Search and Replace (ok, it's not an original name...) replaces characters in recursive directories and files line by line, with a strong suite of options for prompted replaces. It's a medium size utility written in Perl. It's very useful for replacing things like domain names, etc. On one client's system it processed 13,029 files, with 7,487 replaces, in 11 seconds. It also writes its operation output to a log file, so you can check what it did.
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