatibility talks.
Since a lot of time has passed and I still can't release a package, it will be good to say something about planned modifications and let people use proper API to avoid possible conflicts in the future. I am not able to support PEAR packages anymore, because I've switched to SVN and Python (sorry), moreover and I do not know any convenient CVS tools that work through the proxy, but just in case somebody will get the courage to take over development my last advice to those who still use this library.
If you intend to use this package in future - use doReplace() method instead of doSearch(). doReplace() method is not documented, because 1.0.1 doesn't have it, but it more accurately describes what SearchReplace() do. It may happen that in futer doSearch() will be used just for search and statistics collection. Now that you've been warned you may edit your scripts with the goal for better future compatibility in mind (sorry, couldn't resist to include usual marketing crap).