There is a myriad of unix scripts for doing such stuff out there, that is performing some s/$old/$new/ operations on filenames/folders/whatever you want, they are just not announced on websites as big applications because they're that easily written (and quicker than such webpages) and nothing to make big eyes about like some people in the Windows world might do.
As for GUI Apps there is
File Buddy performing some such operations, but I don't think it's worth the price.
Then OS X comes with a few
Finder Scripts that will do such tasks too and these AppleScripts can easily get extended.
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